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\end_header |
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|
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\begin_body |
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|
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\begin_layout Chapter |
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Vessel Model for Beginners |
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\begin_inset CommandInset label |
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LatexCommand label |
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name "cha:model1" |
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|
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\end_inset |
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|
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|
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\end_layout |
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|
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\begin_layout Standard |
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You read our propaganda about the ASCEND system in which we said it was |
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to help technical people create hard models. |
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We said you can tackle really large models -- 100,000 equations, compiling |
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and solving them in minutes on a PC. |
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We also pointed out that you can readily solve the small problems many |
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currently solve using a spreadsheet, only once posed you can solve them |
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inside out, upside down and backwards. |
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|
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\end_layout |
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|
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\begin_layout Standard |
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This sounded intriguing so you downloaded the system and installed it. |
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Hopefully, this proved quite straight forward. |
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You double-clicked the ASCEND icon on your desktop and started it up for |
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the first time. |
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Four windows opened up. |
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You panicked. |
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|
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\end_layout |
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|
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\begin_layout Standard |
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Who wouldn't? |
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\end_layout |
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|
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\begin_layout Standard |
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To use this system properly requires that you learn how to use it. |
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If you pay the price to do so - and we hope it is not a large price, then |
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we believe you will find the tools we have provided to help you create |
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and debug models will pay you back handsomely. |
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|
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\end_layout |
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|
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\begin_layout Standard |
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This chapter |
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\noun off |
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and the next two chapters ( |
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\noun default |
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Chapter |
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\noun off |
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|
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\begin_inset CommandInset ref |
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LatexCommand ref |
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reference "cha:model2" |
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|
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\end_inset |
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|
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and |
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\noun default |
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Chapter |
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\begin_inset CommandInset ref |
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LatexCommand ref |
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reference "cha:model3" |
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|
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\end_inset |
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) |
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\noun default |
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are meant to be a good first step along the path to learning how to use |
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ASCEND. |
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We |
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\noun default |
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will |
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\noun off |
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lead you through the steps for creating and testing a simple model. |
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You will also learn how to improve this model so it may be more readily |
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shared with others. |
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We will present our reasons for the steps we take. |
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We |
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\noun default |
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will |
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\noun off |
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show you all the buttons you should push as you proceed. |
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\end_layout |
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|
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\begin_layout Standard |
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We strongly suggest you put time aside and go through all three of these |
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early chapters to introduce yourself to ASCEND. |
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It should take you about two to three hours. |
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The second chapter is particularly important if you wish to understand |
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our approach to good modeling practices. |
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\end_layout |
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the problem |
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\end_layout |
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|
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\end_inset |
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|
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Step 1: |
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\emph on |
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We are going to create and test an ASCEND model to compute, the mass of |
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the metal in the sides and ends of the thin-walled cylindrical vessel |
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\emph default |
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|
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\begin_inset Index idx |
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status collapsed |
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\begin_layout Plain Layout |
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vessel |
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\end_layout |
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|
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\end_inset |
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|
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|
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\emph on |
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shown in Figure |
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\begin_inset CommandInset ref |
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LatexCommand ref |
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reference "fig:model1.thinWalledVessel" |
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|
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\end_inset |
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. |
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|
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\end_layout |
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\begin_inset space ~ |
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|
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\begin_inset Graphics |
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filename howto-model1Fig1.eps |
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BoundingBox 0bp 0bp 280bp 260bp |
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|
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\end_inset |
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|
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|
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\end_layout |
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|
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\begin_layout Plain Layout |
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\begin_inset Caption Standard |
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|
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\begin_layout Plain Layout |
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A thin-walled cylindrical vessel with flat ends |
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\begin_inset CommandInset label |
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LatexCommand label |
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name "fig:model1.thinWalledVessel" |
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|
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\end_inset |
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\end_layout |
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\end_layout |
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\end_inset |
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|
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\end_layout |
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|
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\begin_layout Standard |
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Step 2: |
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\emph on |
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This model is to become a part of a library of models which others can use |
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in the future. |
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You must document it. |
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You must add methods to it to make it easy for others to make it well-posed. |
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You should probably parameterize it, and finally you must create a script |
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which anyone can easily run that solves an example problem to illustrate |
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its use. |
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\end_layout |
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|
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\begin_layout Standard |
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\begin_inset Marginal |
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status collapsed |
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topics covered |
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\end_layout |
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|
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\end_inset |
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|
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Topics covered in this and the following two chapters are: |
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\end_layout |
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|
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\begin_layout Itemize |
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\begin_inset Marginal |
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status collapsed |
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\begin_layout Plain Layout |
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T |
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\noun off |
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his chapter) |
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\end_layout |
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|
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\end_inset |
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|
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Converting the word description to an ASCEND model. |
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\end_layout |
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|
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\begin_layout Itemize |
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Loading the model into ASCEND, dealing with the error messages. |
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\end_layout |
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|
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\begin_layout Itemize |
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Compiling the model. |
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\end_layout |
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|
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\begin_layout Itemize |
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Browsing the model to see if it looks right |
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\end_layout |
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|
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\begin_layout Itemize |
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Solving the model. |
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\end_layout |
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|
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\begin_layout Itemize |
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Examining the results. |
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\end_layout |
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|
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\begin_layout Itemize |
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More thoroughly testing the model. |
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\end_layout |
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|
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\begin_layout Itemize |
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\begin_inset Marginal |
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status collapsed |
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|
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\begin_layout Plain Layout |
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Chapter |
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\begin_inset space ~ |
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\end_inset |
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|
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|
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\begin_inset CommandInset ref |
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LatexCommand vref |
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reference "cha:model2" |
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|
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\end_inset |
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|
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|
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\end_layout |
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|
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\end_inset |
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|
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Converting the model to a more reusable form by adding methods to it and |
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by parameterizing it. |
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\end_layout |
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|
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\begin_layout Itemize |
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Creating a script to load and execute an instance of the model. |
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\end_layout |
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|
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\begin_layout Itemize |
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\begin_inset Marginal |
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status collapsed |
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|
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\begin_layout Plain Layout |
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Chapter |
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\begin_inset space ~ |
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\end_inset |
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|
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|
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\begin_inset CommandInset ref |
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LatexCommand vref |
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reference "cha:model3" |
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|
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\end_inset |
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|
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|
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\end_layout |
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|
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\end_inset |
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|
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Creating an array of models. |
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\end_layout |
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|
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\begin_layout Itemize |
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Using an existing library model for plotting. |
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\end_layout |
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|
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\begin_layout Itemize |
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Creating a case study using the model. |
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\end_layout |
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|
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\begin_layout Standard |
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We shall introduce many of the features of the modeling language as well |
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as the use of the interactive interface you use when compiling, debugging, |
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solving and exploring your model. |
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Language features include units conversion, arrays and sets. |
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\end_layout |
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|
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\begin_layout Section |
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Converting the word description into an ASCEND model |
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\begin_inset CommandInset label |
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LatexCommand label |
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name "sec:model1.converting-the-word" |
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|
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\end_inset |
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|
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|
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\end_layout |
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|
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\begin_layout Standard |
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\begin_inset Marginal |
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status collapsed |
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|
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\begin_layout Plain Layout |
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an ASCEND model is a type |
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\begin_inset Index idx |
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status collapsed |
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|
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\begin_layout Plain Layout |
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type |
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\end_layout |
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|
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\end_inset |
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|
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definition |
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\end_layout |
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|
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\end_inset |
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|
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Every ASCEND model is, in fact, a type definition. |
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To "solve a model," we make an instance |
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\begin_inset Index idx |
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status collapsed |
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|
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\begin_layout Plain Layout |
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instance |
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\end_layout |
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|
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\end_inset |
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|
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of a type and solve the instance. |
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So we shall start by creating a vessel type definition. |
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We will have to create our type definition as a text file using a text |
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editor. |
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(Some simple text editors |
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\begin_inset Index idx |
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status collapsed |
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|
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\begin_layout Plain Layout |
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text editors |
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\end_layout |
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|
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\end_inset |
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|
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include |
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\family typewriter |
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emacs |
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\family default |
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|
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\begin_inset Index idx |
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status collapsed |
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\begin_layout Plain Layout |
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emacs |
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\end_layout |
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|
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\end_inset |
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|
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and |
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\family typewriter |
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gedit |
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\begin_inset Index idx |
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status collapsed |
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|
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\begin_layout Plain Layout |
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gedit |
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\end_layout |
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|
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\end_inset |
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|
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|
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\family default |
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on Linux, and Notepad |
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\begin_inset Index idx |
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status collapsed |
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|
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\begin_layout Plain Layout |
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Notepad |
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\end_layout |
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|
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\end_inset |
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|
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and TextPad |
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\begin_inset Index idx |
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status collapsed |
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\begin_layout Plain Layout |
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TextPad |
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\end_layout |
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|
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\end_inset |
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|
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on Windows. |
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We shall discuss editors shortly.) |
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\end_layout |
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|
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\begin_layout Standard |
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We need first to decide the parts to our model. |
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In this case we know that we need the variables |
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\begin_inset Index idx |
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status collapsed |
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|
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\begin_layout Plain Layout |
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variables, vessel |
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\end_layout |
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|
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\end_inset |
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|
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listed in Table |
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\begin_inset CommandInset ref |
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LatexCommand ref |
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reference "tab:model1.variablesVesselModel" |
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|
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\end_inset |
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|
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|
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\noun off |
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. |
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We readily fill in the first three columns in this table. |
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We shall discuss the entry in the last column in a moment. |
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\end_layout |
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|
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\begin_layout Plain Layout |
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Variables required for model |
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\begin_inset CommandInset label |
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LatexCommand label |
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name "tab:model1.variablesVesselModel" |
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|
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\end_inset |
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\end_layout |
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\end_inset |
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<lyxtabular version="3" rows="5" columns="4"> |
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<features rotate="0" tabularvalignment="middle"> |
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<column alignment="center" valignment="top"> |
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<column alignment="center" valignment="top"> |
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<column alignment="center" valignment="top"> |
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<column alignment="center" valignment="top" width="1in"> |
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<row> |
724 |
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> |
725 |
\begin_inset Text |
726 |
|
727 |
\begin_layout Plain Layout |
728 |
Symbol |
729 |
\end_layout |
730 |
|
731 |
\end_inset |
732 |
</cell> |
733 |
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> |
734 |
\begin_inset Text |
735 |
|
736 |
\begin_layout Plain Layout |
737 |
Meaning |
738 |
\end_layout |
739 |
|
740 |
\end_inset |
741 |
</cell> |
742 |
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> |
743 |
\begin_inset Text |
744 |
|
745 |
\begin_layout Plain Layout |
746 |
Typical Units |
747 |
\end_layout |
748 |
|
749 |
\end_inset |
750 |
</cell> |
751 |
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none"> |
752 |
\begin_inset Text |
753 |
|
754 |
\begin_layout Plain Layout |
755 |
ASCEND variable type |
756 |
\end_layout |
757 |
|
758 |
\end_inset |
759 |
</cell> |
760 |
</row> |
761 |
<row> |
762 |
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
763 |
\begin_inset Text |
764 |
|
765 |
\begin_layout Plain Layout |
766 |
|
767 |
\family typewriter |
768 |
D |
769 |
\end_layout |
770 |
|
771 |
\end_inset |
772 |
</cell> |
773 |
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
774 |
\begin_inset Text |
775 |
|
776 |
\begin_layout Plain Layout |
777 |
vessel diameter |
778 |
\end_layout |
779 |
|
780 |
\end_inset |
781 |
</cell> |
782 |
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
783 |
\begin_inset Text |
784 |
|
785 |
\begin_layout Plain Layout |
786 |
m, ft |
787 |
\end_layout |
788 |
|
789 |
\end_inset |
790 |
</cell> |
791 |
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
792 |
\begin_inset Text |
793 |
|
794 |
\begin_layout Plain Layout |
795 |
|
796 |
\family typewriter |
797 |
length |
798 |
\end_layout |
799 |
|
800 |
\end_inset |
801 |
</cell> |
802 |
</row> |
803 |
<row> |
804 |
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
805 |
\begin_inset Text |
806 |
|
807 |
\begin_layout Plain Layout |
808 |
|
809 |
\family typewriter |
810 |
H |
811 |
\end_layout |
812 |
|
813 |
\end_inset |
814 |
</cell> |
815 |
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
816 |
\begin_inset Text |
817 |
|
818 |
\begin_layout Plain Layout |
819 |
vessel height |
820 |
\end_layout |
821 |
|
822 |
\end_inset |
823 |
</cell> |
824 |
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
825 |
\begin_inset Text |
826 |
|
827 |
\begin_layout Plain Layout |
828 |
m, ft |
829 |
\end_layout |
830 |
|
831 |
\end_inset |
832 |
</cell> |
833 |
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
834 |
\begin_inset Text |
835 |
|
836 |
\begin_layout Plain Layout |
837 |
|
838 |
\family typewriter |
839 |
length |
840 |
\end_layout |
841 |
|
842 |
\end_inset |
843 |
</cell> |
844 |
</row> |
845 |
<row> |
846 |
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
847 |
\begin_inset Text |
848 |
|
849 |
\begin_layout Plain Layout |
850 |
|
851 |
\family typewriter |
852 |
wall_thickness |
853 |
\end_layout |
854 |
|
855 |
\end_inset |
856 |
</cell> |
857 |
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
858 |
\begin_inset Text |
859 |
|
860 |
\begin_layout Plain Layout |
861 |
wall thickness |
862 |
\end_layout |
863 |
|
864 |
\end_inset |
865 |
</cell> |
866 |
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
867 |
\begin_inset Text |
868 |
|
869 |
\begin_layout Plain Layout |
870 |
mm, in |
871 |
\end_layout |
872 |
|
873 |
\end_inset |
874 |
</cell> |
875 |
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
876 |
\begin_inset Text |
877 |
|
878 |
\begin_layout Plain Layout |
879 |
|
880 |
\family typewriter |
881 |
length |
882 |
\end_layout |
883 |
|
884 |
\end_inset |
885 |
</cell> |
886 |
</row> |
887 |
<row> |
888 |
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> |
889 |
\begin_inset Text |
890 |
|
891 |
\begin_layout Plain Layout |
892 |
|
893 |
\family typewriter |
894 |
metal_density |
895 |
\end_layout |
896 |
|
897 |
\end_inset |
898 |
</cell> |
899 |
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> |
900 |
\begin_inset Text |
901 |
|
902 |
\begin_layout Plain Layout |
903 |
metal density |
904 |
\end_layout |
905 |
|
906 |
\end_inset |
907 |
</cell> |
908 |
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> |
909 |
\begin_inset Text |
910 |
|
911 |
\begin_layout Plain Layout |
912 |
kg/m |
913 |
\begin_inset Formula $^{\textrm{3}}$ |
914 |
\end_inset |
915 |
|
916 |
, lbm/ft |
917 |
\begin_inset Formula $^{\textrm{3}}$ |
918 |
\end_inset |
919 |
|
920 |
|
921 |
\end_layout |
922 |
|
923 |
\end_inset |
924 |
</cell> |
925 |
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none"> |
926 |
\begin_inset Text |
927 |
|
928 |
\begin_layout Plain Layout |
929 |
|
930 |
\family typewriter |
931 |
mass_density |
932 |
\end_layout |
933 |
|
934 |
\end_inset |
935 |
</cell> |
936 |
</row> |
937 |
</lyxtabular> |
938 |
|
939 |
\end_inset |
940 |
|
941 |
|
942 |
\end_layout |
943 |
|
944 |
\end_inset |
945 |
|
946 |
|
947 |
\end_layout |
948 |
|
949 |
\begin_layout Standard |
950 |
We will be computing the masses for the metal in the side wall and in the |
951 |
ends for this vessel. |
952 |
As this is a thin-walled vessel, we shall compute the volume of metal as |
953 |
the area of the walls times the wall thickness. |
954 |
The following equations allow us to compute the required areas |
955 |
\end_layout |
956 |
|
957 |
\begin_layout Standard |
958 |
\begin_inset Formula |
959 |
\begin{equation} |
960 |
\mathrm{side\, wall\, area}=\pi DH\label{eq:model1.side-wall-area} |
961 |
\end{equation} |
962 |
|
963 |
\end_inset |
964 |
|
965 |
|
966 |
\end_layout |
967 |
|
968 |
\begin_layout Standard |
969 |
\begin_inset Formula |
970 |
\begin{equation} |
971 |
\mathrm{single\, end\, area}=\frac{\pi D^{2}}{4}\label{eq:model1.single-end-area} |
972 |
\end{equation} |
973 |
|
974 |
\end_inset |
975 |
|
976 |
|
977 |
\end_layout |
978 |
|
979 |
\begin_layout Standard |
980 |
We should be interested in the volume of the vessel, which we compute as: |
981 |
\end_layout |
982 |
|
983 |
\begin_layout Standard |
984 |
\begin_inset Formula |
985 |
\begin{equation} |
986 |
\mathrm{vessel\, volume}=\mathrm{single\, end\, area}\times H\label{eq:model1.vessel-volume} |
987 |
\end{equation} |
988 |
|
989 |
\end_inset |
990 |
|
991 |
|
992 |
\end_layout |
993 |
|
994 |
\begin_layout Standard |
995 |
We add the variables in Table |
996 |
\begin_inset CommandInset ref |
997 |
LatexCommand ref |
998 |
reference "tab:model1.moreVariablesVessel" |
999 |
|
1000 |
\end_inset |
1001 |
|
1002 |
|
1003 |
\noun off |
1004 |
to our list. |
1005 |
\end_layout |
1006 |
|
1007 |
\begin_layout Standard |
1008 |
\begin_inset Float table |
1009 |
wide false |
1010 |
sideways false |
1011 |
status open |
1012 |
|
1013 |
\begin_layout Plain Layout |
1014 |
\begin_inset Caption Standard |
1015 |
|
1016 |
\begin_layout Plain Layout |
1017 |
Some more variables |
1018 |
\begin_inset Index idx |
1019 |
status collapsed |
1020 |
|
1021 |
\begin_layout Plain Layout |
1022 |
variables, vessel |
1023 |
\end_layout |
1024 |
|
1025 |
\end_inset |
1026 |
|
1027 |
required for vessel model |
1028 |
\begin_inset CommandInset label |
1029 |
LatexCommand label |
1030 |
name "tab:model1.moreVariablesVessel" |
1031 |
|
1032 |
\end_inset |
1033 |
|
1034 |
|
1035 |
\end_layout |
1036 |
|
1037 |
\end_inset |
1038 |
|
1039 |
|
1040 |
\end_layout |
1041 |
|
1042 |
\begin_layout Plain Layout |
1043 |
\begin_inset Tabular |
1044 |
<lyxtabular version="3" rows="6" columns="4"> |
1045 |
<features rotate="0" tabularvalignment="middle"> |
1046 |
<column alignment="center" valignment="top"> |
1047 |
<column alignment="center" valignment="top" width="1.5in"> |
1048 |
<column alignment="center" valignment="top"> |
1049 |
<column alignment="center" valignment="top" width="1in"> |
1050 |
<row> |
1051 |
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> |
1052 |
\begin_inset Text |
1053 |
|
1054 |
\begin_layout Plain Layout |
1055 |
Symbol |
1056 |
\end_layout |
1057 |
|
1058 |
\end_inset |
1059 |
</cell> |
1060 |
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> |
1061 |
\begin_inset Text |
1062 |
|
1063 |
\begin_layout Plain Layout |
1064 |
Meaning |
1065 |
\end_layout |
1066 |
|
1067 |
\end_inset |
1068 |
</cell> |
1069 |
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> |
1070 |
\begin_inset Text |
1071 |
|
1072 |
\begin_layout Plain Layout |
1073 |
Typical Units |
1074 |
\end_layout |
1075 |
|
1076 |
\end_inset |
1077 |
</cell> |
1078 |
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none"> |
1079 |
\begin_inset Text |
1080 |
|
1081 |
\begin_layout Plain Layout |
1082 |
ASCEND variable type |
1083 |
\end_layout |
1084 |
|
1085 |
\end_inset |
1086 |
</cell> |
1087 |
</row> |
1088 |
<row> |
1089 |
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
1090 |
\begin_inset Text |
1091 |
|
1092 |
\begin_layout Plain Layout |
1093 |
|
1094 |
\family typewriter |
1095 |
side_area |
1096 |
\end_layout |
1097 |
|
1098 |
\end_inset |
1099 |
</cell> |
1100 |
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
1101 |
\begin_inset Text |
1102 |
|
1103 |
\begin_layout Plain Layout |
1104 |
area in the sidewall of the vessel |
1105 |
\end_layout |
1106 |
|
1107 |
\end_inset |
1108 |
</cell> |
1109 |
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
1110 |
\begin_inset Text |
1111 |
|
1112 |
\begin_layout Plain Layout |
1113 |
m |
1114 |
\begin_inset Formula $^{\textrm{2}}$ |
1115 |
\end_inset |
1116 |
|
1117 |
, ft |
1118 |
\begin_inset Formula $^{\textrm{2}}$ |
1119 |
\end_inset |
1120 |
|
1121 |
|
1122 |
\end_layout |
1123 |
|
1124 |
\end_inset |
1125 |
</cell> |
1126 |
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
1127 |
\begin_inset Text |
1128 |
|
1129 |
\begin_layout Plain Layout |
1130 |
|
1131 |
\family typewriter |
1132 |
area |
1133 |
\end_layout |
1134 |
|
1135 |
\end_inset |
1136 |
</cell> |
1137 |
</row> |
1138 |
<row> |
1139 |
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
1140 |
\begin_inset Text |
1141 |
|
1142 |
\begin_layout Plain Layout |
1143 |
|
1144 |
\family typewriter |
1145 |
end_area |
1146 |
\end_layout |
1147 |
|
1148 |
\end_inset |
1149 |
</cell> |
1150 |
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
1151 |
\begin_inset Text |
1152 |
|
1153 |
\begin_layout Plain Layout |
1154 |
total area iin the ends of the vessel |
1155 |
\end_layout |
1156 |
|
1157 |
\end_inset |
1158 |
</cell> |
1159 |
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
1160 |
\begin_inset Text |
1161 |
|
1162 |
\begin_layout Plain Layout |
1163 |
m |
1164 |
\begin_inset Formula $^{\textrm{2}}$ |
1165 |
\end_inset |
1166 |
|
1167 |
, ft |
1168 |
\begin_inset Formula $^{\textrm{2}}$ |
1169 |
\end_inset |
1170 |
|
1171 |
|
1172 |
\end_layout |
1173 |
|
1174 |
\end_inset |
1175 |
</cell> |
1176 |
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
1177 |
\begin_inset Text |
1178 |
|
1179 |
\begin_layout Plain Layout |
1180 |
|
1181 |
\family typewriter |
1182 |
area |
1183 |
\end_layout |
1184 |
|
1185 |
\end_inset |
1186 |
</cell> |
1187 |
</row> |
1188 |
<row> |
1189 |
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
1190 |
\begin_inset Text |
1191 |
|
1192 |
\begin_layout Plain Layout |
1193 |
|
1194 |
\family typewriter |
1195 |
vessel_volume |
1196 |
\end_layout |
1197 |
|
1198 |
\end_inset |
1199 |
</cell> |
1200 |
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
1201 |
\begin_inset Text |
1202 |
|
1203 |
\begin_layout Plain Layout |
1204 |
volume of the vessel |
1205 |
\end_layout |
1206 |
|
1207 |
\end_inset |
1208 |
</cell> |
1209 |
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
1210 |
\begin_inset Text |
1211 |
|
1212 |
\begin_layout Plain Layout |
1213 |
m |
1214 |
\begin_inset Formula $^{3}$ |
1215 |
\end_inset |
1216 |
|
1217 |
, ft |
1218 |
\begin_inset Formula $^{\textrm{3}}$ |
1219 |
\end_inset |
1220 |
|
1221 |
|
1222 |
\end_layout |
1223 |
|
1224 |
\end_inset |
1225 |
</cell> |
1226 |
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
1227 |
\begin_inset Text |
1228 |
|
1229 |
\begin_layout Plain Layout |
1230 |
|
1231 |
\family typewriter |
1232 |
volume |
1233 |
\end_layout |
1234 |
|
1235 |
\end_inset |
1236 |
</cell> |
1237 |
</row> |
1238 |
<row> |
1239 |
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
1240 |
\begin_inset Text |
1241 |
|
1242 |
\begin_layout Plain Layout |
1243 |
|
1244 |
\family typewriter |
1245 |
metal_volume |
1246 |
\end_layout |
1247 |
|
1248 |
\end_inset |
1249 |
</cell> |
1250 |
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
1251 |
\begin_inset Text |
1252 |
|
1253 |
\begin_layout Plain Layout |
1254 |
total volume of metal in the walls |
1255 |
\end_layout |
1256 |
|
1257 |
\end_inset |
1258 |
</cell> |
1259 |
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
1260 |
\begin_inset Text |
1261 |
|
1262 |
\begin_layout Plain Layout |
1263 |
m |
1264 |
\begin_inset Formula $^{3}$ |
1265 |
\end_inset |
1266 |
|
1267 |
, ft |
1268 |
\begin_inset Formula $^{\textrm{3}}$ |
1269 |
\end_inset |
1270 |
|
1271 |
|
1272 |
\end_layout |
1273 |
|
1274 |
\end_inset |
1275 |
</cell> |
1276 |
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
1277 |
\begin_inset Text |
1278 |
|
1279 |
\begin_layout Plain Layout |
1280 |
|
1281 |
\family typewriter |
1282 |
volume |
1283 |
\end_layout |
1284 |
|
1285 |
\end_inset |
1286 |
</cell> |
1287 |
</row> |
1288 |
<row> |
1289 |
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> |
1290 |
\begin_inset Text |
1291 |
|
1292 |
\begin_layout Plain Layout |
1293 |
|
1294 |
\family typewriter |
1295 |
metal_mass |
1296 |
\end_layout |
1297 |
|
1298 |
\end_inset |
1299 |
</cell> |
1300 |
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> |
1301 |
\begin_inset Text |
1302 |
|
1303 |
\begin_layout Plain Layout |
1304 |
total mass of the metal in the walls of the vessel |
1305 |
\end_layout |
1306 |
|
1307 |
\end_inset |
1308 |
</cell> |
1309 |
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> |
1310 |
\begin_inset Text |
1311 |
|
1312 |
\begin_layout Plain Layout |
1313 |
kg, lbm |
1314 |
\end_layout |
1315 |
|
1316 |
\end_inset |
1317 |
</cell> |
1318 |
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none"> |
1319 |
\begin_inset Text |
1320 |
|
1321 |
\begin_layout Plain Layout |
1322 |
|
1323 |
\family typewriter |
1324 |
mass |
1325 |
\end_layout |
1326 |
|
1327 |
\end_inset |
1328 |
</cell> |
1329 |
</row> |
1330 |
</lyxtabular> |
1331 |
|
1332 |
\end_inset |
1333 |
|
1334 |
|
1335 |
\end_layout |
1336 |
|
1337 |
\end_inset |
1338 |
|
1339 |
|
1340 |
\end_layout |
1341 |
|
1342 |
\begin_layout Standard |
1343 |
We believe that no one should create a model of any consequence without |
1344 |
worrying about the units for expressing the variables within it. |
1345 |
We consider that to be a commandment handed down from somewhere on high; |
1346 |
however, we know that others do not believe as we do. |
1347 |
Grant us our beliefs. |
1348 |
We have created in the ASCEND system a library of variable and constant |
1349 |
types called atoms.a4l |
1350 |
\begin_inset Index idx |
1351 |
status collapsed |
1352 |
|
1353 |
\begin_layout Plain Layout |
1354 |
atoms.a4l |
1355 |
\end_layout |
1356 |
|
1357 |
\end_inset |
1358 |
|
1359 |
. |
1360 |
\end_layout |
1361 |
|
1362 |
\begin_layout Standard |
1363 |
The file type " |
1364 |
\family typewriter |
1365 |
.a4l |
1366 |
\begin_inset Index idx |
1367 |
status collapsed |
1368 |
|
1369 |
\begin_layout Plain Layout |
1370 |
a4l |
1371 |
\end_layout |
1372 |
|
1373 |
\end_inset |
1374 |
|
1375 |
|
1376 |
\family default |
1377 |
" designates it to be an ASCEND IV library file |
1378 |
\begin_inset Index idx |
1379 |
status collapsed |
1380 |
|
1381 |
\begin_layout Plain Layout |
1382 |
library file |
1383 |
\end_layout |
1384 |
|
1385 |
\end_inset |
1386 |
|
1387 |
. |
1388 |
Double-click on this link to see the approximately 150 different types |
1389 |
ranging from universal constants |
1390 |
\begin_inset Index idx |
1391 |
status collapsed |
1392 |
|
1393 |
\begin_layout Plain Layout |
1394 |
universal constants |
1395 |
\end_layout |
1396 |
|
1397 |
\end_inset |
1398 |
|
1399 |
such as |
1400 |
\begin_inset Formula $\pi$ |
1401 |
\end_inset |
1402 |
|
1403 |
(=3.14159...) and |
1404 |
\begin_inset Formula $e$ |
1405 |
\end_inset |
1406 |
|
1407 |
(=2.718...) to |
1408 |
\family typewriter |
1409 |
length |
1410 |
\family default |
1411 |
, |
1412 |
\family typewriter |
1413 |
mass |
1414 |
\family default |
1415 |
and |
1416 |
\family typewriter |
1417 |
angle |
1418 |
\family default |
1419 |
. |
1420 |
If we have not created one that you need, you can use this library of types |
1421 |
to see how to construct one for yourself and add it to your file of type |
1422 |
definitions. |
1423 |
You will find detailed instructions for how to make your own variable type |
1424 |
library in Chapter |
1425 |
\begin_inset space ~ |
1426 |
\end_inset |
1427 |
|
1428 |
|
1429 |
\begin_inset CommandInset ref |
1430 |
LatexCommand vref |
1431 |
reference "cha:atoms" |
1432 |
|
1433 |
\end_inset |
1434 |
|
1435 |
. |
1436 |
\end_layout |
1437 |
|
1438 |
\begin_layout Standard |
1439 |
\begin_inset Marginal |
1440 |
status collapsed |
1441 |
|
1442 |
\begin_layout Plain Layout |
1443 |
type definition library for variables and constants |
1444 |
\end_layout |
1445 |
|
1446 |
\end_inset |
1447 |
|
1448 |
ASCEND considers variable and constant types to be elementary or "atomic" |
1449 |
to the system. |
1450 |
These type definitions can contain only attributes for variables and constants. |
1451 |
They cannot contain equations, for example. |
1452 |
Thus ASCEND calls such a type definition an atom rather than a model. |
1453 |
Figure |
1454 |
\begin_inset CommandInset ref |
1455 |
LatexCommand ref |
1456 |
reference "fig:model1.atomVolume" |
1457 |
|
1458 |
\end_inset |
1459 |
|
1460 |
|
1461 |
\noun off |
1462 |
illustrates the definition for the type volume. |
1463 |
|
1464 |
\end_layout |
1465 |
|
1466 |
\begin_layout Standard |
1467 |
\begin_inset Float figure |
1468 |
wide false |
1469 |
sideways false |
1470 |
status open |
1471 |
|
1472 |
\begin_layout Plain Layout |
1473 |
\begin_inset Index idx |
1474 |
status collapsed |
1475 |
|
1476 |
\begin_layout Plain Layout |
1477 |
ATOM |
1478 |
\end_layout |
1479 |
|
1480 |
\end_inset |
1481 |
|
1482 |
|
1483 |
\begin_inset ERT |
1484 |
status open |
1485 |
|
1486 |
\begin_layout Plain Layout |
1487 |
|
1488 |
|
1489 |
\backslash |
1490 |
lstset{language=ASCEND} |
1491 |
\end_layout |
1492 |
|
1493 |
\begin_layout Plain Layout |
1494 |
|
1495 |
|
1496 |
\backslash |
1497 |
begin{lstlisting} |
1498 |
\end_layout |
1499 |
|
1500 |
\begin_layout Plain Layout |
1501 |
|
1502 |
ATOM volume REFINES solver_var |
1503 |
\end_layout |
1504 |
|
1505 |
\begin_layout Plain Layout |
1506 |
|
1507 |
DIMENSION L^3 |
1508 |
\end_layout |
1509 |
|
1510 |
\begin_layout Plain Layout |
1511 |
|
1512 |
DEFAULT 100.0{ft^3}; |
1513 |
\end_layout |
1514 |
|
1515 |
\begin_layout Plain Layout |
1516 |
|
1517 |
lower_bound := 0.0{ft^3}; |
1518 |
\end_layout |
1519 |
|
1520 |
\begin_layout Plain Layout |
1521 |
|
1522 |
upper_bound := 1e50{ft^3}; |
1523 |
\end_layout |
1524 |
|
1525 |
\begin_layout Plain Layout |
1526 |
|
1527 |
nominal := 100.0{ft^3}; |
1528 |
\end_layout |
1529 |
|
1530 |
\begin_layout Plain Layout |
1531 |
|
1532 |
END volume; |
1533 |
\end_layout |
1534 |
|
1535 |
\begin_layout Plain Layout |
1536 |
|
1537 |
|
1538 |
\backslash |
1539 |
end{lstlisting} |
1540 |
\end_layout |
1541 |
|
1542 |
\begin_layout Plain Layout |
1543 |
|
1544 |
\end_layout |
1545 |
|
1546 |
\end_inset |
1547 |
|
1548 |
|
1549 |
\end_layout |
1550 |
|
1551 |
\begin_layout Plain Layout |
1552 |
\begin_inset Caption Standard |
1553 |
|
1554 |
\begin_layout Plain Layout |
1555 |
A typical type definition, called an atom, used to define variable and constant |
1556 |
types |
1557 |
\begin_inset CommandInset label |
1558 |
LatexCommand label |
1559 |
name "fig:model1.atomVolume" |
1560 |
|
1561 |
\end_inset |
1562 |
|
1563 |
|
1564 |
\end_layout |
1565 |
|
1566 |
\end_inset |
1567 |
|
1568 |
|
1569 |
\end_layout |
1570 |
|
1571 |
\end_inset |
1572 |
|
1573 |
|
1574 |
\end_layout |
1575 |
|
1576 |
\begin_layout Standard |
1577 |
The definition starts by stating that volume is a specialization of |
1578 |
\begin_inset Index idx |
1579 |
status collapsed |
1580 |
|
1581 |
\begin_layout Plain Layout |
1582 |
solver |
1583 |
\begin_inset ERT |
1584 |
status collapsed |
1585 |
|
1586 |
\begin_layout Plain Layout |
1587 |
|
1588 |
|
1589 |
\backslash |
1590 |
_ |
1591 |
\end_layout |
1592 |
|
1593 |
\end_inset |
1594 |
|
1595 |
var |
1596 |
\end_layout |
1597 |
|
1598 |
\end_inset |
1599 |
|
1600 |
|
1601 |
\family typewriter |
1602 |
solver_var |
1603 |
\family default |
1604 |
. |
1605 |
The type |
1606 |
\family typewriter |
1607 |
solver_var |
1608 |
\family default |
1609 |
refines a base type in the system known as |
1610 |
\family typewriter |
1611 |
real |
1612 |
\family default |
1613 |
|
1614 |
\begin_inset Index idx |
1615 |
status collapsed |
1616 |
|
1617 |
\begin_layout Plain Layout |
1618 |
real |
1619 |
\end_layout |
1620 |
|
1621 |
\end_inset |
1622 |
|
1623 |
and adds several attributes to it that a nonlinear equation solver may |
1624 |
need, such as a lower and upper bounds, a 'fixed' flag, and so forth. |
1625 |
|
1626 |
\end_layout |
1627 |
|
1628 |
\begin_layout Standard |
1629 |
\begin_inset Marginal |
1630 |
status collapsed |
1631 |
|
1632 |
\begin_layout Plain Layout |
1633 |
dimensions |
1634 |
\begin_inset Index idx |
1635 |
status collapsed |
1636 |
|
1637 |
\begin_layout Plain Layout |
1638 |
dimensions |
1639 |
\end_layout |
1640 |
|
1641 |
\end_inset |
1642 |
|
1643 |
and units |
1644 |
\begin_inset Index idx |
1645 |
status collapsed |
1646 |
|
1647 |
\begin_layout Plain Layout |
1648 |
units |
1649 |
\end_layout |
1650 |
|
1651 |
\end_inset |
1652 |
|
1653 |
in ASCEND. |
1654 |
|
1655 |
\end_layout |
1656 |
|
1657 |
\end_inset |
1658 |
|
1659 |
The type definition for volume states that volume has dimensionality of |
1660 |
length to the power 3 ( |
1661 |
\family typewriter |
1662 |
L^3 |
1663 |
\family default |
1664 |
) where L is one of the 10 dimensions supported by ASCEND (see |
1665 |
\noun off |
1666 |
in ASCEND Syntax document for the 10 dimensions defined within the ASCEND |
1667 |
language). |
1668 |
\end_layout |
1669 |
|
1670 |
\begin_layout Standard |
1671 |
One may express the value for a volume using any units which are consistent |
1672 |
with the dimensionality of |
1673 |
\family typewriter |
1674 |
L^3 |
1675 |
\family default |
1676 |
, such as |
1677 |
\family typewriter |
1678 |
{ft^3} |
1679 |
\family default |
1680 |
, |
1681 |
\family typewriter |
1682 |
{m^3} |
1683 |
\family default |
1684 |
, |
1685 |
\family typewriter |
1686 |
{gal} |
1687 |
\family default |
1688 |
, or even |
1689 |
\family typewriter |
1690 |
{mile^4/mm} |
1691 |
\family default |
1692 |
. |
1693 |
Setting the lower bound to |
1694 |
\family typewriter |
1695 |
0 {ft^3} |
1696 |
\family default |
1697 |
says volume must be a nonnegative number. |
1698 |
ASCEND used the nominal value for scaling a variable of type volume when |
1699 |
solving, here |
1700 |
\begin_inset Formula $100\,\mathrm{ft}^{3}$ |
1701 |
\end_inset |
1702 |
|
1703 |
. |
1704 |
\end_layout |
1705 |
|
1706 |
\begin_layout Standard |
1707 |
One may change the values for the bounds, default and nominal values at |
1708 |
any time. |
1709 |
\end_layout |
1710 |
|
1711 |
\begin_layout Standard |
1712 |
We now can understand the last column in Table |
1713 |
\begin_inset CommandInset ref |
1714 |
LatexCommand ref |
1715 |
reference "tab:model1.variablesVesselModel" |
1716 |
|
1717 |
\end_inset |
1718 |
|
1719 |
|
1720 |
\noun off |
1721 |
and |
1722 |
\noun default |
1723 |
Table |
1724 |
\noun off |
1725 |
|
1726 |
\begin_inset CommandInset ref |
1727 |
LatexCommand ref |
1728 |
reference "tab:model1.moreVariablesVessel" |
1729 |
|
1730 |
\end_inset |
1731 |
|
1732 |
. |
1733 |
For each variable or constant in the system, we have identified its type |
1734 |
in the file |
1735 |
\family typewriter |
1736 |
\noun default |
1737 |
atoms.a4l |
1738 |
\family default |
1739 |
\noun off |
1740 |
. |
1741 |
That is, we looked in this file for the type definition that corresponded |
1742 |
to the variable we were defining and listed that type here. |
1743 |
This task is not as onerous as it seems. |
1744 |
As we shall see later, we provide a tool to find for you all atom types |
1745 |
that correspond to a particular set of units, e.g, |
1746 |
\family typewriter |
1747 |
\noun default |
1748 |
ft^3 |
1749 |
\family default |
1750 |
\noun off |
1751 |
-- i.e., the computer will do the searching for you. |
1752 |
\end_layout |
1753 |
|
1754 |
\begin_layout Standard |
1755 |
In Figure |
1756 |
\begin_inset CommandInset ref |
1757 |
LatexCommand ref |
1758 |
reference "fig:model1.universalConstant" |
1759 |
|
1760 |
\end_inset |
1761 |
|
1762 |
|
1763 |
\noun off |
1764 |
we see the definition of one of the universal constants contained in |
1765 |
\family typewriter |
1766 |
\noun default |
1767 |
atoms.a4l |
1768 |
\family default |
1769 |
\noun off |
1770 |
. |
1771 |
This definition is very short; it gives the name of the type |
1772 |
\family typewriter |
1773 |
\noun default |
1774 |
circle_constant |
1775 |
\family default |
1776 |
\noun off |
1777 |
|
1778 |
\begin_inset Index idx |
1779 |
status collapsed |
1780 |
|
1781 |
\begin_layout Plain Layout |
1782 |
circle |
1783 |
\begin_inset ERT |
1784 |
status collapsed |
1785 |
|
1786 |
\begin_layout Plain Layout |
1787 |
|
1788 |
|
1789 |
\backslash |
1790 |
_ |
1791 |
\end_layout |
1792 |
|
1793 |
\end_inset |
1794 |
|
1795 |
constant |
1796 |
\end_layout |
1797 |
|
1798 |
\end_inset |
1799 |
|
1800 |
, that it refines |
1801 |
\family typewriter |
1802 |
\noun default |
1803 |
real_constant |
1804 |
\family default |
1805 |
\noun off |
1806 |
|
1807 |
\begin_inset Index idx |
1808 |
status collapsed |
1809 |
|
1810 |
\begin_layout Plain Layout |
1811 |
real |
1812 |
\begin_inset ERT |
1813 |
status collapsed |
1814 |
|
1815 |
\begin_layout Plain Layout |
1816 |
|
1817 |
|
1818 |
\backslash |
1819 |
_ |
1820 |
\end_layout |
1821 |
|
1822 |
\end_inset |
1823 |
|
1824 |
constant |
1825 |
\end_layout |
1826 |
|
1827 |
\end_inset |
1828 |
|
1829 |
and that it has the value |
1830 |
\family typewriter |
1831 |
\noun default |
1832 |
1 {PI |
1833 |
\begin_inset Index idx |
1834 |
status collapsed |
1835 |
|
1836 |
\begin_layout Plain Layout |
1837 |
PI |
1838 |
\end_layout |
1839 |
|
1840 |
\end_inset |
1841 |
|
1842 |
} |
1843 |
\family default |
1844 |
\noun off |
1845 |
|
1846 |
\begin_inset Index idx |
1847 |
status collapsed |
1848 |
|
1849 |
\begin_layout Plain Layout |
1850 |
\begin_inset ERT |
1851 |
status collapsed |
1852 |
|
1853 |
\begin_layout Plain Layout |
1854 |
|
1855 |
|
1856 |
\backslash |
1857 |
{ |
1858 |
\end_layout |
1859 |
|
1860 |
\end_inset |
1861 |
|
1862 |
PI |
1863 |
\begin_inset ERT |
1864 |
status collapsed |
1865 |
|
1866 |
\begin_layout Plain Layout |
1867 |
|
1868 |
|
1869 |
\backslash |
1870 |
} |
1871 |
\end_layout |
1872 |
|
1873 |
\end_inset |
1874 |
|
1875 |
|
1876 |
\end_layout |
1877 |
|
1878 |
\end_inset |
1879 |
|
1880 |
where the internal conversion needed for |
1881 |
\family typewriter |
1882 |
\noun default |
1883 |
{PI} |
1884 |
\family default |
1885 |
\noun off |
1886 |
is defined in the file defining the built-in units in ASCEND. |
1887 |
One can add more units if desired at any time to ASCEND by defining one |
1888 |
or more personal units files ( |
1889 |
\noun default |
1890 |
Chapter |
1891 |
\noun off |
1892 |
|
1893 |
\begin_inset CommandInset ref |
1894 |
LatexCommand vref |
1895 |
reference "cha:units" |
1896 |
|
1897 |
\end_inset |
1898 |
|
1899 |
|
1900 |
\noun default |
1901 |
|
1902 |
\noun off |
1903 |
tells you how to do this). |
1904 |
\end_layout |
1905 |
|
1906 |
\begin_layout Standard |
1907 |
\begin_inset Marginal |
1908 |
status collapsed |
1909 |
|
1910 |
\begin_layout Plain Layout |
1911 |
universal constant |
1912 |
\begin_inset Index idx |
1913 |
status collapsed |
1914 |
|
1915 |
\begin_layout Plain Layout |
1916 |
universal constant |
1917 |
\end_layout |
1918 |
|
1919 |
\end_inset |
1920 |
|
1921 |
definition |
1922 |
\end_layout |
1923 |
|
1924 |
\end_inset |
1925 |
|
1926 |
|
1927 |
\begin_inset Float figure |
1928 |
wide false |
1929 |
sideways false |
1930 |
status open |
1931 |
|
1932 |
\begin_layout LyX-Code |
1933 |
\begin_inset ERT |
1934 |
status open |
1935 |
|
1936 |
\begin_layout Plain Layout |
1937 |
|
1938 |
|
1939 |
\backslash |
1940 |
begin{ascend} |
1941 |
\end_layout |
1942 |
|
1943 |
\begin_layout Plain Layout |
1944 |
|
1945 |
UNIVERSAL CONSTANT circle_constant |
1946 |
\end_layout |
1947 |
|
1948 |
\begin_layout Plain Layout |
1949 |
|
1950 |
REFINES real_constant :== 1{PI}; |
1951 |
\end_layout |
1952 |
|
1953 |
\begin_layout Plain Layout |
1954 |
|
1955 |
|
1956 |
\backslash |
1957 |
end{ascend} |
1958 |
\end_layout |
1959 |
|
1960 |
\end_inset |
1961 |
|
1962 |
|
1963 |
\end_layout |
1964 |
|
1965 |
\begin_layout Plain Layout |
1966 |
\begin_inset Caption Standard |
1967 |
|
1968 |
\begin_layout Plain Layout |
1969 |
\begin_inset CommandInset label |
1970 |
LatexCommand label |
1971 |
name "fig:model1.universalConstant" |
1972 |
|
1973 |
\end_inset |
1974 |
|
1975 |
Type definition for |
1976 |
\family typewriter |
1977 |
circle_constant; |
1978 |
\family default |
1979 |
has value of |
1980 |
\family typewriter |
1981 |
1 {PI} |
1982 |
\family default |
1983 |
or 3.1415927 |
1984 |
\end_layout |
1985 |
|
1986 |
\end_inset |
1987 |
|
1988 |
|
1989 |
\end_layout |
1990 |
|
1991 |
\end_inset |
1992 |
|
1993 |
|
1994 |
\end_layout |
1995 |
|
1996 |
\begin_layout Standard |
1997 |
We shall in fact find this constant useful in our program, and we can either |
1998 |
introduce a constant with this value or simply use the value |
1999 |
\family typewriter |
2000 |
1{PI} |
2001 |
\family default |
2002 |
in our program. |
2003 |
We shall choose to do the latter. |
2004 |
\end_layout |
2005 |
|
2006 |
\begin_layout Standard |
2007 |
It is time to write our first version for the model, which we do in Figure |
2008 |
|
2009 |
\begin_inset CommandInset ref |
2010 |
LatexCommand ref |
2011 |
reference "fig:model1.modelVessel" |
2012 |
|
2013 |
\end_inset |
2014 |
|
2015 |
|
2016 |
\noun off |
2017 |
( |
2018 |
\noun default |
2019 |
available as |
2020 |
\begin_inset Index idx |
2021 |
status collapsed |
2022 |
|
2023 |
\begin_layout Plain Layout |
2024 |
vesselPlain.a4c |
2025 |
\end_layout |
2026 |
|
2027 |
\end_inset |
2028 |
|
2029 |
|
2030 |
\family typewriter |
2031 |
vesselPlain.a4c |
2032 |
\family default |
2033 |
in the ASCEND model library). |
2034 |
|
2035 |
\noun off |
2036 |
We first list any other files containing type definitions which this model |
2037 |
will use; here we list |
2038 |
\family typewriter |
2039 |
\noun default |
2040 |
"atoms.a4l" |
2041 |
\family default |
2042 |
\noun off |
2043 |
following the keyword |
2044 |
\family typewriter |
2045 |
\noun default |
2046 |
REQUIRE |
2047 |
\family default |
2048 |
\noun off |
2049 |
|
2050 |
\begin_inset Index idx |
2051 |
status collapsed |
2052 |
|
2053 |
\begin_layout Plain Layout |
2054 |
REQUIRE |
2055 |
\end_layout |
2056 |
|
2057 |
\end_inset |
2058 |
|
2059 |
. |
2060 |
ASCEND is sensitive to case so pay attention to where we use and do not |
2061 |
use capital letters. |
2062 |
Keywords are always capitalized. |
2063 |
Often for clarification we use capital letters in a name we use for a variable |
2064 |
or label (e.g., we use |
2065 |
\family typewriter |
2066 |
\noun default |
2067 |
D |
2068 |
\family default |
2069 |
\noun off |
2070 |
for diameter rather than |
2071 |
\family typewriter |
2072 |
\noun default |
2073 |
d |
2074 |
\family default |
2075 |
\noun off |
2076 |
). |
2077 |
Note that all ASCEND statements end with a semicolon (i.e., with |
2078 |
\noun default |
2079 |
' |
2080 |
\family typewriter |
2081 |
; |
2082 |
\family default |
2083 |
' |
2084 |
\noun off |
2085 |
) and not at the end of a line and that blank lines have no impact. |
2086 |
Comments are between opening and closing parenthesis/asterisk pairs, i.e., |
2087 |
' |
2088 |
\family typewriter |
2089 |
\noun default |
2090 |
(* |
2091 |
\family default |
2092 |
\noun off |
2093 |
' and ' |
2094 |
\family typewriter |
2095 |
\noun default |
2096 |
*) |
2097 |
\family default |
2098 |
\noun off |
2099 |
'. |
2100 |
\end_layout |
2101 |
|
2102 |
\begin_layout Standard |
2103 |
\begin_inset Marginal |
2104 |
status collapsed |
2105 |
|
2106 |
\begin_layout Plain Layout |
2107 |
the first version of the code for vessel |
2108 |
\end_layout |
2109 |
|
2110 |
\end_inset |
2111 |
|
2112 |
|
2113 |
\begin_inset Float figure |
2114 |
wide false |
2115 |
sideways false |
2116 |
status open |
2117 |
|
2118 |
\begin_layout LyX-Code |
2119 |
\begin_inset ERT |
2120 |
status open |
2121 |
|
2122 |
\begin_layout Plain Layout |
2123 |
|
2124 |
|
2125 |
\backslash |
2126 |
begin{ascend} |
2127 |
\end_layout |
2128 |
|
2129 |
\begin_layout Plain Layout |
2130 |
|
2131 |
REQUIRE "atoms.a4l"; |
2132 |
\end_layout |
2133 |
|
2134 |
\begin_layout Plain Layout |
2135 |
|
2136 |
MODEL vessel; |
2137 |
\end_layout |
2138 |
|
2139 |
\begin_layout Plain Layout |
2140 |
|
2141 |
(* variables *) |
2142 |
\end_layout |
2143 |
|
2144 |
\begin_layout Plain Layout |
2145 |
|
2146 |
side_area, end_area IS_A area; |
2147 |
\end_layout |
2148 |
|
2149 |
\begin_layout Plain Layout |
2150 |
|
2151 |
vessel_vol, wall_vol IS_A volume; |
2152 |
\end_layout |
2153 |
|
2154 |
\begin_layout Plain Layout |
2155 |
|
2156 |
wall_thickness, H, D IS_A distance; |
2157 |
\end_layout |
2158 |
|
2159 |
\begin_layout Plain Layout |
2160 |
|
2161 |
H_to_D_ratio IS_A factor; |
2162 |
\end_layout |
2163 |
|
2164 |
\begin_layout Plain Layout |
2165 |
|
2166 |
metal_density IS_A mass_density; |
2167 |
\end_layout |
2168 |
|
2169 |
\begin_layout Plain Layout |
2170 |
|
2171 |
metal_mass IS_A mass; |
2172 |
\end_layout |
2173 |
|
2174 |
\begin_layout Plain Layout |
2175 |
|
2176 |
\end_layout |
2177 |
|
2178 |
\begin_layout Plain Layout |
2179 |
|
2180 |
(* equations *) |
2181 |
\end_layout |
2182 |
|
2183 |
\begin_layout Plain Layout |
2184 |
|
2185 |
FlatEnds:end_area = 1{PI} * D^2 / 4; |
2186 |
\end_layout |
2187 |
|
2188 |
\begin_layout Plain Layout |
2189 |
|
2190 |
Sides:side_area = 1{PI} * D * H; |
2191 |
\end_layout |
2192 |
|
2193 |
\begin_layout Plain Layout |
2194 |
|
2195 |
Cylinder:vessel_vol = end_area * H; |
2196 |
\end_layout |
2197 |
|
2198 |
\begin_layout Plain Layout |
2199 |
|
2200 |
Metal_volume:(side_area + 2 * end_area) * |
2201 |
\end_layout |
2202 |
|
2203 |
\begin_layout Plain Layout |
2204 |
|
2205 |
wall_thickness = wall_vol; |
2206 |
\end_layout |
2207 |
|
2208 |
\begin_layout Plain Layout |
2209 |
|
2210 |
HD_definition:D * H_to_D_ratio = H; |
2211 |
\end_layout |
2212 |
|
2213 |
\begin_layout Plain Layout |
2214 |
|
2215 |
VesselMass:metal_mass = metal_density * wall_vol; |
2216 |
\end_layout |
2217 |
|
2218 |
\begin_layout Plain Layout |
2219 |
|
2220 |
END vessel; |
2221 |
\end_layout |
2222 |
|
2223 |
\begin_layout Plain Layout |
2224 |
|
2225 |
|
2226 |
\backslash |
2227 |
end{ascend} |
2228 |
\end_layout |
2229 |
|
2230 |
\end_inset |
2231 |
|
2232 |
|
2233 |
\end_layout |
2234 |
|
2235 |
\begin_layout Plain Layout |
2236 |
\begin_inset Caption Standard |
2237 |
|
2238 |
\begin_layout Plain Layout |
2239 |
\begin_inset CommandInset label |
2240 |
LatexCommand label |
2241 |
name "fig:model1.modelVessel" |
2242 |
|
2243 |
\end_inset |
2244 |
|
2245 |
First version of the type definition for |
2246 |
\family typewriter |
2247 |
vessel |
2248 |
\family default |
2249 |
. |
2250 |
|
2251 |
\end_layout |
2252 |
|
2253 |
\end_inset |
2254 |
|
2255 |
|
2256 |
\end_layout |
2257 |
|
2258 |
\end_inset |
2259 |
|
2260 |
|
2261 |
\end_layout |
2262 |
|
2263 |
\begin_layout Standard |
2264 |
Our model definition has the following structure for it so far: |
2265 |
\end_layout |
2266 |
|
2267 |
\begin_layout Itemize |
2268 |
|
2269 |
\family typewriter |
2270 |
MODEL |
2271 |
\family default |
2272 |
|
2273 |
\begin_inset Index idx |
2274 |
status collapsed |
2275 |
|
2276 |
\begin_layout Plain Layout |
2277 |
MODEL |
2278 |
\end_layout |
2279 |
|
2280 |
\end_inset |
2281 |
|
2282 |
statement |
2283 |
\end_layout |
2284 |
|
2285 |
\begin_layout Itemize |
2286 |
list of variable we intend to use in the type definition |
2287 |
\end_layout |
2288 |
|
2289 |
\begin_layout Itemize |
2290 |
equations |
2291 |
\end_layout |
2292 |
|
2293 |
\begin_layout Itemize |
2294 |
|
2295 |
\family typewriter |
2296 |
END |
2297 |
\family default |
2298 |
|
2299 |
\begin_inset Index idx |
2300 |
status collapsed |
2301 |
|
2302 |
\begin_layout Plain Layout |
2303 |
END |
2304 |
\end_layout |
2305 |
|
2306 |
\end_inset |
2307 |
|
2308 |
statement |
2309 |
\end_layout |
2310 |
|
2311 |
\begin_layout Standard |
2312 |
While we have put the statements in this order, we could mix up and intermix |
2313 |
the middle two types of statements, even going to the extreme of defining |
2314 |
the variables after we first use them. |
2315 |
The |
2316 |
\family typewriter |
2317 |
MODEL |
2318 |
\family default |
2319 |
and |
2320 |
\family typewriter |
2321 |
END |
2322 |
\family default |
2323 |
statements begin and end the type definition. |
2324 |
\end_layout |
2325 |
|
2326 |
\begin_layout Standard |
2327 |
You should see little that surprises you in the syntax here. |
2328 |
However, you may have noted that we have created a definition that says |
2329 |
absolutely nothing about how to use the variables and equations listed. |
2330 |
There is no solution procedure buried in this type definition. |
2331 |
In ASCEND the idea of solving is separate from saying what we intend to |
2332 |
solve. |
2333 |
Also note that we have not said anything about the values for any of the |
2334 |
variables nor what we intend to calculate and what variables we intend |
2335 |
to treat as fixed input. |
2336 |
\end_layout |
2337 |
|
2338 |
\begin_layout Section |
2339 |
Editing, compiling and browsing an ASCEND model |
2340 |
\end_layout |
2341 |
|
2342 |
\begin_layout Standard |
2343 |
Could we compile an instance of a vessel given this definition? If there |
2344 |
had been some arrays in our definition for which we did not say how many |
2345 |
items were in the arrays, we could not. |
2346 |
However, here we could compile an instance, putting aside storage space |
2347 |
for each of the variables and somehow capturing the equations relating |
2348 |
them. |
2349 |
\end_layout |
2350 |
|
2351 |
\begin_layout Standard |
2352 |
\begin_inset Marginal |
2353 |
status open |
2354 |
|
2355 |
\begin_layout Plain Layout |
2356 |
Do not alter the models subdirectory |
2357 |
\end_layout |
2358 |
|
2359 |
\end_inset |
2360 |
|
2361 |
When we compile new models, we need a place to store them. |
2362 |
One possibility would be to put them into the |
2363 |
\family typewriter |
2364 |
models |
2365 |
\family default |
2366 |
|
2367 |
\begin_inset Index idx |
2368 |
status collapsed |
2369 |
|
2370 |
\begin_layout Plain Layout |
2371 |
models |
2372 |
\end_layout |
2373 |
|
2374 |
\end_inset |
2375 |
|
2376 |
subdirectory of the ASCEND installation |
2377 |
\begin_inset Foot |
2378 |
status collapsed |
2379 |
|
2380 |
\begin_layout Plain Layout |
2381 |
On windows this might be |
2382 |
\family typewriter |
2383 |
c: |
2384 |
\backslash |
2385 |
Program File |
2386 |
\backslash |
2387 |
ASCEND |
2388 |
\backslash |
2389 |
models |
2390 |
\family default |
2391 |
. |
2392 |
On Linux, this might be |
2393 |
\family typewriter |
2394 |
/usr/share/ascend/models |
2395 |
\family default |
2396 |
. |
2397 |
The location can vary depending on how you went about installing ASCEND. |
2398 |
\end_layout |
2399 |
|
2400 |
\end_inset |
2401 |
|
2402 |
. |
2403 |
However, you really should leave the contents of this subdirectory untouched |
2404 |
-- always. |
2405 |
Hopefully the files will be read-only from your user account. |
2406 |
We count on being able to replace the model library totally every time |
2407 |
you install a new version of ASCEND. |
2408 |
Whenever we add new model libraries or corrected versions of previously |
2409 |
existing model libraries, we put them in this subdirectory. |
2410 |
This subdirectory belongs to us (the developers of the system): hands off, |
2411 |
please. |
2412 |
\end_layout |
2413 |
|
2414 |
\begin_layout Standard |
2415 |
\begin_inset Marginal |
2416 |
status open |
2417 |
|
2418 |
\begin_layout Plain Layout |
2419 |
rather put your things into the ascdata |
2420 |
\begin_inset Index idx |
2421 |
status collapsed |
2422 |
|
2423 |
\begin_layout Plain Layout |
2424 |
ascdata |
2425 |
\end_layout |
2426 |
|
2427 |
\end_inset |
2428 |
|
2429 |
subdirectory (you own it) |
2430 |
\end_layout |
2431 |
|
2432 |
\end_inset |
2433 |
|
2434 |
To avoid this problem, ASCEND also creates a subdirectory called |
2435 |
\family typewriter |
2436 |
ascdata |
2437 |
\family default |
2438 |
that it will not touch when you install a new version of ASCEND. |
2439 |
It will look in this subdirectory first when looking for a file to load |
2440 |
when you have not given a full path name for finding that file. |
2441 |
The install process for ASCEND will place |
2442 |
\family typewriter |
2443 |
ascdata |
2444 |
\family default |
2445 |
into your home directory |
2446 |
\begin_inset CommandInset ref |
2447 |
LatexCommand ref |
2448 |
reference "id:#id(pgfId-1007944)" |
2449 |
|
2450 |
\end_inset |
2451 |
|
2452 |
|
2453 |
\begin_inset Foot |
2454 |
status collapsed |
2455 |
|
2456 |
\begin_layout Plain Layout |
2457 |
On Windows, your home directory will normally be the My Documents folder. |
2458 |
On Linux, it will normally be |
2459 |
\family typewriter |
2460 |
/home/ |
2461 |
\emph on |
2462 |
username |
2463 |
\family default |
2464 |
\emph default |
2465 |
. |
2466 |
Note that in both systems, you can set an |
2467 |
\begin_inset Quotes eld |
2468 |
\end_inset |
2469 |
|
2470 |
environment |
2471 |
\begin_inset Quotes erd |
2472 |
\end_inset |
2473 |
|
2474 |
variable to designate your home directory. |
2475 |
\end_layout |
2476 |
|
2477 |
\end_inset |
2478 |
|
2479 |
|
2480 |
\noun off |
2481 |
. |
2482 |
ASCEND tells you where it has placed this subdirectory when you install |
2483 |
it. |
2484 |
However, if you did not note where that was, then you will have to search |
2485 |
for it (using a tool like "FIND file or folder"). |
2486 |
\end_layout |
2487 |
|
2488 |
\begin_layout Standard |
2489 |
It is within the folder |
2490 |
\family typewriter |
2491 |
ascdata |
2492 |
\family default |
2493 |
that you should place any ASCEND models you create. |
2494 |
When running a script (which we shall talk about later), ASCEND first looks |
2495 |
in this subdirectory for files, and then it looks in the models subdirectory. |
2496 |
It stops looking when it finds the first available version of the file. |
2497 |
\end_layout |
2498 |
|
2499 |
\begin_layout Standard |
2500 |
\begin_inset Marginal |
2501 |
status collapsed |
2502 |
|
2503 |
\begin_layout Plain Layout |
2504 |
create a text file containing the model definition |
2505 |
\end_layout |
2506 |
|
2507 |
\end_inset |
2508 |
|
2509 |
Next open an editor |
2510 |
\begin_inset Index idx |
2511 |
status collapsed |
2512 |
|
2513 |
\begin_layout Plain Layout |
2514 |
text editors |
2515 |
\end_layout |
2516 |
|
2517 |
\end_inset |
2518 |
|
2519 |
, such as |
2520 |
\family typewriter |
2521 |
emacs |
2522 |
\family default |
2523 |
|
2524 |
\begin_inset Index idx |
2525 |
status collapsed |
2526 |
|
2527 |
\begin_layout Plain Layout |
2528 |
emacs |
2529 |
\end_layout |
2530 |
|
2531 |
\end_inset |
2532 |
|
2533 |
, |
2534 |
\family typewriter |
2535 |
gedit |
2536 |
\family default |
2537 |
|
2538 |
\begin_inset Index idx |
2539 |
status collapsed |
2540 |
|
2541 |
\begin_layout Plain Layout |
2542 |
gedit |
2543 |
\end_layout |
2544 |
|
2545 |
\end_inset |
2546 |
|
2547 |
, |
2548 |
\family typewriter |
2549 |
vi |
2550 |
\family default |
2551 |
|
2552 |
\begin_inset Index idx |
2553 |
status collapsed |
2554 |
|
2555 |
\begin_layout Plain Layout |
2556 |
vi |
2557 |
\end_layout |
2558 |
|
2559 |
\end_inset |
2560 |
|
2561 |
, |
2562 |
\family typewriter |
2563 |
vim |
2564 |
\family default |
2565 |
|
2566 |
\begin_inset Index idx |
2567 |
status collapsed |
2568 |
|
2569 |
\begin_layout Plain Layout |
2570 |
vim |
2571 |
\end_layout |
2572 |
|
2573 |
\end_inset |
2574 |
|
2575 |
, Notepad |
2576 |
\begin_inset Index idx |
2577 |
status collapsed |
2578 |
|
2579 |
\begin_layout Plain Layout |
2580 |
Notepad |
2581 |
\end_layout |
2582 |
|
2583 |
\end_inset |
2584 |
|
2585 |
or TextPad |
2586 |
\begin_inset Index idx |
2587 |
status collapsed |
2588 |
|
2589 |
\begin_layout Plain Layout |
2590 |
TextPad |
2591 |
\end_layout |
2592 |
|
2593 |
\end_inset |
2594 |
|
2595 |
. |
2596 |
Now type in or, better yet, cut-and-paste the statements in Figure |
2597 |
\begin_inset CommandInset ref |
2598 |
LatexCommand ref |
2599 |
reference "fig:model1.modelVessel" |
2600 |
|
2601 |
\end_inset |
2602 |
|
2603 |
|
2604 |
\noun off |
2605 |
. |
2606 |
Be very careful to match the use of capital and small letters. |
2607 |
Do not worry about blanks between symbols but do not embed blanks within |
2608 |
symbols. |
2609 |
In other words, do not put a blank in the middle of the symbol |
2610 |
\family typewriter |
2611 |
\noun default |
2612 |
side_wall |
2613 |
\family default |
2614 |
\noun off |
2615 |
but do not worry about putting zero or more blanks between |
2616 |
\family typewriter |
2617 |
\noun default |
2618 |
side_wall |
2619 |
\family default |
2620 |
\noun off |
2621 |
and |
2622 |
\family typewriter |
2623 |
\noun default |
2624 |
= |
2625 |
\family default |
2626 |
\noun off |
2627 |
in an equation. |
2628 |
\end_layout |
2629 |
|
2630 |
\begin_layout Standard |
2631 |
When you are finished, be sure to save the file as a text file. |
2632 |
Call it |
2633 |
\family typewriter |
2634 |
vesselPlain.a4c |
2635 |
\family default |
2636 |
. |
2637 |
The " |
2638 |
\family typewriter |
2639 |
.a4c |
2640 |
\family default |
2641 |
" stands for "ASCEND 4 Code". |
2642 |
Many Windows editors will append " |
2643 |
\family typewriter |
2644 |
.txt |
2645 |
\family default |
2646 |
" to the file name. |
2647 |
Remove the |
2648 |
\family typewriter |
2649 |
.txt |
2650 |
\family default |
2651 |
ending off the file name -- do not let Microsoft bully you into thinking |
2652 |
you should not -- and change it to " |
2653 |
\family typewriter |
2654 |
.a4c |
2655 |
\begin_inset Index idx |
2656 |
status collapsed |
2657 |
|
2658 |
\begin_layout Plain Layout |
2659 |
a4c |
2660 |
\end_layout |
2661 |
|
2662 |
\end_inset |
2663 |
|
2664 |
|
2665 |
\family default |
2666 |
". |
2667 |
|
2668 |
\end_layout |
2669 |
|
2670 |
\begin_layout Standard |
2671 |
(This model is also available as |
2672 |
\family typewriter |
2673 |
vesselPlain.a4c |
2674 |
\family default |
2675 |
in the ASCEND models library, but we suggest it would be better for you |
2676 |
to go through the exercise of creating your own version here. |
2677 |
At the least copy the library file to your ASCEND space so you can play |
2678 |
with your own version at this time.) |
2679 |
\end_layout |
2680 |
|
2681 |
\begin_layout Standard |
2682 |
When you are done, you should have a text file called |
2683 |
\family typewriter |
2684 |
vesselPlain.a4c |
2685 |
\family default |
2686 |
stored in your ASCEND/models/vessel subdirectory. |
2687 |
It should contain precisely the statements in Figure |
2688 |
\begin_inset CommandInset ref |
2689 |
LatexCommand ref |
2690 |
reference "fig:model1.modelVessel" |
2691 |
|
2692 |
\end_inset |
2693 |
|
2694 |
|
2695 |
\noun off |
2696 |
with care having been taken to match capital and lower case letters as |
2697 |
shown there. |
2698 |
\end_layout |
2699 |
|
2700 |
\begin_layout Standard |
2701 |
\begin_inset Marginal |
2702 |
status collapsed |
2703 |
|
2704 |
\begin_layout Plain Layout |
2705 |
start the ASCEND system. |
2706 |
Move and resize the windows to make yourself comfortable. |
2707 |
\end_layout |
2708 |
|
2709 |
\end_inset |
2710 |
|
2711 |
Start the ASCEND system by double clicking on the ASCEND icon if you are |
2712 |
on Windows or typing |
2713 |
\family typewriter |
2714 |
ascend |
2715 |
\family default |
2716 |
at the command line if you are using a Linux machine |
2717 |
\begin_inset Foot |
2718 |
status collapsed |
2719 |
|
2720 |
\begin_layout Plain Layout |
2721 |
Depending on the Linux version you have installed, you might find that the |
2722 |
command is |
2723 |
\family typewriter |
2724 |
ascend4 |
2725 |
\family default |
2726 |
or that you have an ASCEND option in your GNOME 'Applications' menu. |
2727 |
\end_layout |
2728 |
|
2729 |
\end_inset |
2730 |
|
2731 |
. |
2732 |
Four windows will appear, three smaller ones and one larger one that will, |
2733 |
if left unattended, disappear by itself in a few seconds. |
2734 |
Move the three smaller ones around on your screen so they do not overlap |
2735 |
or so they overlap very little. |
2736 |
Resize them if you want to. |
2737 |
You might start by putting the one called Script |
2738 |
\begin_inset Index idx |
2739 |
status collapsed |
2740 |
|
2741 |
\begin_layout Plain Layout |
2742 |
Script window |
2743 |
\end_layout |
2744 |
|
2745 |
\end_inset |
2746 |
|
2747 |
in the upper left, the one called Library |
2748 |
\begin_inset Index idx |
2749 |
status collapsed |
2750 |
|
2751 |
\begin_layout Plain Layout |
2752 |
Library window |
2753 |
\end_layout |
2754 |
|
2755 |
\end_inset |
2756 |
|
2757 |
in the upper right and the one called Console |
2758 |
\begin_inset Index idx |
2759 |
status collapsed |
2760 |
|
2761 |
\begin_layout Plain Layout |
2762 |
Console |
2763 |
\end_layout |
2764 |
|
2765 |
\end_inset |
2766 |
|
2767 |
in the lower right. |
2768 |
We shall assume you have placed them in these positions in the following |
2769 |
so, even if that is not your favorite placement, it might be useful to |
2770 |
use it for now. |
2771 |
\end_layout |
2772 |
|
2773 |
\begin_layout Standard |
2774 |
\begin_inset Marginal |
2775 |
status collapsed |
2776 |
|
2777 |
\begin_layout Plain Layout |
2778 |
note that each window by itself looks pretty nonthreatening |
2779 |
\end_layout |
2780 |
|
2781 |
\end_inset |
2782 |
|
2783 |
As you can see, each window by itself looks like a pretty normal window. |
2784 |
Each has buttons across the top under which one will find different tools |
2785 |
to run. |
2786 |
Each also has one to three sub-windows for displaying things. |
2787 |
Each has a Help button that you can push at any time that you want to read |
2788 |
all kinds of detailed things about the window |
2789 |
\begin_inset Foot |
2790 |
status collapsed |
2791 |
|
2792 |
\begin_layout Plain Layout |
2793 |
assuming you have got the help files installed on your system, which you |
2794 |
may not find you have. |
2795 |
\end_layout |
2796 |
|
2797 |
\end_inset |
2798 |
|
2799 |
. |
2800 |
For the moment we will provide you with the "just-in-time" details here |
2801 |
so you do not need to be sidetracked just yet by pushing these Help buttons. |
2802 |
\end_layout |
2803 |
|
2804 |
\begin_layout Standard |
2805 |
\begin_inset Marginal |
2806 |
status collapsed |
2807 |
|
2808 |
\begin_layout Plain Layout |
2809 |
hey, where did that window go? I want it back NOW! |
2810 |
\end_layout |
2811 |
|
2812 |
\end_inset |
2813 |
|
2814 |
If you ever lose a window, open the Script window and under the Tools |
2815 |
\begin_inset Index idx |
2816 |
status collapsed |
2817 |
|
2818 |
\begin_layout Plain Layout |
2819 |
Tools |
2820 |
\end_layout |
2821 |
|
2822 |
\end_inset |
2823 |
|
2824 |
button, select the window you wish to open. |
2825 |
You cannot lose the Script window unless you shut down ASCEND. |
2826 |
For other windows in ASCEND, you can close them and re-open them as required. |
2827 |
Any window that you closed can usually be restored by going back to the |
2828 |
Script window and selected it from the Tools menu there. |
2829 |
\end_layout |
2830 |
|
2831 |
\begin_layout Standard |
2832 |
\begin_inset Marginal |
2833 |
status collapsed |
2834 |
|
2835 |
\begin_layout Plain Layout |
2836 |
How do I quit |
2837 |
\begin_inset Index idx |
2838 |
status collapsed |
2839 |
|
2840 |
\begin_layout Plain Layout |
2841 |
quit ASCEND |
2842 |
\end_layout |
2843 |
|
2844 |
\end_inset |
2845 |
|
2846 |
ASCEND? |
2847 |
\end_layout |
2848 |
|
2849 |
\end_inset |
2850 |
|
2851 |
To exit |
2852 |
\begin_inset Index idx |
2853 |
status collapsed |
2854 |
|
2855 |
\begin_layout Plain Layout |
2856 |
exit ASCEND |
2857 |
\end_layout |
2858 |
|
2859 |
\end_inset |
2860 |
|
2861 |
ASCEND, close the Script window. |
2862 |
You will be asked to confirm that you want to exit ASCEND. |
2863 |
If you have simulations in memory this will stop you from losing your results. |
2864 |
\end_layout |
2865 |
|
2866 |
\begin_layout Standard |
2867 |
\begin_inset Marginal |
2868 |
status collapsed |
2869 |
|
2870 |
\begin_layout Plain Layout |
2871 |
saving |
2872 |
\begin_inset Index idx |
2873 |
status collapsed |
2874 |
|
2875 |
\begin_layout Plain Layout |
2876 |
saving window position |
2877 |
\end_layout |
2878 |
|
2879 |
\end_inset |
2880 |
|
2881 |
window positions |
2882 |
\begin_inset Index idx |
2883 |
status collapsed |
2884 |
|
2885 |
\begin_layout Plain Layout |
2886 |
window position |
2887 |
\end_layout |
2888 |
|
2889 |
\end_inset |
2890 |
|
2891 |
|
2892 |
\end_layout |
2893 |
|
2894 |
\end_inset |
2895 |
|
2896 |
ASCEND will not remember your window locations automatically. |
2897 |
If you like where you have placed the windows for ASCEND on your display, |
2898 |
go to the Script window and select 'Save all appearances |
2899 |
\begin_inset Index idx |
2900 |
status collapsed |
2901 |
|
2902 |
\begin_layout Plain Layout |
2903 |
window locations, save |
2904 |
\end_layout |
2905 |
|
2906 |
\end_inset |
2907 |
|
2908 |
|
2909 |
\begin_inset Index idx |
2910 |
status collapsed |
2911 |
|
2912 |
\begin_layout Plain Layout |
2913 |
appearances, save all |
2914 |
\end_layout |
2915 |
|
2916 |
\end_inset |
2917 |
|
2918 |
' under the View |
2919 |
\begin_inset Index idx |
2920 |
status collapsed |
2921 |
|
2922 |
\begin_layout Plain Layout |
2923 |
View |
2924 |
\end_layout |
2925 |
|
2926 |
\end_inset |
2927 |
|
2928 |
menu. |
2929 |
A similar tool exists for each window for saving only its position. |
2930 |
\end_layout |
2931 |
|
2932 |
\begin_layout Standard |
2933 |
\begin_inset Marginal |
2934 |
status collapsed |
2935 |
|
2936 |
\begin_layout Plain Layout |
2937 |
start by loading and compiling using tools in the Library window |
2938 |
\end_layout |
2939 |
|
2940 |
\end_inset |
2941 |
|
2942 |
We shall start with the Library window in the upper right. |
2943 |
This window provides you with the tools to load and compile files containing |
2944 |
type definitions. |
2945 |
You can also display |
2946 |
\begin_inset Index idx |
2947 |
status collapsed |
2948 |
|
2949 |
\begin_layout Plain Layout |
2950 |
display |
2951 |
\end_layout |
2952 |
|
2953 |
\end_inset |
2954 |
|
2955 |
the code for the different types you have loaded. |
2956 |
\end_layout |
2957 |
|
2958 |
\begin_layout Standard |
2959 |
\begin_inset Marginal |
2960 |
status collapsed |
2961 |
|
2962 |
\begin_layout Plain Layout |
2963 |
use the left mouse button unless we tell you otherwise (however, on you |
2964 |
own explore using the right mouse button in any of the windows) |
2965 |
\end_layout |
2966 |
|
2967 |
\end_inset |
2968 |
|
2969 |
Let's load your file. |
2970 |
Under the File button select the 'Read types from File |
2971 |
\begin_inset Index idx |
2972 |
status collapsed |
2973 |
|
2974 |
\begin_layout Plain Layout |
2975 |
Read Types from File |
2976 |
\end_layout |
2977 |
|
2978 |
\end_inset |
2979 |
|
2980 |
' tool. |
2981 |
You select this tool by clicking on it using the left mouse button - i.e., |
2982 |
the button you should have expected to use. |
2983 |
A window will appear asking you to find the file you want to read into |
2984 |
ASCEND. |
2985 |
Navigate to where you stored |
2986 |
\family typewriter |
2987 |
vesselPlain.a4c |
2988 |
\family default |
2989 |
(in the subdirectory |
2990 |
\family typewriter |
2991 |
ascdata |
2992 |
\family default |
2993 |
) and select that file. |
2994 |
If you have the wrong ending on the file (you left |
2995 |
\family typewriter |
2996 |
.txt |
2997 |
\family default |
2998 |
or you forgot to put |
2999 |
\family typewriter |
3000 |
.a4c |
3001 |
\family default |
3002 |
as the ending), tell the system to list all files and pick the one you |
3003 |
want. |
3004 |
The |
3005 |
\family typewriter |
3006 |
.a4c |
3007 |
\family default |
3008 |
is used by the system to list only the files it thinks you might want to |
3009 |
load, but ASCEND isn't fussy. |
3010 |
It will attempt to load any file you pick. |
3011 |
\end_layout |
3012 |
|
3013 |
\begin_layout Standard |
3014 |
Look in the Console window at the lower right, and, if the file loads without |
3015 |
any errors being listed there, you can skip past the next bit to where |
3016 |
you should start to compile an instance. |
3017 |
The next bit has some useful hints on how to debug your models. |
3018 |
If you want some debugging experience, put a known error into your |
3019 |
\family typewriter |
3020 |
vesselPlain.a4c |
3021 |
\family default |
3022 |
file and see what happens. |
3023 |
This move will give you a reason to read the following section. |
3024 |
\end_layout |
3025 |
|
3026 |
\begin_layout Standard |
3027 |
\begin_inset Marginal |
3028 |
status open |
3029 |
|
3030 |
\begin_layout Plain Layout |
3031 |
Do not ignore the diagnostics |
3032 |
\begin_inset Index idx |
3033 |
status collapsed |
3034 |
|
3035 |
\begin_layout Plain Layout |
3036 |
diagnostics |
3037 |
\end_layout |
3038 |
|
3039 |
\end_inset |
3040 |
|
3041 |
that might appear in the Console window |
3042 |
\end_layout |
3043 |
|
3044 |
\end_inset |
3045 |
|
3046 |
If the Console window in the lower right starts filling with several tens |
3047 |
of lines of diagnostics, look to see if you included the |
3048 |
\family typewriter |
3049 |
REQUIRE |
3050 |
\family default |
3051 |
|
3052 |
\begin_inset Index idx |
3053 |
status collapsed |
3054 |
|
3055 |
\begin_layout Plain Layout |
3056 |
REQUIRE |
3057 |
\end_layout |
3058 |
|
3059 |
\end_inset |
3060 |
|
3061 |
statement at the beginning of your model file. |
3062 |
Without that statement, ASCEND is missing all the definitions for the types |
3063 |
of variables in your model, and it will go wild telling you so |
3064 |
\begin_inset Foot |
3065 |
status collapsed |
3066 |
|
3067 |
\begin_layout Plain Layout |
3068 |
It might also be choking on a Word document because you forgot to save |
3069 |
it as a text file. |
3070 |
\end_layout |
3071 |
|
3072 |
\end_inset |
3073 |
|
3074 |
. |
3075 |
\end_layout |
3076 |
|
3077 |
\begin_layout Standard |
3078 |
While loading the files containing these types, ASCEND will look very closely |
3079 |
at the syntax and will give you all kinds of diagnostic messages in the |
3080 |
Console window (lower right) if you have done something wrong. |
3081 |
It will also at times spew out some warning messages |
3082 |
\begin_inset Index idx |
3083 |
status collapsed |
3084 |
|
3085 |
\begin_layout Plain Layout |
3086 |
warning messages |
3087 |
\end_layout |
3088 |
|
3089 |
\end_inset |
3090 |
|
3091 |
if you have done something thought to be poor modeling style. |
3092 |
You must heed the error messages as the file will not load if there are |
3093 |
any. |
3094 |
ASCEND will tell you if it did not load the file. |
3095 |
|
3096 |
\end_layout |
3097 |
|
3098 |
\begin_layout Standard |
3099 |
You should consider heeding the warnings if you get any. |
3100 |
If you ignore them now, they may come back and haunt you later. |
3101 |
However, there are times when we issue a warning but everything will work, |
3102 |
and you will think we were not too clever. |
3103 |
Our response: better modeling style |
3104 |
\begin_inset Index idx |
3105 |
status collapsed |
3106 |
|
3107 |
\begin_layout Plain Layout |
3108 |
modeling style |
3109 |
\end_layout |
3110 |
|
3111 |
\end_inset |
3112 |
|
3113 |
can eliminate these warnings. |
3114 |
(It's been our system so we get to have the last word.) |
3115 |
\end_layout |
3116 |
|
3117 |
\begin_layout Standard |
3118 |
\begin_inset Marginal |
3119 |
status collapsed |
3120 |
|
3121 |
\begin_layout Plain Layout |
3122 |
how do I jump |
3123 |
\begin_inset Index idx |
3124 |
status collapsed |
3125 |
|
3126 |
\begin_layout Plain Layout |
3127 |
jump to line |
3128 |
\end_layout |
3129 |
|
3130 |
\end_inset |
3131 |
|
3132 |
|
3133 |
\begin_inset Index idx |
3134 |
status collapsed |
3135 |
|
3136 |
\begin_layout Plain Layout |
3137 |
line numbers |
3138 |
\end_layout |
3139 |
|
3140 |
\end_inset |
3141 |
|
3142 |
to line 100 of a file when using some of the standard editors? |
3143 |
\end_layout |
3144 |
|
3145 |
\end_inset |
3146 |
|
3147 |
The error and warning messages will contain a line number in the file where |
3148 |
the error has occurred. |
3149 |
This will be the line number as counted by an editor with the first line |
3150 |
being line 1 in the file. |
3151 |
Editors always provide you with a means to get directly to a line number |
3152 |
in a file. |
3153 |
Find out how to do that or you will not be too happy with debugging a large |
3154 |
file. |
3155 |
\end_layout |
3156 |
|
3157 |
\begin_layout Standard |
3158 |
You will be in the debug mode for a new system so do not expect it to be |
3159 |
totally obvious the first few times you make an error. |
3160 |
We have tried to use language that should be meaningful, but we may have |
3161 |
failed or the error may be pretty subtle and not possible for us to anticipate |
3162 |
how to describe it in your terms. |
3163 |
(Send us a bug report if you have any good ideas on language.) |
3164 |
\end_layout |
3165 |
|
3166 |
\begin_layout Standard |
3167 |
\begin_inset Marginal |
3168 |
status collapsed |
3169 |
|
3170 |
\begin_layout Plain Layout |
3171 |
reloading a file |
3172 |
\begin_inset Index idx |
3173 |
status collapsed |
3174 |
|
3175 |
\begin_layout Plain Layout |
3176 |
reloading a file |
3177 |
\end_layout |
3178 |
|
3179 |
\end_inset |
3180 |
|
3181 |
|
3182 |
\begin_inset Index idx |
3183 |
status collapsed |
3184 |
|
3185 |
\begin_layout Plain Layout |
3186 |
file, reloading |
3187 |
\end_layout |
3188 |
|
3189 |
\end_inset |
3190 |
|
3191 |
overwrites the previous version |
3192 |
\end_layout |
3193 |
|
3194 |
\end_inset |
3195 |
|
3196 |
You can reload any file your have corrected using the Read types from file |
3197 |
tool under the File menu. |
3198 |
It will overwrite the previous version of the file only if the file has |
3199 |
changed since it was last loaded (note that we do not reload those big |
3200 |
files unless you make a change even if you tell us to). |
3201 |
\end_layout |
3202 |
|
3203 |
\begin_layout Standard |
3204 |
\begin_inset Marginal |
3205 |
status collapsed |
3206 |
|
3207 |
\begin_layout Plain Layout |
3208 |
displaying the code |
3209 |
\end_layout |
3210 |
|
3211 |
\end_inset |
3212 |
|
3213 |
You can display the code you have written. |
3214 |
Select the model vessel in the right window of the Library. |
3215 |
Then under the Display |
3216 |
\begin_inset Index idx |
3217 |
status collapsed |
3218 |
|
3219 |
\begin_layout Plain Layout |
3220 |
Display window |
3221 |
\end_layout |
3222 |
|
3223 |
\end_inset |
3224 |
|
3225 |
menu at the top, select the tool Code. |
3226 |
The Display window will open displaying the code for this model. |
3227 |
\end_layout |
3228 |
|
3229 |
\begin_layout Standard |
3230 |
\begin_inset Marginal |
3231 |
status collapsed |
3232 |
|
3233 |
\begin_layout Plain Layout |
3234 |
now compile as " |
3235 |
\family typewriter |
3236 |
v |
3237 |
\family default |
3238 |
" |
3239 |
\end_layout |
3240 |
|
3241 |
\end_inset |
3242 |
|
3243 |
Okay, you have your file loaded without getting any diagnostics. |
3244 |
You are ready to compile |
3245 |
\begin_inset Index idx |
3246 |
status collapsed |
3247 |
|
3248 |
\begin_layout Plain Layout |
3249 |
compile |
3250 |
\end_layout |
3251 |
|
3252 |
\end_inset |
3253 |
|
3254 |
. |
3255 |
In the Library window, look in the left window and select the file |
3256 |
\family typewriter |
3257 |
vesselPlain.a4c |
3258 |
\family default |
3259 |
. |
3260 |
It contains the type definition you wish to compile. |
3261 |
You should see the type vessel appear in the right window. |
3262 |
Select vessel. |
3263 |
Under the Edit button, select Create simulation. |
3264 |
A small window opens and asks you to name the simulation. |
3265 |
Call it |
3266 |
\family typewriter |
3267 |
v |
3268 |
\family default |
3269 |
-- yes, just the letter "v", and select "OK". |
3270 |
Short names for instances often seem to be preferable. |
3271 |
|
3272 |
\end_layout |
3273 |
|
3274 |
\begin_layout Standard |
3275 |
Look again in the Console window for diagnostics. |
3276 |
If everything worked without error, you will see some statistics telling |
3277 |
you how many models, relations and so forth you have created during the |
3278 |
compile step. |
3279 |
\end_layout |
3280 |
|
3281 |
\begin_layout Standard |
3282 |
\begin_inset Marginal |
3283 |
status collapsed |
3284 |
|
3285 |
\begin_layout Plain Layout |
3286 |
and pass the instance |
3287 |
\begin_inset Index idx |
3288 |
status collapsed |
3289 |
|
3290 |
\begin_layout Plain Layout |
3291 |
instance |
3292 |
\end_layout |
3293 |
|
3294 |
\end_inset |
3295 |
|
3296 |
to the Browser |
3297 |
\begin_inset Index idx |
3298 |
status collapsed |
3299 |
|
3300 |
\begin_layout Plain Layout |
3301 |
Browser |
3302 |
\end_layout |
3303 |
|
3304 |
\end_inset |
3305 |
|
3306 |
|
3307 |
\end_layout |
3308 |
|
3309 |
\end_inset |
3310 |
|
3311 |
Select |
3312 |
\family typewriter |
3313 |
v IS A vessel |
3314 |
\family default |
3315 |
in the bottom of the Library window. |
3316 |
Then under the Export |
3317 |
\begin_inset Index idx |
3318 |
status collapsed |
3319 |
|
3320 |
\begin_layout Plain Layout |
3321 |
Export |
3322 |
\end_layout |
3323 |
|
3324 |
\end_inset |
3325 |
|
3326 |
button, select 'Simulation to Browser |
3327 |
\begin_inset Index idx |
3328 |
status collapsed |
3329 |
|
3330 |
\begin_layout Plain Layout |
3331 |
Export Simulation to Browser |
3332 |
\end_layout |
3333 |
|
3334 |
\end_inset |
3335 |
|
3336 |
' to export |
3337 |
\family typewriter |
3338 |
v |
3339 |
\family default |
3340 |
to the Browser tool set. |
3341 |
The Browser window will open and contain |
3342 |
\family typewriter |
3343 |
v |
3344 |
\family default |
3345 |
. |
3346 |
It might be useful to enlarge this window and move it down a bit, placing |
3347 |
it a bit to the right of the center of your screen. |
3348 |
(Remember you can save this positioning and sizing of the Browser window |
3349 |
by going under the View menu and picking 'Save appearance'.) |
3350 |
\end_layout |
3351 |
|
3352 |
\begin_layout Standard |
3353 |
\begin_inset Marginal |
3354 |
status collapsed |
3355 |
|
3356 |
\begin_layout Plain Layout |
3357 |
examine |
3358 |
\family typewriter |
3359 |
v |
3360 |
\family default |
3361 |
by playing with it in the Browser |
3362 |
\end_layout |
3363 |
|
3364 |
\end_inset |
3365 |
|
3366 |
In the left upper window of the Browser, you will find |
3367 |
\family typewriter |
3368 |
v |
3369 |
\family default |
3370 |
to be the current object. |
3371 |
Listed in the right window are all the parts of the current object. |
3372 |
You will see the variables listed here along with an indication of their |
3373 |
type. |
3374 |
For example, you will find |
3375 |
\family typewriter |
3376 |
Cylinder IS A relation |
3377 |
\family default |
3378 |
and |
3379 |
\family typewriter |
3380 |
D IS A distance |
3381 |
\family default |
3382 |
listed, among many others. |
3383 |
|
3384 |
\family typewriter |
3385 |
Cylinder |
3386 |
\family default |
3387 |
is one of the equations you wrote describing the model while |
3388 |
\family typewriter |
3389 |
D |
3390 |
\family default |
3391 |
was the diameter of the vessel. |
3392 |
|
3393 |
\end_layout |
3394 |
|
3395 |
\begin_layout Standard |
3396 |
\begin_inset Marginal |
3397 |
status collapsed |
3398 |
|
3399 |
\begin_layout Plain Layout |
3400 |
included flags |
3401 |
\begin_inset Index idx |
3402 |
status collapsed |
3403 |
|
3404 |
\begin_layout Plain Layout |
3405 |
included flags |
3406 |
\end_layout |
3407 |
|
3408 |
\end_inset |
3409 |
|
3410 |
|
3411 |
\begin_inset Index idx |
3412 |
status collapsed |
3413 |
|
3414 |
\begin_layout Plain Layout |
3415 |
flag, included |
3416 |
\end_layout |
3417 |
|
3418 |
\end_inset |
3419 |
|
3420 |
for relations |
3421 |
\end_layout |
3422 |
|
3423 |
\end_inset |
3424 |
|
3425 |
If you pick any of the parts in the right or bottom windows, it becomes |
3426 |
the current object; its parts then show in the right window. |
3427 |
For example, a relation has a boolean part (a flag that takes the value |
3428 |
|
3429 |
\family typewriter |
3430 |
TRUE |
3431 |
\family default |
3432 |
or |
3433 |
\family typewriter |
3434 |
FALSE |
3435 |
\family default |
3436 |
) indicating whether or not it is to be included when ASCEND solves the |
3437 |
equations you defined for the model. |
3438 |
\end_layout |
3439 |
|
3440 |
\begin_layout Standard |
3441 |
If you wish to display the current value for this flag, pick 'Display Atom |
3442 |
Values |
3443 |
\begin_inset Index idx |
3444 |
status collapsed |
3445 |
|
3446 |
\begin_layout Plain Layout |
3447 |
Display Atom Values |
3448 |
\end_layout |
3449 |
|
3450 |
\end_inset |
3451 |
|
3452 |
' under the View menu. |
3453 |
This tool toggles a switch that causes either the value or the type to |
3454 |
show for a variable, a constant or a relation in the upper right window |
3455 |
of the Browser. |
3456 |
Try toggling it back and forth and looking at different things in the Browser. |
3457 |
\end_layout |
3458 |
|
3459 |
\begin_layout Standard |
3460 |
Pick each of the tools under View and note what happens to the displaying |
3461 |
of things in the Browser. |
3462 |
\end_layout |
3463 |
|
3464 |
\begin_layout Standard |
3465 |
Across the bottom of the Browser window note the buttons you can select |
3466 |
labeled |
3467 |
\family typewriter |
3468 |
RV |
3469 |
\family default |
3470 |
, |
3471 |
\family typewriter |
3472 |
DV |
3473 |
\family default |
3474 |
and so forth. |
3475 |
If you have made the Browser window large enough, you will see to the right |
3476 |
of these buttons the type of objects whose value you want to appear or |
3477 |
not in the lower Browser window as you toggle each button. |
3478 |
Toggle each of these buttons and see if the lower display changes. |
3479 |
If it does not, then this type of part is not in the current object. |
3480 |
\end_layout |
3481 |
|
3482 |
\begin_layout Section |
3483 |
Solving |
3484 |
\begin_inset Index idx |
3485 |
status collapsed |
3486 |
|
3487 |
\begin_layout Plain Layout |
3488 |
Solving |
3489 |
\end_layout |
3490 |
|
3491 |
\end_inset |
3492 |
|
3493 |
an ASCEND instance |
3494 |
\end_layout |
3495 |
|
3496 |
\begin_layout Standard |
3497 |
Well, you have been patient. |
3498 |
While there are lots of interesting tools left to explore in the Browser, |
3499 |
perhaps it is time to try to solve this model. |
3500 |
To solve |
3501 |
\family typewriter |
3502 |
v |
3503 |
\family default |
3504 |
, make it the current object (it alone should be listed in the upper left |
3505 |
window of the Browser). |
3506 |
Then, under the Export |
3507 |
\begin_inset Index idx |
3508 |
status collapsed |
3509 |
|
3510 |
\begin_layout Plain Layout |
3511 |
Export to Solver |
3512 |
\end_layout |
3513 |
|
3514 |
\end_inset |
3515 |
|
3516 |
menu, select 'to Solver'. |
3517 |
The Solver window will open, along with a smaller window labeled Eligible |
3518 |
\begin_inset Index idx |
3519 |
status collapsed |
3520 |
|
3521 |
\begin_layout Plain Layout |
3522 |
window, Eligible |
3523 |
\end_layout |
3524 |
|
3525 |
\end_inset |
3526 |
|
3527 |
|
3528 |
\begin_inset Index idx |
3529 |
status collapsed |
3530 |
|
3531 |
\begin_layout Plain Layout |
3532 |
Eligible window |
3533 |
\end_layout |
3534 |
|
3535 |
\end_inset |
3536 |
|
3537 |
. |
3538 |
Move the Eligible window up a bit so it does not cover any or very little |
3539 |
of the Solver window. |
3540 |
Move the Solver window to the lower left and enlarge it so you can see |
3541 |
all of its contents. |
3542 |
|
3543 |
\end_layout |
3544 |
|
3545 |
\begin_layout Standard |
3546 |
\begin_inset Marginal |
3547 |
status collapsed |
3548 |
|
3549 |
\begin_layout Plain Layout |
3550 |
if ASCEND stops responding |
3551 |
\begin_inset Index idx |
3552 |
status collapsed |
3553 |
|
3554 |
\begin_layout Plain Layout |
3555 |
responding, ASCEND stops |
3556 |
\end_layout |
3557 |
|
3558 |
\end_inset |
3559 |
|
3560 |
, hunt down one of those "nasty" windows with a "yellow lock |
3561 |
\begin_inset Index idx |
3562 |
status collapsed |
3563 |
|
3564 |
\begin_layout Plain Layout |
3565 |
yellow lock |
3566 |
\end_layout |
3567 |
|
3568 |
\end_inset |
3569 |
|
3570 |
" and close it properly |
3571 |
\end_layout |
3572 |
|
3573 |
\end_inset |
3574 |
|
3575 |
This Eligible window is 'modal': if it is open and you do not do something |
3576 |
to make it happy and go away, it will stop you from doing anything else |
3577 |
in the ASCEND system. |
3578 |
Such windows appear with a black lock icon in a yellow field -- we shall |
3579 |
call it a "yellow lock." They demand you attend to them |
3580 |
\emph on |
3581 |
now |
3582 |
\emph default |
3583 |
. |
3584 |
A good solution would be for such a window to stay open and on top of all |
3585 |
the other open windows. |
3586 |
Unfortunately we have not been able under all window managers to stop it |
3587 |
from ducking under another window. |
3588 |
If you ever find ASCEND unwilling to respond, iconify the other windows |
3589 |
to get them out of the way, until you find one of these windows. |
3590 |
On the PC you can go to the icon bar at the bottom of your screen and, |
3591 |
by clicking on the window, bring it to the top. |
3592 |
Then do whatever it takes to make it happy and close properly -- such as |
3593 |
cancel it. |
3594 |
If you are not careful here, for example, this window will hide under the |
3595 |
Solver window before you are through with it. |
3596 |
\end_layout |
3597 |
|
3598 |
\begin_layout Standard |
3599 |
\begin_inset Marginal |
3600 |
status open |
3601 |
|
3602 |
\begin_layout Plain Layout |
3603 |
is our problem well-posed |
3604 |
\begin_inset Index idx |
3605 |
status collapsed |
3606 |
|
3607 |
\begin_layout Plain Layout |
3608 |
well-posed |
3609 |
\end_layout |
3610 |
|
3611 |
\end_inset |
3612 |
|
3613 |
? |
3614 |
\end_layout |
3615 |
|
3616 |
\end_inset |
3617 |
|
3618 |
The Solver window contains the information we need to see to explain why |
3619 |
the Eligible window opened in the first place. |
3620 |
Examine the information the Solver displays. |
3621 |
It tells you that |
3622 |
\family typewriter |
3623 |
v |
3624 |
\family default |
3625 |
has 6 relations defining it and that all are equalities and included. |
3626 |
It has no inequalities. |
3627 |
On the right side we see there are 10 variables and all are 'free |
3628 |
\begin_inset Index idx |
3629 |
status collapsed |
3630 |
|
3631 |
\begin_layout Plain Layout |
3632 |
free variables |
3633 |
\end_layout |
3634 |
|
3635 |
\end_inset |
3636 |
|
3637 |
.' A free variable is one for which you want the system to compute a value. |
3638 |
Hmm, 6 equations in 10 variables. |
3639 |
Something is wrong here. |
3640 |
For a well-posed problem, you want 6 equations in 6 variables (i.e., square |
3641 |
\begin_inset Index idx |
3642 |
status collapsed |
3643 |
|
3644 |
\begin_layout Plain Layout |
3645 |
square |
3646 |
\end_layout |
3647 |
|
3648 |
\end_inset |
3649 |
|
3650 |
). |
3651 |
ASCEND reports that the system is underspecified |
3652 |
\begin_inset Index idx |
3653 |
status collapsed |
3654 |
|
3655 |
\begin_layout Plain Layout |
3656 |
underspecified |
3657 |
\end_layout |
3658 |
|
3659 |
\end_inset |
3660 |
|
3661 |
by 4. |
3662 |
This means you need to pick four of the variables and declare them to be |
3663 |
fixed |
3664 |
\begin_inset Index idx |
3665 |
status collapsed |
3666 |
|
3667 |
\begin_layout Plain Layout |
3668 |
fixed |
3669 |
\end_layout |
3670 |
|
3671 |
\end_inset |
3672 |
|
3673 |
. |
3674 |
You will also have to pick values for these fixed variables before you |
3675 |
can solve for the remaining 6. |
3676 |
For such a small problem as this one, this task is not formidable. |
3677 |
For a model with 50,000 equations and 60,000 variables, one would quit |
3678 |
and go home. |
3679 |
We have exposed a need here. |
3680 |
We certainly would like ASCEND to help us here for this small problem. |
3681 |
But we insist that it help us in major ways to make the 50,000 equation, |
3682 |
60,000 variable problem possible. |
3683 |
\end_layout |
3684 |
|
3685 |
\begin_layout Standard |
3686 |
\begin_inset Marginal |
3687 |
status collapsed |
3688 |
|
3689 |
\begin_layout Plain Layout |
3690 |
picking variables we are going to fix |
3691 |
\end_layout |
3692 |
|
3693 |
\end_inset |
3694 |
|
3695 |
Okay, the small help such as needed here is why the Eligible window opened. |
3696 |
Let's return to it. |
3697 |
It lists all the variables of those not yet fixed that are eligible to |
3698 |
be fixed and still leave us a calculation that has a chance to solve. |
3699 |
The algorithm to find eligible variables does an quick analysis of the |
3700 |
structure of the equations. |
3701 |
The variables it lists are those that can be fixed |
3702 |
\emph on |
3703 |
without |
3704 |
\emph default |
3705 |
the system becoming numerically singular. |
3706 |
So any variables that are not shown |
3707 |
\emph on |
3708 |
cannot possibly |
3709 |
\emph default |
3710 |
help you. |
3711 |
\end_layout |
3712 |
|
3713 |
\begin_layout Standard |
3714 |
So look at the list and decide what you would like to fix for your first |
3715 |
calculation with this model. |
3716 |
Diameter ( |
3717 |
\family typewriter |
3718 |
v.D |
3719 |
\family default |
3720 |
) seems a good choice. |
3721 |
Now you can see why we called the instance just plain old |
3722 |
\family typewriter |
3723 |
v |
3724 |
\family default |
3725 |
. |
3726 |
A longer name would get tiring here. |
3727 |
Anyway, pick |
3728 |
\family typewriter |
3729 |
v.D |
3730 |
\family default |
3731 |
. |
3732 |
Immediately the list reappears with |
3733 |
\family typewriter |
3734 |
v.D |
3735 |
\family default |
3736 |
no longer on it. |
3737 |
ASCEND has just repeated the eligibility analysis, and found that more |
3738 |
variables still need to be fixed. |
3739 |
\end_layout |
3740 |
|
3741 |
\begin_layout Standard |
3742 |
We have three more to pick. |
3743 |
On the list are both vessel height, |
3744 |
\family typewriter |
3745 |
v.H |
3746 |
\family default |
3747 |
, and |
3748 |
\family typewriter |
3749 |
v.H_to_D_ratio |
3750 |
\family default |
3751 |
. |
3752 |
We certainly cannot pick both of these. |
3753 |
One implies the other if we know a value for |
3754 |
\family typewriter |
3755 |
v.D |
3756 |
\family default |
3757 |
. |
3758 |
Pick |
3759 |
\family typewriter |
3760 |
v.H_to_D_ratio |
3761 |
\family default |
3762 |
. |
3763 |
Note that |
3764 |
\family typewriter |
3765 |
v.H |
3766 |
\family default |
3767 |
is no longer eligible. |
3768 |
Good. |
3769 |
We would be worried if it were still there. |
3770 |
\end_layout |
3771 |
|
3772 |
\begin_layout Standard |
3773 |
We see |
3774 |
\family typewriter |
3775 |
v.metal_density |
3776 |
\emph on |
3777 |
. |
3778 |
|
3779 |
\family default |
3780 |
\emph default |
3781 |
Pick it. |
3782 |
Strange. |
3783 |
Metal mass and volume stayed eligible. |
3784 |
Why? If we pick metal mass, wall thickness is implied, and the same is |
3785 |
true if we were to pick metal volume. |
3786 |
However, as it seems much more natural to pick |
3787 |
\family typewriter |
3788 |
wall_thickness |
3789 |
\family default |
3790 |
, make that the last variable you choose. |
3791 |
The Solver window now says this problem is square (i.e., it has 6 equations |
3792 |
in the same number of unknowns). |
3793 |
Table |
3794 |
\begin_inset CommandInset ref |
3795 |
LatexCommand ref |
3796 |
reference "tab:model1.variableFixed" |
3797 |
|
3798 |
\end_inset |
3799 |
|
3800 |
|
3801 |
\noun off |
3802 |
summarizes the four variables we have elected here to fix. |
3803 |
\end_layout |
3804 |
|
3805 |
\begin_layout Standard |
3806 |
\begin_inset Float table |
3807 |
wide false |
3808 |
sideways false |
3809 |
status open |
3810 |
|
3811 |
\begin_layout Plain Layout |
3812 |
\begin_inset Caption Standard |
3813 |
|
3814 |
\begin_layout Plain Layout |
3815 |
\begin_inset CommandInset label |
3816 |
LatexCommand label |
3817 |
name "tab:model1.variableFixed" |
3818 |
|
3819 |
\end_inset |
3820 |
|
3821 |
Variables we have fixed |
3822 |
\begin_inset Index idx |
3823 |
status collapsed |
3824 |
|
3825 |
\begin_layout Plain Layout |
3826 |
fixed variables |
3827 |
\end_layout |
3828 |
|
3829 |
\end_inset |
3830 |
|
3831 |
|
3832 |
\end_layout |
3833 |
|
3834 |
\end_inset |
3835 |
|
3836 |
|
3837 |
\end_layout |
3838 |
|
3839 |
\begin_layout Plain Layout |
3840 |
\begin_inset Tabular |
3841 |
<lyxtabular version="3" rows="5" columns="1"> |
3842 |
<features rotate="0" tabularvalignment="middle"> |
3843 |
<column alignment="center" valignment="top"> |
3844 |
<row> |
3845 |
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none"> |
3846 |
\begin_inset Text |
3847 |
|
3848 |
\begin_layout Plain Layout |
3849 |
variable |
3850 |
\end_layout |
3851 |
|
3852 |
\end_inset |
3853 |
</cell> |
3854 |
</row> |
3855 |
<row> |
3856 |
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
3857 |
\begin_inset Text |
3858 |
|
3859 |
\begin_layout Plain Layout |
3860 |
|
3861 |
\family typewriter |
3862 |
D |
3863 |
\end_layout |
3864 |
|
3865 |
\end_inset |
3866 |
</cell> |
3867 |
</row> |
3868 |
<row> |
3869 |
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
3870 |
\begin_inset Text |
3871 |
|
3872 |
\begin_layout Plain Layout |
3873 |
|
3874 |
\family typewriter |
3875 |
H_to_D_ratio |
3876 |
\end_layout |
3877 |
|
3878 |
\end_inset |
3879 |
</cell> |
3880 |
</row> |
3881 |
<row> |
3882 |
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
3883 |
\begin_inset Text |
3884 |
|
3885 |
\begin_layout Plain Layout |
3886 |
|
3887 |
\family typewriter |
3888 |
meta_density |
3889 |
\end_layout |
3890 |
|
3891 |
\end_inset |
3892 |
</cell> |
3893 |
</row> |
3894 |
<row> |
3895 |
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none"> |
3896 |
\begin_inset Text |
3897 |
|
3898 |
\begin_layout Plain Layout |
3899 |
|
3900 |
\family typewriter |
3901 |
wall_thickness |
3902 |
\end_layout |
3903 |
|
3904 |
\end_inset |
3905 |
</cell> |
3906 |
</row> |
3907 |
</lyxtabular> |
3908 |
|
3909 |
\end_inset |
3910 |
|
3911 |
|
3912 |
\end_layout |
3913 |
|
3914 |
\end_inset |
3915 |
|
3916 |
|
3917 |
\end_layout |
3918 |
|
3919 |
\begin_layout Standard |
3920 |
\begin_inset Marginal |
3921 |
status collapsed |
3922 |
|
3923 |
\begin_layout Plain Layout |
3924 |
ASCEND partitions the problem into smaller problems for solving |
3925 |
\end_layout |
3926 |
|
3927 |
\end_inset |
3928 |
|
3929 |
Toward the bottom right of the |
3930 |
\series bold |
3931 |
Solver |
3932 |
\series default |
3933 |
window, we see there are 6 "blocks |
3934 |
\begin_inset Index idx |
3935 |
status collapsed |
3936 |
|
3937 |
\begin_layout Plain Layout |
3938 |
blocks |
3939 |
\end_layout |
3940 |
|
3941 |
\end_inset |
3942 |
|
3943 |
." What are blocks? ASCEND has examined the equations and, in this case, |
3944 |
has discovered that not all the equations have to be solved simultaneously. |
3945 |
There are 6 blocks of equations which it can solve in sequence. |
3946 |
6 blocks and 6 equations means that ASCEND has found a way to solve the |
3947 |
model by solving 6 individual equations in sequence -- i.e., one at a time. |
3948 |
This is a good thing: it usually means that the solver will have less problems |
3949 |
with locating the overall solution. |
3950 |
\end_layout |
3951 |
|
3952 |
\begin_layout Standard |
3953 |
As well as breaking down the system into blocks, ASCEND has the ability |
3954 |
to rearrange some simple algebraic equations so that unknown variables |
3955 |
can be evaluated directly from the known values, with no need for iterative |
3956 |
numerical methods. |
3957 |
This is only possible if there is just one equation in the block. |
3958 |
In fact, this problem, with the 4 variables we selected to be fixed, can |
3959 |
be solved entirely without iteration. |
3960 |
\end_layout |
3961 |
|
3962 |
\begin_layout Standard |
3963 |
\begin_inset Marginal |
3964 |
status open |
3965 |
|
3966 |
\begin_layout Plain Layout |
3967 |
displaying the incidence matrix |
3968 |
\begin_inset Index idx |
3969 |
status collapsed |
3970 |
|
3971 |
\begin_layout Plain Layout |
3972 |
incidence matrix |
3973 |
\end_layout |
3974 |
|
3975 |
\end_inset |
3976 |
|
3977 |
|
3978 |
\end_layout |
3979 |
|
3980 |
\end_inset |
3981 |
|
3982 |
Can we see what ASCEND has just discovered? It turns out we can (we would |
3983 |
not have asked if we could not). |
3984 |
Under the Display menu on the Solver, select the 'Incidence matrix tool |
3985 |
\begin_inset Index idx |
3986 |
status collapsed |
3987 |
|
3988 |
\begin_layout Plain Layout |
3989 |
incidence matrix tool |
3990 |
\end_layout |
3991 |
|
3992 |
\end_inset |
3993 |
|
3994 |
'. |
3995 |
A window pops open showing us the incidence of variables in the equations |
3996 |
and display them in the order that ASCEND has found to solve them, also |
3997 |
known as a sparsity matrix |
3998 |
\begin_inset Index idx |
3999 |
status collapsed |
4000 |
|
4001 |
\begin_layout Plain Layout |
4002 |
sparsity matrix |
4003 |
\end_layout |
4004 |
|
4005 |
\end_inset |
4006 |
|
4007 |
or sparsity pattern |
4008 |
\begin_inset Index idx |
4009 |
status collapsed |
4010 |
|
4011 |
\begin_layout Plain Layout |
4012 |
sparsity pattern |
4013 |
\end_layout |
4014 |
|
4015 |
\end_inset |
4016 |
|
4017 |
. |
4018 |
The dark squares are incidences under the variables for which we are solving; |
4019 |
the lighter looking 'X' symbols to the right side are incidences for the |
4020 |
fixed (known) variables. |
4021 |
Click on the incidence in the upper left corner. |
4022 |
ASCEND immediately identifies it for us as the |
4023 |
\family typewriter |
4024 |
end_area |
4025 |
\family default |
4026 |
. |
4027 |
It identifies the equation as the one we labeled |
4028 |
\family typewriter |
4029 |
FlatEnds |
4030 |
\family default |
4031 |
. |
4032 |
We can go back to our model and find the equation ASCEND will solve first. |
4033 |
The other variable in this equation is in the set we fixed; pick it and |
4034 |
discover it is |
4035 |
\family typewriter |
4036 |
D |
4037 |
\family default |
4038 |
, the vessel diameter. |
4039 |
Of course we can compute the area of the ends given the diameter. |
4040 |
The |
4041 |
\emph on |
4042 |
end_area |
4043 |
\emph default |
4044 |
is |
4045 |
\begin_inset Formula $\pi D^{2}/4$ |
4046 |
\end_inset |
4047 |
|
4048 |
. |
4049 |
\end_layout |
4050 |
|
4051 |
\begin_layout Standard |
4052 |
Play with the other incidences here. |
4053 |
See what the other equations are and the order ASCEND will use to solve |
4054 |
them. |
4055 |
\end_layout |
4056 |
|
4057 |
\begin_layout Standard |
4058 |
Okay, we return to our task of solving. |
4059 |
We need next to supply values for the variables we have selected to be |
4060 |
fixed. |
4061 |
Again, the approach we are going to take is acceptable for this small problem, |
4062 |
but we would not want to have to do what we are about to do for a large |
4063 |
problem. |
4064 |
Fortunately, we really have thought about these issues and have some nice |
4065 |
approaches that work even for extremely large problem -- like 100,000 equations. |
4066 |
\end_layout |
4067 |
|
4068 |
\begin_layout Standard |
4069 |
\begin_inset Marginal |
4070 |
status collapsed |
4071 |
|
4072 |
\begin_layout Plain Layout |
4073 |
which variables are currently fixed for this problem? |
4074 |
\end_layout |
4075 |
|
4076 |
\end_inset |
4077 |
|
4078 |
Let's see. |
4079 |
Do you remember the variables we fixed? What if you do not? Well, we go |
4080 |
back to the Browser. |
4081 |
Be sure |
4082 |
\family typewriter |
4083 |
v |
4084 |
\family default |
4085 |
remains the current object (it alone is in the upper left window). |
4086 |
Under the Find menu select 'by Type |
4087 |
\begin_inset Index idx |
4088 |
status collapsed |
4089 |
|
4090 |
\begin_layout Plain Layout |
4091 |
Find by Type |
4092 |
\end_layout |
4093 |
|
4094 |
\end_inset |
4095 |
|
4096 |
.' A small window opens with default information in it saying it will find |
4097 |
for us all objects contained in the current object |
4098 |
\family typewriter |
4099 |
v |
4100 |
\family default |
4101 |
of type |
4102 |
\family typewriter |
4103 |
solver_var |
4104 |
\family default |
4105 |
whose |
4106 |
\family typewriter |
4107 |
fixed |
4108 |
\family default |
4109 |
flags are set to |
4110 |
\family typewriter |
4111 |
TRUE |
4112 |
\family default |
4113 |
. |
4114 |
These are precisely the attributes for the variables we have fixed. |
4115 |
Select OK and a list of the four variables we fixed earlier appears. |
4116 |
\end_layout |
4117 |
|
4118 |
\begin_layout Standard |
4119 |
\begin_inset Marginal |
4120 |
status collapsed |
4121 |
|
4122 |
\begin_layout Plain Layout |
4123 |
specifying values for the fixed variables - this approach is useful for |
4124 |
small problems |
4125 |
\end_layout |
4126 |
|
4127 |
\end_inset |
4128 |
|
4129 |
For each variable on this list, we should supply a value. |
4130 |
Select |
4131 |
\family typewriter |
4132 |
D |
4133 |
\family default |
4134 |
in the lower window of the Browser using the right (the right, not the |
4135 |
left -- make |
4136 |
\family typewriter |
4137 |
v |
4138 |
\family default |
4139 |
the current object and do it again) mouse button. |
4140 |
A window opens in which we input a value for |
4141 |
\family typewriter |
4142 |
D |
4143 |
\family default |
4144 |
. |
4145 |
Put in the value 4 in the left window and ft in the right. |
4146 |
Continue by putting in the values for the variables as listed in Table |
4147 |
|
4148 |
\begin_inset CommandInset ref |
4149 |
LatexCommand ref |
4150 |
reference "tab:model1.valuesFixedVars" |
4151 |
|
4152 |
\end_inset |
4153 |
|
4154 |
|
4155 |
\noun off |
4156 |
. |
4157 |
These values immediately appear in the Browser window as you enter them. |
4158 |
If you did not fully appreciate the proper handling of dimension and units |
4159 |
before, you just got a taste of its advantages. |
4160 |
|
4161 |
\noun default |
4162 |
You |
4163 |
\noun off |
4164 |
did not have to worry about specifying these things in consistent preselected |
4165 |
units |
4166 |
\noun default |
4167 |
-- ASCEND did this for you. |
4168 |
\end_layout |
4169 |
|
4170 |
\begin_layout Standard |
4171 |
\begin_inset Float table |
4172 |
wide false |
4173 |
sideways false |
4174 |
status open |
4175 |
|
4176 |
\begin_layout Plain Layout |
4177 |
\begin_inset Caption Standard |
4178 |
|
4179 |
\begin_layout Plain Layout |
4180 |
\begin_inset CommandInset label |
4181 |
LatexCommand label |
4182 |
name "tab:model1.valuesFixedVars" |
4183 |
|
4184 |
\end_inset |
4185 |
|
4186 |
Values to use for fixed variables |
4187 |
\end_layout |
4188 |
|
4189 |
\end_inset |
4190 |
|
4191 |
|
4192 |
\end_layout |
4193 |
|
4194 |
\begin_layout Plain Layout |
4195 |
\begin_inset Tabular |
4196 |
<lyxtabular version="3" rows="5" columns="3"> |
4197 |
<features rotate="0" tabularvalignment="middle"> |
4198 |
<column alignment="center" valignment="top"> |
4199 |
<column alignment="center" valignment="top"> |
4200 |
<column alignment="center" valignment="top"> |
4201 |
<row> |
4202 |
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> |
4203 |
\begin_inset Text |
4204 |
|
4205 |
\begin_layout Plain Layout |
4206 |
variable |
4207 |
\end_layout |
4208 |
|
4209 |
\end_inset |
4210 |
</cell> |
4211 |
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> |
4212 |
\begin_inset Text |
4213 |
|
4214 |
\begin_layout Plain Layout |
4215 |
value |
4216 |
\end_layout |
4217 |
|
4218 |
\end_inset |
4219 |
</cell> |
4220 |
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none"> |
4221 |
\begin_inset Text |
4222 |
|
4223 |
\begin_layout Plain Layout |
4224 |
units |
4225 |
\end_layout |
4226 |
|
4227 |
\end_inset |
4228 |
</cell> |
4229 |
</row> |
4230 |
<row> |
4231 |
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
4232 |
\begin_inset Text |
4233 |
|
4234 |
\begin_layout Plain Layout |
4235 |
|
4236 |
\family typewriter |
4237 |
D |
4238 |
\end_layout |
4239 |
|
4240 |
\end_inset |
4241 |
</cell> |
4242 |
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
4243 |
\begin_inset Text |
4244 |
|
4245 |
\begin_layout Plain Layout |
4246 |
4 |
4247 |
\end_layout |
4248 |
|
4249 |
\end_inset |
4250 |
</cell> |
4251 |
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
4252 |
\begin_inset Text |
4253 |
|
4254 |
\begin_layout Plain Layout |
4255 |
|
4256 |
\family typewriter |
4257 |
ft |
4258 |
\end_layout |
4259 |
|
4260 |
\end_inset |
4261 |
</cell> |
4262 |
</row> |
4263 |
<row> |
4264 |
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
4265 |
\begin_inset Text |
4266 |
|
4267 |
\begin_layout Plain Layout |
4268 |
|
4269 |
\family typewriter |
4270 |
H_to_D_ratio |
4271 |
\end_layout |
4272 |
|
4273 |
\end_inset |
4274 |
</cell> |
4275 |
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
4276 |
\begin_inset Text |
4277 |
|
4278 |
\begin_layout Plain Layout |
4279 |
3 |
4280 |
\end_layout |
4281 |
|
4282 |
\end_inset |
4283 |
</cell> |
4284 |
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
4285 |
\begin_inset Text |
4286 |
|
4287 |
\begin_layout Plain Layout |
4288 |
|
4289 |
\end_layout |
4290 |
|
4291 |
\end_inset |
4292 |
</cell> |
4293 |
</row> |
4294 |
<row> |
4295 |
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
4296 |
\begin_inset Text |
4297 |
|
4298 |
\begin_layout Plain Layout |
4299 |
|
4300 |
\family typewriter |
4301 |
meta_density |
4302 |
\end_layout |
4303 |
|
4304 |
\end_inset |
4305 |
</cell> |
4306 |
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
4307 |
\begin_inset Text |
4308 |
|
4309 |
\begin_layout Plain Layout |
4310 |
5000 |
4311 |
\end_layout |
4312 |
|
4313 |
\end_inset |
4314 |
</cell> |
4315 |
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
4316 |
\begin_inset Text |
4317 |
|
4318 |
\begin_layout Plain Layout |
4319 |
|
4320 |
\family typewriter |
4321 |
kg/m^3 |
4322 |
\end_layout |
4323 |
|
4324 |
\end_inset |
4325 |
</cell> |
4326 |
</row> |
4327 |
<row> |
4328 |
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> |
4329 |
\begin_inset Text |
4330 |
|
4331 |
\begin_layout Plain Layout |
4332 |
|
4333 |
\family typewriter |
4334 |
wall_thickness |
4335 |
\end_layout |
4336 |
|
4337 |
\end_inset |
4338 |
</cell> |
4339 |
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> |
4340 |
\begin_inset Text |
4341 |
|
4342 |
\begin_layout Plain Layout |
4343 |
5 |
4344 |
\end_layout |
4345 |
|
4346 |
\end_inset |
4347 |
</cell> |
4348 |
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none"> |
4349 |
\begin_inset Text |
4350 |
|
4351 |
\begin_layout Plain Layout |
4352 |
|
4353 |
\family typewriter |
4354 |
mm |
4355 |
\end_layout |
4356 |
|
4357 |
\end_inset |
4358 |
</cell> |
4359 |
</row> |
4360 |
</lyxtabular> |
4361 |
|
4362 |
\end_inset |
4363 |
|
4364 |
|
4365 |
\end_layout |
4366 |
|
4367 |
\end_inset |
4368 |
|
4369 |
|
4370 |
\end_layout |
4371 |
|
4372 |
\begin_layout Standard |
4373 |
You can now solve this model. |
4374 |
Go the Solver window and, under the Execute menu, select Solve. |
4375 |
You will get a message telling you the model solved. |
4376 |
Dismiss that message and return to the Browser window to examine the results. |
4377 |
You should see the following results: |
4378 |
\end_layout |
4379 |
|
4380 |
\begin_layout LyX-Code |
4381 |
\begin_inset ERT |
4382 |
status open |
4383 |
|
4384 |
\begin_layout Plain Layout |
4385 |
|
4386 |
|
4387 |
\backslash |
4388 |
begin{ascend} |
4389 |
\end_layout |
4390 |
|
4391 |
\begin_layout Plain Layout |
4392 |
|
4393 |
D = 1.21922 meter |
4394 |
\end_layout |
4395 |
|
4396 |
\begin_layout Plain Layout |
4397 |
|
4398 |
H = 3.65765 meter |
4399 |
\end_layout |
4400 |
|
4401 |
\begin_layout Plain Layout |
4402 |
|
4403 |
H_to_D_ratio = 3 |
4404 |
\end_layout |
4405 |
|
4406 |
\begin_layout Plain Layout |
4407 |
|
4408 |
end_area = 1.16748 meter^2 |
4409 |
\end_layout |
4410 |
|
4411 |
\begin_layout Plain Layout |
4412 |
|
4413 |
metal_density = 5000 kilogram/meter^3 |
4414 |
\end_layout |
4415 |
|
4416 |
\begin_layout Plain Layout |
4417 |
|
4418 |
metal_mass = 408.62 kilogram |
4419 |
\end_layout |
4420 |
|
4421 |
\begin_layout Plain Layout |
4422 |
|
4423 |
side_area = 14.0098 meter^2 |
4424 |
\end_layout |
4425 |
|
4426 |
\begin_layout Plain Layout |
4427 |
|
4428 |
vessel_vol = 4.27025 meter^3 |
4429 |
\end_layout |
4430 |
|
4431 |
\begin_layout Plain Layout |
4432 |
|
4433 |
wall_thickness = 0.005 meter |
4434 |
\end_layout |
4435 |
|
4436 |
\begin_layout Plain Layout |
4437 |
|
4438 |
wall_vol = 0.0817239 meter^3 |
4439 |
\end_layout |
4440 |
|
4441 |
\begin_layout Plain Layout |
4442 |
|
4443 |
|
4444 |
\backslash |
4445 |
end{ascend} |
4446 |
\end_layout |
4447 |
|
4448 |
\end_inset |
4449 |
|
4450 |
|
4451 |
\end_layout |
4452 |
|
4453 |
\begin_layout LyX-Code |
4454 |
|
4455 |
\end_layout |
4456 |
|
4457 |
\begin_layout Standard |
4458 |
\begin_inset Note Note |
4459 |
status collapsed |
4460 |
|
4461 |
\begin_layout Plain Layout |
4462 |
Some of this stuff appears to have changed in the PDF.... |
4463 |
\end_layout |
4464 |
|
4465 |
\end_inset |
4466 |
|
4467 |
|
4468 |
\end_layout |
4469 |
|
4470 |
\begin_layout Standard |
4471 |
\begin_inset Marginal |
4472 |
status collapsed |
4473 |
|
4474 |
\begin_layout Plain Layout |
4475 |
alter the units used for displaying values |
4476 |
\end_layout |
4477 |
|
4478 |
\end_inset |
4479 |
|
4480 |
You may wish to alter the units used to display these results. |
4481 |
For example, you enter the diameter |
4482 |
\emph on |
4483 |
D |
4484 |
\emph default |
4485 |
in ft. |
4486 |
You may wish to reassure yourself the |
4487 |
\family typewriter |
4488 |
1.21922 meter |
4489 |
\family default |
4490 |
is 4 ft. |
4491 |
Go to the Script window and under the Tools menu select |
4492 |
\emph on |
4493 |
' |
4494 |
\emph default |
4495 |
Measuring units'. |
4496 |
The |
4497 |
\series bold |
4498 |
Units |
4499 |
\series default |
4500 |
window |
4501 |
\begin_inset Index idx |
4502 |
status collapsed |
4503 |
|
4504 |
\begin_layout Plain Layout |
4505 |
Units window |
4506 |
\end_layout |
4507 |
|
4508 |
\end_inset |
4509 |
|
4510 |
|
4511 |
\begin_inset Index idx |
4512 |
status collapsed |
4513 |
|
4514 |
\begin_layout Plain Layout |
4515 |
window, Units |
4516 |
\end_layout |
4517 |
|
4518 |
\end_inset |
4519 |
|
4520 |
will open. |
4521 |
Enlarge it appropriately and then place it to the top and far right of |
4522 |
your display. |
4523 |
\end_layout |
4524 |
|
4525 |
\begin_layout Standard |
4526 |
There are two ways you can reset the units for displaying length. |
4527 |
\end_layout |
4528 |
|
4529 |
\begin_layout Enumerate |
4530 |
Length is a basic dimension in ASCEND so under the |
4531 |
\emph on |
4532 |
Display |
4533 |
\emph default |
4534 |
button select Length. |
4535 |
A side window will open with all the alternate units supported in ASCEND |
4536 |
for length. |
4537 |
Select ft. |
4538 |
\end_layout |
4539 |
|
4540 |
\begin_layout Enumerate |
4541 |
Or, in the lower part of the Units window is a frame labeled 'Set units'. |
4542 |
Clear and then type |
4543 |
\family typewriter |
4544 |
ft |
4545 |
\family default |
4546 |
then hit Enter. |
4547 |
\end_layout |
4548 |
|
4549 |
\begin_layout Standard |
4550 |
In either way, the units for all length variables will switch to ft. |
4551 |
Look at the values in the Browser window. |
4552 |
\end_layout |
4553 |
|
4554 |
\begin_layout Standard |
4555 |
The left upper window of the Units window contains many variable types that |
4556 |
have composite dimensions. |
4557 |
For example, you will find volume there. |
4558 |
Pick it and the right window fills with all the alternative units in which |
4559 |
you can express volume. |
4560 |
\end_layout |
4561 |
|
4562 |
\begin_layout Standard |
4563 |
Play with changing the units for displaying the various variables in the |
4564 |
vessel instance v. |
4565 |
|
4566 |
\end_layout |
4567 |
|
4568 |
\begin_layout Standard |
4569 |
One point - the left window displaying types having composite dimensions |
4570 |
will display only one type for each composite dimension. |
4571 |
If the atom types you have loaded were to include volume_difference as |
4572 |
well as volume, then only one of the two types, volume or volume_difference, |
4573 |
will be listed here. |
4574 |
Changing the units to express either changes the units for both. |
4575 |
\end_layout |
4576 |
|
4577 |
\begin_layout Standard |
4578 |
\begin_inset Marginal |
4579 |
status collapsed |
4580 |
|
4581 |
\begin_layout Plain Layout |
4582 |
returning to a consistent set of units |
4583 |
\end_layout |
4584 |
|
4585 |
\end_inset |
4586 |
|
4587 |
When you are done, you may wish to return to a consistent set, such as SI |
4588 |
\begin_inset Index idx |
4589 |
status collapsed |
4590 |
|
4591 |
\begin_layout Plain Layout |
4592 |
SI |
4593 |
\end_layout |
4594 |
|
4595 |
\end_inset |
4596 |
|
4597 |
. |
4598 |
Under the Display button are different sets; pick |
4599 |
\emph on |
4600 |
SI (MKS) set |
4601 |
\emph default |
4602 |
. |
4603 |
\end_layout |
4604 |
|
4605 |
\begin_layout Standard |
4606 |
\begin_inset Marginal |
4607 |
status collapsed |
4608 |
|
4609 |
\begin_layout Plain Layout |
4610 |
now we can solve the model in other ways |
4611 |
\end_layout |
4612 |
|
4613 |
\end_inset |
4614 |
|
4615 |
We can now resolve our vessel instance in any number of different ways. |
4616 |
For example we can ask what the diameter would be if we had a volume of |
4617 |
|
4618 |
\emph on |
4619 |
250 ft3 |
4620 |
\emph default |
4621 |
. |
4622 |
To accomplish this calculation, we need first to make |
4623 |
\emph on |
4624 |
vessel_volume |
4625 |
\emph default |
4626 |
a variable whose value we wish to fix. |
4627 |
When we do this the model will be overspecified. |
4628 |
ASCEND will indicate this problem to us and offer us a list of variables |
4629 |
- including the vessel diameter |
4630 |
\emph on |
4631 |
D |
4632 |
\emph default |
4633 |
, one of which we will have to "unfix |
4634 |
\begin_inset Index idx |
4635 |
status collapsed |
4636 |
|
4637 |
\begin_layout Plain Layout |
4638 |
unfix |
4639 |
\end_layout |
4640 |
|
4641 |
\end_inset |
4642 |
|
4643 |
." Finally we need to alter the value of |
4644 |
\emph on |
4645 |
vessel_volume |
4646 |
\emph default |
4647 |
to the desired value and solve. |
4648 |
Explicit instructions to accomplish these steps are as follows. |
4649 |
\end_layout |
4650 |
|
4651 |
\begin_layout Itemize |
4652 |
In the |
4653 |
\series bold |
4654 |
Browser |
4655 |
\series default |
4656 |
window, make |
4657 |
\emph on |
4658 |
vessel_volume |
4659 |
\emph default |
4660 |
the current object (select it using the left mouse button). |
4661 |
The right window of the |
4662 |
\series bold |
4663 |
Browser |
4664 |
\series default |
4665 |
display the parts of the |
4666 |
\emph on |
4667 |
vessel_volume |
4668 |
\emph default |
4669 |
, among them is the fixed flag with a value of |
4670 |
\emph on |
4671 |
FALSE |
4672 |
\emph default |
4673 |
. |
4674 |
|
4675 |
\end_layout |
4676 |
|
4677 |
\begin_layout Itemize |
4678 |
(If you do not see the value for fixed but rather its type as a boolean, |
4679 |
under the |
4680 |
\emph on |
4681 |
View |
4682 |
\emph default |
4683 |
button at the top, select |
4684 |
\emph on |
4685 |
Display Atom Values. |
4686 |
\emph default |
4687 |
) |
4688 |
\end_layout |
4689 |
|
4690 |
\begin_layout Itemize |
4691 |
Pick fixed with the right mouse button, and, in the small window that opens, |
4692 |
delete the value |
4693 |
\emph on |
4694 |
FALSE |
4695 |
\emph default |
4696 |
, enter the value |
4697 |
\emph on |
4698 |
TRUE |
4699 |
\emph default |
4700 |
and select |
4701 |
\emph on |
4702 |
OK |
4703 |
\emph default |
4704 |
. |
4705 |
\end_layout |
4706 |
|
4707 |
\begin_layout Itemize |
4708 |
Now make v the current object by picking it in the left window of the |
4709 |
\series bold |
4710 |
Browser |
4711 |
\series default |
4712 |
. |
4713 |
\end_layout |
4714 |
|
4715 |
\begin_layout Itemize |
4716 |
Export v to the Solver again by selecting to Solver under the Export button. |
4717 |
A window entitled Overspecified |
4718 |
\begin_inset Index idx |
4719 |
status collapsed |
4720 |
|
4721 |
\begin_layout Plain Layout |
4722 |
Overspecified |
4723 |
\end_layout |
4724 |
|
4725 |
\end_inset |
4726 |
|
4727 |
will appear listing the variables v.D, v.H_to_D_ratio and v.vessel_volume. |
4728 |
Pick v.D and hit the OK button; ASCEND will reset its fixed flag to FALSE. |
4729 |
\end_layout |
4730 |
|
4731 |
\begin_layout Itemize |
4732 |
Finally, return to the |
4733 |
\series bold |
4734 |
Browser |
4735 |
\series default |
4736 |
window and select |
4737 |
\emph on |
4738 |
vessel_volume |
4739 |
\emph default |
4740 |
with the right mouse button. |
4741 |
In the small window that appears type |
4742 |
\emph on |
4743 |
250 |
4744 |
\emph default |
4745 |
in the left window, |
4746 |
\emph on |
4747 |
ft^3 |
4748 |
\emph default |
4749 |
in the right, and hit the |
4750 |
\emph on |
4751 |
OK |
4752 |
\emph default |
4753 |
button. |
4754 |
\end_layout |
4755 |
|
4756 |
\begin_layout Itemize |
4757 |
Under the |
4758 |
\emph on |
4759 |
Execute |
4760 |
\emph default |
4761 |
button in the |
4762 |
\series bold |
4763 |
Solver |
4764 |
\series default |
4765 |
window, select |
4766 |
\emph on |
4767 |
Solve |
4768 |
\emph default |
4769 |
. |
4770 |
\end_layout |
4771 |
|
4772 |
\begin_layout Standard |
4773 |
Note the |
4774 |
\series bold |
4775 |
Solver |
4776 |
\series default |
4777 |
reports only 4 blocks for 6 equations. |
4778 |
This time it has to solve some equations simultaneously. |
4779 |
In the |
4780 |
\series bold |
4781 |
Solver |
4782 |
\series default |
4783 |
window, under the |
4784 |
\emph on |
4785 |
Display |
4786 |
\emph default |
4787 |
button, select the |
4788 |
\emph on |
4789 |
Incidence matrix |
4790 |
\emph default |
4791 |
tool. |
4792 |
You will see that the first three equations must be solved together as |
4793 |
a single block of equations. |
4794 |
\end_layout |
4795 |
|
4796 |
\begin_layout Standard |
4797 |
\begin_inset Marginal |
4798 |
status collapsed |
4799 |
|
4800 |
\begin_layout Plain Layout |
4801 |
clearing all the fixed flags |
4802 |
\end_layout |
4803 |
|
4804 |
\end_inset |
4805 |
|
4806 |
For a more complicated model you may wish to start over on the process of |
4807 |
selecting which variables are fixed. |
4808 |
You can set the fixed flags for all the variables in a problem to FALSE |
4809 |
all at once -- without knowing which are currently set to TRUE. |
4810 |
In the Browser window, under the Edit button, select the Run method tool. |
4811 |
A window will open that displays a list of default methods that are automatical |
4812 |
ly attached to every model in ASCEND. |
4813 |
One is called ClearAll. |
4814 |
Pick it and hit OK. |
4815 |
All the fixed flags for the entire model will now be reset to FALSE. |
4816 |
Can you think of a way to check if this is true? (Do you remember how to |
4817 |
check which variables are currently fixed? Repeat that check and you should |
4818 |
find no variables are on the list.) |
4819 |
\end_layout |
4820 |
|
4821 |
\begin_layout Standard |
4822 |
You might now want to play by changing what you calculate and fix. |
4823 |
\end_layout |
4824 |
|
4825 |
\begin_layout Section |
4826 |
Discussion |
4827 |
\end_layout |
4828 |
|
4829 |
\begin_layout Standard |
4830 |
You have just completed the creation and solving of a very small model in |
4831 |
ASCEND. |
4832 |
In doing so, you have been exposed to some interesting issues. |
4833 |
How can we separate the concept of the model from how we intend to solve |
4834 |
it? How do we make a model to be well-posed -- i.e., a model involving n |
4835 |
equations in n unknowns -- so we can solve it? How should one handle the |
4836 |
units for the variables in a modeling system? What we have shown you here |
4837 |
is for a small model. |
4838 |
We still need to show you how one can make a large model well-posed, for |
4839 |
example. |
4840 |
You will start to understand how one can do this in the next chapter. |
4841 |
\end_layout |
4842 |
|
4843 |
\begin_layout Standard |
4844 |
The next chapter is crucial for you to understand if you want to begin to |
4845 |
understand how we approach good modeling practice. |
4846 |
Please do continue with it. |
4847 |
As it uses the vessel model, it would, of course, be best to continue with |
4848 |
that chapter now. |
4849 |
\end_layout |
4850 |
|
4851 |
\end_body |
4852 |
\end_document |