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-revision 828 by johnpye,
Tue Aug 22 02:24:05 2006 UTC
+revision 1384 by jpye,
Fri Apr  6 16:15:11 2007 UTC
 Line 1
- #LyX 1.4.1 created this file. For more info see http://www.lyx.org/
+ #LyX 1.4.3 created this file. For more info see http://www.lyx.org/
  \lyxformat 245
  \begin_document
  \begin_header
 Line 34
  \begin_body
  \begin_layout Chapter
- Syntax and semantics
+ Syntax reference
  \begin_inset LatexCommand \label{cha:ASCENDSyntax}
  \end_inset
 Line 128 
 The syntax for a computer language is of
  \end_layout
  \begin_deeper
- \begin_layout Section
+ \begin_layout Chapter
  Preliminaries
  \end_layout
 Line 238 
 The ASCEND IV parser is very picky and p
   them learn how to avoid errors.
  \end_layout
- \begin_layout Subsection
+ \begin_layout Section
  Punctuation
  \begin_inset LatexCommand \index{punctuation}
 Line 247 
 Punctuation
  \end_layout
+ \end_deeper
  \begin_layout Standard
  This section covers both the punctuation that must be understood to read
   this document and the punctuation of ASCEND code.
  \end_layout
- \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
  keywords
 Line 285 
 Tips: Special notes and hints are someti
  \labelwidthstring 00000.00000.00000.000
  \bar under
- *3*
- \begin_inset LatexCommand \index{*3*}
- \end_inset
- :
- \bar default
-  This indicates that what follows is specific to ASCEND IIIc and may disappear
-  in a future version of ASCEND IV.
-  Generally ASCEND IV will provide some equivalent functionality at 1/10th
-  of the ASCEND III price.
- \end_layout
- \begin_layout List
- \labelwidthstring 00000.00000.00000.000
- \bar under
- *4*
- \bar default
- \begin_inset LatexCommand \index{*4*}
- \end_inset
-  This indicates that what follows is specific to ASCEND IV and may not be
-  available in ASCEND IIIc.
-  Generally ASCEND III may provide some very klugey equivalent functionality,
-  often at a very high price in terms of increased compilation time or debugging
-  difficulty.
- \end_layout
- \begin_layout List
- \labelwidthstring 00000.00000.00000.000
- \bar under
- *4+*
- \bar default
- \begin_inset LatexCommand \index{*4+*}
- \end_inset
-  ASCEND IV functionality that is not fully implemented at the time of this
-  writing.
-  The precise syntax of the final implementation may vary slightly from what
-  is presented here.
-  A revision of this document will be made at the time of implementation.
- \end_layout
- \begin_layout List
- \labelwidthstring 00000.00000.00000.000
- \bar under
  LHS
  \begin_inset LatexCommand \index{LHS}
-Line 427 
 Groupings:
+Line 374 
 Groupings:
  �\InsetSpace ~
  �
  \bar default
-  In documentation optional fields
+  In documentation
+ \series bold
+ optional fields
+ \series default
  \begin_inset LatexCommand \index{optional fields}
  \end_inset
-Line 437 
 Groupings:
+Line 388 
 Groupings:
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family typewriter
  (*\InsetSpace ~
  *)
+ \family default
  \begin_inset LatexCommand \index{(* *)}
  \end_inset
   Comment.
-  *3* Anything inside these is a comment.
+  Anything inside these is a comment.
-  Comments DO NOT nest in ASCEND IIIc.
+  Comments can nest
-  Comments may extend over many lines.
-  *4* Comments DO nest
  \begin_inset LatexCommand \index{nest}
  \end_inset
-  in ASCEND IV.
+  in ASCEND and span several lines.
  \end_layout
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family typewriter
  (\InsetSpace ~
  )
+ \family default
  \begin_inset LatexCommand \index{( )}
  \end_inset
-Line 490 
 tip: The compiler can simplify relation
+Line 447 
 tip: The compiler can simplify relation
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family typewriter
  {\InsetSpace ~
  }
+ \family default
  \begin_inset LatexCommand \index{{ }}
  \end_inset
-Line 511 
 tip: The compiler can simplify relation
+Line 472 
 tip: The compiler can simplify relation
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family typewriter
  [\InsetSpace ~
  ]
+ \family default
  \begin_inset LatexCommand \index{[ ]}
  \end_inset
-Line 532 
 tip: The compiler can simplify relation
+Line 497 
 tip: The compiler can simplify relation
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family typewriter
  .
+ \family default
  \begin_inset LatexCommand \index{.}
  \end_inset
-Line 551 
 tip: The compiler can simplify relation
+Line 520 
 tip: The compiler can simplify relation
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family typewriter
  ..
+ \family default
  \begin_inset LatexCommand \index{..}
  \end_inset
-Line 572 
 tip: The compiler can simplify relation
+Line 545 
 tip: The compiler can simplify relation
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family typewriter
  :
+ \family default
  \begin_inset LatexCommand \index{:}
  \end_inset
-Line 589 
 tip: The compiler can simplify relation
+Line 566 
 tip: The compiler can simplify relation
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family typewriter
  ::
+ \family default
  \begin_inset LatexCommand \index{::}
  \end_inset
-Line 612 
 tip: The compiler can simplify relation
+Line 593 
 tip: The compiler can simplify relation
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family typewriter
  ;
+ \family default
  \begin_inset LatexCommand \index{;}
  \end_inset
-Line 627 
 tip: The compiler can simplify relation
+Line 612 
 tip: The compiler can simplify relation
  \end_layout
  \begin_deeper
- \begin_layout Subsection
+ \begin_layout Section
  Basic Elements
  \begin_inset LatexCommand \index{basic elements}
-Line 659 
 value
+Line 644 
 value
  \end_inset
-  TRUE
+ \family sans
+ TRUE
+ \family default
  \begin_inset LatexCommand \index{TRUE}
  \end_inset
-  or FALSE
+  or
+ \family sans
+ FALSE
+ \family default
  \begin_inset LatexCommand \index{FALSE}
  \end_inset
  .
-  Can't get much simpler, eh? In the language definition TRUE and FALSE do
+  Can't get much simpler, eh? In the language definition
-  not map to 1 and 0 or any other type of numeric value.
+ \family sans
+ TRUE
+ \family default
+  and
+ \family sans
+ FALSE
+ \family default
+  do not map to 1 and 0 or any other type of numeric value.
   (In the implementation, of course, they do.)
  \end_layout
 Line 704 
 value
   A signed whole number up to the maximum that can be represented by the
   computer on which one is running ASCEND.
-  MAX_INTEGER
+ \family sans
+ MAX_INTEGER
+ \family default
  \begin_inset LatexCommand \index{MAX\_INTEGER}
  \end_inset
-Line 756 
 value
+Line 760 
 value
   has an optional negative sign followed by a string of digits and at most
   one decimal point.
-  The exponent is the letter e or E followed by an integer.
+  The exponent is the letter
+ \family typewriter
+ e
+ \family default
+  or
+ \family typewriter
+ E
+ \family default
+  followed by an integer.
   The number must not exceed the largest the computer is able to handle.
   There can be no blank characters in a real.
-  MAX_REAL
+ \family sans
+ MAX_REAL
+ \family default
  \begin_inset LatexCommand \index{MAX\_REAL}
  \end_inset
-Line 806 
 while the following are not:
+Line 822 
 while the following are not:
  \begin_layout LyX-Code
  \align block
 .
-(*contains a blank within it*)
+   (*contains a blank within it*)
  \end_layout
  \begin_layout LyX-Code
-Line 814 
 while the following are not:
+Line 830 
 while the following are not:
 .3e2.0 (*exponent has a decimal in it*)
  \end_layout
- \begin_layout List
+ \begin_layout LyX-Code
- \labelwidthstring 00000.00000.00000.000
- +1.3 (* illegal unary + sign.
+ \family typewriter
+ +1.3    (* illegal unary + sign.
   x = +1.3 not allowed*)
  \end_layout
-Line 846 
 We store all real values as double preci
+Line 863 
 We store all real values as double preci
  \end_inset
-  numbers in the MKS
+  numbers in the metre-kilogram-second (MKS)
  \begin_inset LatexCommand \index{MKS}
  \end_inset
-Line 871 
 Dimensionality
+Line 888 
 Dimensionality
  :
  \bar default
   Real values have dimensionality such as length/time for velocity.
-  Dimensionality is to be distinguished from the units such as ft/s.
+ \series bold
+ Dimensionality
+ \series default
+  is to be distinguished from the
+ \series bold
+ units
+ \series default
+  such as ft/s.
   ASCEND takes care of mapping between units
  \begin_inset LatexCommand \index{units}
-Line 907 
 L
+Line 932 
 L
  \end_inset
- ; meter, m
+ ; metre, m
  \end_layout
  \begin_layout List
-Line 1053 
 ality.
+Line 1078 
 ality.
  \begin_layout Standard
  Dimensions may be any combination of these symbols along with rounded parenthese
- s, (), and the operators *, ^ and /.
+ s, (), and the operators *,
-  Examples include M/T or M*L^2/T^2/TMP {this latter means (M*(L^2)/(T^2))/TMP}.
+ \family typewriter
-  The second operand for the to the power operator, ^, must be an integer
+ ^
-  value (e.g., -2 or 3) because fractional powers of dimensional numbers are
+ \family default
-  physically undefined.
+  and
+ \family typewriter
+ /
+ \family default
+ .
+  Examples include
+ \family typewriter
+ M/T
+ \family default
+  or
+ \family typewriter
+ M*L^2/T^2/TMP
+ \family default
+  {this latter means
+ \family typewriter
+ (M*(L^2)/(T^2))/TMP
+ \family default
+ }.
+  The second operand for the to-the-power-of operator,
+ \family typewriter
+ ^
+ \family default
+ , must be an integer value (e.g., -2 or 3) because fractional powers of dimensiona
+ l numbers are physically undefined
+ \begin_inset Note Note
+ status open
+ \begin_layout Standard
+ although we do seem them occasionally...
+ \end_layout
+ \end_inset
+ .
  \end_layout
  \begin_layout Standard
  If the dimensionality for a real value is undefined, then ASCEND gives it
-  a wild card dimensionality
+  a wildcard dimensionality
  \begin_inset LatexCommand \index{wild card dimensionality}
  \end_inset
-Line 1070 
 If the dimensionality for a real value i
+Line 1128 
 If the dimensionality for a real value i
  .
   If ASCEND can later deduce its dimensionality from its use in a model definitio
  n it will do so.
-  For example consider the real variable a, suppose a has wild card dimensionalit
+  For example consider the real variable
- y, b has dimensionality of L/T.
+ \family typewriter
+ a
+ \family default
+ , suppose
+ \family typewriter
+ a
+ \family default
+  has wildcard dimensionality,
+ \family typewriter
+ b
+ \family default
+  has dimensionality of
+ \family typewriter
+ L/T
+ \family default
+ .
   Then the statement:
  \end_layout
-Line 1095 
 equation.
+Line 1168 
 equation.
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
  \InsetSpace ~
-  a + b = 3 {ft/s};
+ \family typewriter
+ a + b = 3 {ft/s};
  \end_layout
  \begin_deeper
  \begin_layout Standard
- requires that a have the same dimensionality as the other two terms, namely,
+ requires that
-  L/T.
+ \family typewriter
-  ASCEND will assign this dimensionality to a.
+ a
+ \family default
+  have the same dimensionality as the other two terms, namely,
+ \family typewriter
+ L/T
+ \family default
+ .
+  ASCEND will assign this dimensionality to
+ \family typewriter
+ a
+ \family default
+ .
   The user will be warned of dimensionally inconsistent equations.
  \end_layout
-Line 1120 
 expression
+Line 1206 
 expression
  \end_inset
   may be composed of any combination of unit names defined by the system
-  and any numerical constants combined with times (*), divide(/) and to the
+  and any numerical constants combined with times (
-  power (^) operators.
+ \family typewriter
-  The RHS of ^ must be an integer.
+ *
-  Parentheses can be used to group subexpressions EXCEPT a divide operator
+ \family default
-  may not be followed by a grouped subexpression.
+ ), divide(
+ \family typewriter
+ /
+ \family default
+ ) and to the power (
+ \family typewriter
+ ^
+ \family default
+ ) operators.
+  The RHS of
+ \family typewriter
+ ^
+ \family default
+  must be an integer.
+  Parentheses can be used to group subexpressions with the exception that
+  a divide operator may
+ \emph on
+ not
+ \emph default
+  be followed by a grouped subexpression.
  \end_layout
  \begin_deeper
  \begin_layout Standard
- So, {kg/m/s} is fine, but {kg/(m*s)} is not.
+ So,
+ \family typewriter
+ {kg/m/s}
+ \family default
+  is fine, but
+ \family typewriter
+ {kg/(m*s)}
+ \family default
+  is not.
   Although the two expressions are mathematically equivalent, it makes the
   system programming and output formatting easier to code and faster to execute
   if we disallow expressions of the latter sort.
  \end_layout
  \begin_layout Standard
- The units understood by the system are defined in the
+ The units understood by the system are defined in the first part of this
- \begin_inset Quotes eld
+  manual.
- \end_inset
- howTo
- \begin_inset LatexCommand \cite{key-1}
- \end_inset
- \begin_inset Quotes erd
- \end_inset
-  book available on the ASCEND web site.
   Note that several units defined are really values of interesting constants
   in SI, e.g.
-  R :== 1{GAS_C} yields the correct value of the thermodynamic gas constant.
+ \family typewriter
+ R :== 1{GAS_C}
+ \family default
+  yields the correct value of the thermodynamic gas constant.
   Users can define additional units.
  \end_layout
-Line 1169 
 Units
+Line 1274 
 Units
  \end_inset
-  A Unit expression unit expression must be enclosed in curly braces {}.
+  A Unit expression unit expression must be enclosed in curly braces
+ \family typewriter
+ {}
+ \family default
+ .
   When a real number is used in a mathematical expression in ASCEND, it must
   have a set of units expressed with it.
   If it does not, ASCEND assumes the number is dimensionless, which may not
   be the intent of the modeler.
   An example is shown in the dimensionally consistent equation above where
-  the number 3 has the units {ft/s} associated with it.
+  the number 3 has the units
+ \family typewriter
+ {ft/s}
+ \family default
+  associated with it.
  \end_layout
-Line 1313 
 values
+Line 1426 
 values
  \end_inset
-  Set values are lists of elements, all of type integer_constant or all of
+  Set values are lists of elements, all of type
-  type symbol_constant, enclosed between square brackets [].
+ \family sans
+ integer_constant
+ \family default
+  or all of type
+ \family sans
+ symbol_constant
+ \family default
+ , enclosed between square brackets
+ \family typewriter
+ []
+ \family default
+ .
   The following are examples of sets:
  \end_layout
-Line 1367 
 Section\InsetSpace ~
+Line 1491 
 Section\InsetSpace ~
  \begin_deeper
  \begin_layout Standard
- The value range 1..5 is an allowable shorthand for the integers 1, 2, 3, 4
+ The value range
-  and 5 while the value range 2..n_stages (where n_stages must be of type integer_c
+ \family typewriter
- onstant) means all integers from 2 to n_stages.
+..5
-  If n_stages is less than 2, then the third set is empty.
+ \family default
-  The repeated occurrence of 1 in the fourth set is ignored.
+  is an allowable shorthand for the integers 1, 2, 3, 4 and 5 while the value
+  range
+ \family typewriter
+..n_stages
+ \family default
+  (where
+ \family typewriter
+ n_stages
+ \family default
+  must be of type
+ \family sans
+ integer_constant
+ \family default
+ ) means all integers from 2 to
+ \family typewriter
+ n_stages
+ \family default
+ .
+  If
+ \family typewriter
+ n_stages
+ \family default
+  is less than 2, then the third set is empty.
+  The repeated occurrence of
+ \family typewriter
+ \family default
+  in the fourth set is ignored.
   The fifth set is the empty set
  \begin_inset LatexCommand \index{empty set}
-Line 1394 
 We use the term set in an almost pure ma
+Line 1545 
 We use the term set in an almost pure ma
  \end_inset
-  (CARD
+  (
+ \family sans
+ CARD
+ \family default
  \begin_inset LatexCommand \index{CARD}
  \end_inset
- (set)).
+ \family typewriter
+ (set)
+ \family default
+ ).
   Repeated elements used in defining a set are ignored.
   The elements of sets cannot themselves be sets in ASCEND; i.e., there can
   be no sets of set.
-Line 1457 
 column[areas][processes]
+Line 1616 
 column[areas][processes]
  \begin_layout Standard
  where components, areas and processes are sets.
-  For example components could be the set of symbols ['ethylene', 'propylene'],
+  For example components could be the set of symbols
-  areas the set of symbols ['feed_prep', 'prod_purification'] while processes
+ \family typewriter
-  could be the set ['alcohol_manuf', 'poly_propropylene_manuf'].
+ ['ethylene', 'propylene']
-  Note that the third example (column) is a list of lists (the way that ASCEND
+ \family default
-  permits a multiply subscripted array).
+ , areas the set of symbols
+ \family typewriter
+ ['feed_prep', 'prod_purification']
+ \family default
+  while processes could be the set
+ \family typewriter
+ ['alcohol_manuf', 'poly_propropylene_manuf']
+ \family default
+ .
+  Note that the third example (
+ \family typewriter
+ column
+ \family default
+ ) is a list of lists (the way that ASCEND permits a multiply subscripted
+  array).
  \end_layout
-Line 1482 
 column['feed_prep'][alcohol_manuf']
+Line 1655 
 column['feed_prep'][alcohol_manuf']
  \end_layout
  \begin_layout Standard
- provided that n_stages is 1 or larger.
+ provided that
+ \family typewriter
+ n_stages
+ \family default
+  is 1 or larger.
  \end_layout
-Line 1525 
 jagged
+Line 1702 
 jagged
  \end_inset
-  (* 4 *) Arrays can be sparse
+  Arrays can be sparse
  \begin_inset LatexCommand \index{sparse}
  \end_inset
-Line 1594 
 flow[2][7], flow[2][3], flow[2][5]
+Line 1771 
 flow[2][7], flow[2][3], flow[2][5]
  flow[3][4], flow[3][6]
  \end_layout
- \begin_layout Standard
- Sparse arrays of models and variables are new to ASCEND IV.
- \end_layout
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
-Line 1610 
 instances
+Line 1783 
 instances
  \begin_deeper
  \begin_layout Standard
  Each array is itself an object.
-  That is, when you write "a[1..2] IS_A real;" three objects get created: a[1],
+  That is, when you write
-  a[2], and a.
+ \family typewriter
-  a is an array instance which has parts named [1] and [2] that are real
+ a[1..2] IS_A real
-  instances.
+ \family default
+ , three objects get created:
+ \family typewriter
+ a[1]
+ \family default
+ ,
+ \family typewriter
+ a[2]
+ \family default
+ , and
+ \family typewriter
+ a
+ \family default
+ .
+  The object
+ \family typewriter
+ a
+ \family default
+  is an array instance which has parts named
+ \family typewriter
+ [1]
+ \family default
+  and
+ \family typewriter
+ [2]
+ \family default
+  that are real instances.
   When a parameterized model requires an array, you pass it the single item
-  a, not the elements a[1..2].
+ \family typewriter
+ a
+ \family default
+ , not the elements
+ \family typewriter
+ a[1..2]
+ \family default
+ .
  \end_layout
  \end_deeper
-Line 1849 
 lists
+Line 2056 
 lists
  \end_layout
  \begin_deeper
- \begin_layout Subsection
+ \begin_layout Section
  Basic Concepts
  \end_layout
-Line 1926 
 types
+Line 2133 
 types
   It is possible to create an instance that does not have a corresponding
   type definition in the library.
-  The type of such an instance is said to be implicit.
+  The type of such an instance is said to be
-  (Some people use the word anonymous
+ \series bold
+ implicit
+ \series default
+ \begin_inset Foot
+ status collapsed
+ \begin_layout Standard
+  (Some people use the word
+ \emph on
+ anonymous
+ \emph default
  \begin_inset LatexCommand \index{type, anonymous}
  \end_inset
-Line 1939 
 types
+Line 2158 
 types
  .
   However, no computable type is anonymous and the implicit type of an instance
-  is theoretically computable).
+  is theoretically computable)
+ \end_layout
+ \end_inset
+ .
   The simplest example of an implicit type is the type of an instance compiled
-  from the built-in definition integer_constant.
+  from the built-in definition
+ \family sans
+ integer_constant
+ \family default
+ .
   For example:
  \end_layout
-Line 1959 
 j:== 3;
+Line 2187 
 j:== 3;
  \end_layout
  \begin_layout Standard
- Instances i and j, though of the same formal type, are implicit type incompatibl
+ Instances
- e because they have been assigned distinct values.
+ \family typewriter
+ i
+ \family default
+  and
+ \family typewriter
+ j
+ \family default
+ , though of the same formal type, are implicit type incompatible because
+  they have been assigned distinct values.
  \end_layout
  \begin_layout Standard
-Line 2000 
 Ambiguity is warned about loudly because
+Line 2236 
 Ambiguity is warned about loudly because
  \begin_layout Standard
  Assume a type, stream, and a refinement of stream, heat_stream, which adds
-  the new variable H.
+  the new variable
+ \family typewriter
+ H
+ \family default
+ .
   Now, if we write:
  \end_layout
-Line 2026 
 END mixer;
+Line 2266 
 END mixer;
  \begin_layout Standard
  We see the parser can find the definition of H in the type heat_stream,
-  so output.H is well defined.
+  so
-  The author of the mixer model may intend to refine input[1] and input[2]
+ \family typewriter
+ output.H
+ \family default
+  is well defined.
+  The author of the mixer model may intend to refine
+ \family typewriter
+ input[1]
+ \family default
+  and
+ \family typewriter
+ input[2]
+ \family default
   to be objects of different types, say steam_stream and electric_stream,
-  where each defines an H suitable for use in the equation.
+  where each defines an
-  The parser cannot read the authors mind, so it warns that input[1].H and
+ \family typewriter
-  input[2].H are ambiguous in the mixer definition.
+ H
+ \family default
+  suitable for use in the equation.
+  The parser cannot read the authors mind, so it warns that
+ \family typewriter
+ input[1].H
+ \family default
+  and
+ \family typewriter
+ input[2].H
+ \family default
+  are ambiguous in the mixer definition.
   The mixer model is not highly reusable except by the author, but sometimes
   reusability is not a high priority objective.
   The mixer definition is allowed, but it may cause problems in instantiation
-Line 2109 
 Phase 3 compiles as many logical arithme
+Line 2371 
 Phase 3 compiles as many logical arithme
  \end_layout
  \begin_layout Standard
- Phase 4 compiles as many conditional programming statements (WHENs) as possible.
+ Phase 4 compiles as many conditional programming statements (
-  Some WHEN relations may be impossible to compile because the discrete variables
+ \family sans
- , models, or relations they depend on do not exist.
+ WHEN
+ \family default
+ s) as possible.
+  Some
+ \family sans
+ WHEN
+ \family default
+  relations may be impossible to compile because the discrete variables,
+  models, or relations they depend on do not exist.
   This is determined in a single pass.
  \end_layout
  \begin_layout Standard
  Phase 5 executes the variable defaulting statements made in the declarative
-  section of each model IF AND ONLY IF there are no pending statements from
+  section of each model
-  phases 1-4 anywhere in the simulation.
+ \emph on
+ if and only if
+ \emph default
+  there are no pending statements from phases 1-4 anywhere in the simulation.
  \end_layout
  \end_deeper
-Line 2155 
 Structure building or modifying statemen
+Line 2428 
 Structure building or modifying statemen
   or merge.
  \end_layout
- \begin_layout Section
+ \begin_layout Chapter
  Data Type Declarations
  \begin_inset LatexCommand \index{data type declarations}
-Line 2171 
 In the spectrum of OO languages, ASCEND
+Line 2444 
 In the spectrum of OO languages, ASCEND
  \end_inset
  , though it is rather more a hybrid.
-  We have atom and model definitions, called types, and the compiled objects
+  We have atom and model definitions, called
-  themselves, called instances.
+ \series bold
+ types
+ \series default
+ , and the compiled objects themselves, called
+ \series bold
+ instances
+ \series default
+ .
   ASCEND instances have a record of what type they were constructed from.
  \end_layout
-Line 2192 
 qualifiers
+Line 2472 
 qualifiers
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  UNIVERSAL
+ \family default
  \begin_inset LatexCommand \index{UNIVERSAL}
  \end_inset
-  Universal is an optional modifier of all ATOM, CONSTANT.
+  Universal is an optional modifier of all
-  and MODEL definitions.
+ \family sans
-  If UNIVERSAL precedes the definition, then ALL instances of that type will
+ ATOM
-  actually refer to the first instance of the type that is created.
+ \family default
+ ,
+ \family sans
+ CONSTANT
+ \family default
+  and
+ \family sans
+ MODEL
+ \family default
+  definitions.
+  If
+ \family sans
+ UNIVERSAL
+ \family default
+  precedes the definition, then
+ \emph on
+ all
+ \emph default
+  instances of that type will actually refer to the first instance of the
+  type that is created.
   This saves memory and ensures global consistency of data.
  \end_layout
-Line 2241 
 Tip:\InsetSpace ~
+Line 2544 
 Tip:\InsetSpace ~
  Do\InsetSpace ~
  not\InsetSpace ~
  use\InsetSpace ~
- UNIVERSAL\InsetSpace ~
+ \family sans
+ UNIVERSAL
+ \family default
+ \InsetSpace ~
  variables\InsetSpace ~
  in\InsetSpace ~
  relations.
-Line 2249 
 relations.
+Line 2556 
 relations.
  \begin_deeper
  \begin_layout Standard
- It is important to note that, because variables must store information about
+ It is important to note that, because
-  which relations they occur in, it is a very bad idea to use UNIVERSAL typed
+ \emph on
-  variables in relations.
+ variables
+ \emph default
+  must store information about which relations they occur in, it is a very
+  bad idea to use
+ \family sans
+ UNIVERSAL
+ \family default
+  typed variables in relations.
   The construction and maintenance of the relation list becomes very expensive
   for universal variables.
-  UNIVERSAL constants are fine to use, though, because there are no relation
-  links for constants.
+ \family sans
+ UNIVERSAL
+ \family default
+ \emph on
+ constants
+ \emph default
+  are fine to use, though, because there are no relation links for constants.
  \end_layout
- \begin_layout Subsection
+ \begin_layout Section
  Models
  \end_layout
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  MODEL
+ \family default
  \begin_inset LatexCommand \index{MODEL}
  \end_inset
-Line 2367 
 Models
+Line 2692 
 Models
  \end_inset
-  (* 4 *) Parameterizing models makes them easier to understand and faster
+  Parameterizing models makes them easier to understand and faster for the
-  for the system to compile.
+  system to compile.
   The syntax for a parameterized model vaguely resembles a function call
   in imperative languages, but it is NOT.
   When constructing a reusable model, all the constants that determine the
-Line 2457 
 END flowsheet;
+Line 2782 
 END flowsheet;
  \begin_layout Standard
  In this example, the column model takes the first argument, ntrays, by reference.
-  That is, ct.ntrays is an alias for the flowsheet instance tower4size.
+  That is,
-  tower4size must be compiled and assigned a value before we will attempt
+ \family typewriter
-  to compile the column model instance ct.
+  ct.ntrays
-  The second argument is taken by value, [c5,c6], and assigned to components,
+ \family default
-  a column part that was declared with IS_A in the parameter list.
+  is an alias for the flowsheet instance
-  There is only one name for this set, ct.components.
+ \family typewriter
-  Note that in the flowsheet model there is no part that is a set of symbol_const
+ tower4size
- ant.
+ \family default
+ .
+ \family typewriter
+ tower4size
+ \family default
+  must be compiled and assigned a value before we will attempt to compile
+  the column model instance
+ \family typewriter
+ ct
+ \family default
+ .
+  The second argument is taken by value,
+ \family typewriter
+ [c5,c6]
+ \family default
+ , and assigned to components, a column part that was declared with
+ \family sans
+ IS_A
+ \family default
+  in the parameter list.
+  There is only one name for this set,
+ \family typewriter
+ ct.components
+ \family default
+ .
+  Note that in the
+ \family typewriter
+ flowsheet
+ \family default
+  model there is no part that is a set of
+ \family sans
+ symbol_constant
+ \family default
+ .
  \end_layout
-Line 2482 
 The use of parameters in ASCEND modeling
+Line 2841 
 The use of parameters in ASCEND modeling
   which are not issues in the very earliest phase of developing novel models.
  \end_layout
- \begin_layout Subsection
+ \begin_layout Section
  Sets
  \begin_inset LatexCommand \index{sets}
-Line 2504 
 Arrays in ASCEND, as already discussed i
+Line 2863 
 Arrays in ASCEND, as already discussed i
  , are defined over sets.
   A set is simply an instance with a set value.
-  The elements of sets are NOT instances or sets.
+  The elements of sets are
+ \emph on
+ not
+ \emph default
+  instances or sets.
  \end_layout
  \end_deeper
-Line 2535 
 my_symbol_set IS_A set OF symbol_constan
+Line 2898 
 my_symbol_set IS_A set OF symbol_constan
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family typewriter
  :==
+ \family default
  \begin_inset LatexCommand \index{:==}
  \end_inset
-Line 2563 
 The RHS of such an assignment must be ei
+Line 2930 
 The RHS of such an assignment must be ei
  Set\InsetSpace ~
  Operations
  \bar default
-  UNION
+ \family sans
+ UNION
+ \family default
  \begin_inset LatexCommand \index{UNION}
  \end_inset
+ \family typewriter
  [setlist]
  \end_layout
-Line 2576 
 Operations
+Line 2949 
 Operations
  A function taken over a list of sets.
   The result is the set that includes all the members of all the sets in
   the list.
-  Note that the result of the UNION operation is an unordered set and the
+  Note that the result of the
-  argument order to the union function does not matter.
+ \family sans
+ UNION
+ \family default
+  operation is an unordered set and the argument order to the union function
+  does not matter.
   The syntax is:
  \end_layout
-Line 2589 
 A function taken over a list of sets.
+Line 2966 
 A function taken over a list of sets.
  \end_inset
-  UNION[list_of_sets]
+ \family typewriter
+ UNION[list_of_sets]
  \end_layout
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
- A+B\InsetSpace ~
+ \family typewriter
+ A+B
+ \family default
+ \InsetSpace ~
  is\InsetSpace ~
  shorthand\InsetSpace ~
- for UNION[A,B]
+ for
+ \family typewriter
+ UNION[A,B]
  \end_layout
  \begin_deeper
-Line 2614 
 B := [2, 4, 6, 8];
+Line 2999 
 B := [2, 4, 6, 8];
  \end_layout
  \begin_layout Standard
- Then UNION[A, B] is equal to the set [1, 2, 3, 4, 5, 6, 8, 9] which equals
+ Then
-  [1..6, 8, 9] which equals [[1..9] - [7]].
+ \family typewriter
+ UNION[A, B]
+ \family default
+  is equal to the set
+ \family typewriter
+ [1, 2, 3, 4, 5, 6, 8, 9]
+ \family default
+  which equals
+ \family typewriter
+ [1..6, 8, 9]
+ \family default
+  which equals
+ \family typewriter
+ [[1..9] - [7]]
+ \family default
+ .
  \end_layout
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  INTERSECTION
+ \family default
  \begin_inset LatexCommand \index{INTERSECTION}
  \end_inset
-Line 2638 
 INTERSECTION
+Line 3042 
 INTERSECTION
  \end_inset
-  Equivalent to INTERSECTION[list_of_sets].
+  Equivalent to
+ \family sans
+ INTERSECTION
+ \family typewriter
+ [list_of_sets]
+ \family default
+ .
  \end_layout
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
- A*B\InsetSpace ~
+ \family typewriter
+ A*B
+ \family default
+ \InsetSpace ~
  is\InsetSpace ~
  shorthand\InsetSpace ~
  for\InsetSpace ~
- INTERSECTION[A,B]
+ I
+ \family typewriter
+ NTERSECTION[A,B]
  \end_layout
  \begin_deeper
  \begin_layout Standard
- For the sets A and B defined just above, INTERSECTION[A, B] is the set [2].
+ For the sets A and B defined just above,
-  The * shorthand for intersection is NOT recommended for use except in libraries
+ \family typewriter
-  no one will look at.
+ INTERSECTION[A, B]
+ \family default
+  is the set
+ \family typewriter
+ [2]
+ \family default
+ .
+  The
+ \family typewriter
+ *
+ \family default
+  shorthand for intersection is
+ \emph on
+ not
+ \emph default
+  recommended for use except in libraries no one will look at.
  \end_layout
  \end_deeper
-Line 2672 
 difference
+Line 3103 
 difference
   The syntax is
  \end_layout
- \begin_layout List
+ \begin_deeper
- \labelwidthstring 00000.00000.00000.000
+ \begin_layout LyX-Code
+ \family typewriter
+ first_set
+ \family default
  -
  \begin_inset LatexCommand \index{-, sets}
  \end_inset
  \family typewriter
- \InsetSpace ~
+  second_set
- \InsetSpace ~
- \InsetSpace ~
- first_set - second_set
  \end_layout
- \begin_deeper
  \begin_layout Standard
- For the sets A and B defined above, the set difference A - B is the set
+ For the sets
-  [1, 3, 5, 9] while the set difference B - A is the set [4, 6, 8].
+ \family typewriter
+ A
+ \family default
+  and
+ \family typewriter
+ B
+ \family default
+  defined above, the set difference
+ \family typewriter
+ A - B
+ \family default
+  is the set
+ \family typewriter
+ [1, 3, 5, 9]
+ \family default
+  while the set difference
+ \family typewriter
+ B - A
+ \family default
+  is the set
+ \family typewriter
+ [4, 6, 8]
+ \family default
+ .
  \end_layout
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  CARD
+ \family default
  \begin_inset LatexCommand \index{CARD}
  \end_inset
-Line 2712 
 CARD
+Line 3170 
 CARD
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  CHOICE
+ \family default
  \begin_inset LatexCommand \index{CHOICE}
  \end_inset
  [set] Choose one.
-  The result of running the CHOICE function over a set is an arbitrary (but
+  The result of running the
-  consistent: for any set instance you always get the same result) single
+ \family sans
-  element of that set.
+ CHOICE
+ \family default
+  function over a set is an arbitrary (but consistent: for any set instance
+  you always get the same result) single element of that set.
  \end_layout
  \begin_deeper
  \begin_layout Standard
- Running CHOICE[A] gives any member from the set A.
+ Running
+ \family typewriter
+ CHOICE[A]
+ \family default
+  gives any member from the set A.
   The result is a member, not a set.
   To make the result into a set, it must be enclosed in square brackets.
-  Thus [CHOICE[A]] is a set with a single element arbitrarily chosen from
+  Thus
-  the set A.
+ \family typewriter
+ [CHOICE[A]]
+ \family default
+  is a set with a single element arbitrarily chosen from the set A.
   Good modelers do not leave modeling decisions to the compiler; they do
-  not use CHOICE[].
+  not use
+ \family sans
+ CHOICE
+ \family default
+ .
   We are stuck with it for historical reasons.
  \end_layout
-Line 2751 
 A_less_one :== A - [CHOICE[A]];
+Line 3227 
 A_less_one :== A - [CHOICE[A]];
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  IN
+ \family default
  \begin_inset LatexCommand \index{IN}
  \end_inset
-  lhs IN rhs can only be well explained by examples.
-  IN is used in index expressions.
+ \family typewriter
-  If lhs is a simple and not previously defined name, it is created as a
+ lhs IN rhs
-  temporary loop index which will take on the values of the rhs set definition.
+ \family default
-  If lhs is something that already exists, the result of lhs IN rhs is a
+  can only be well explained by examples.
-  boolean value; stare at the model set_example below which demonstrates
-  both IN and SUCH_THAT.
+ \family sans
-  If you still are not satisfied, you might examine [[westerbergksets]].
+ IN
+ \family default
+  is used in index expressions.
+  If
+ \family typewriter
+ lhs
+ \family default
+  is a simple and not previously defined name, it is created as a temporary
+  loop index which will take on the values of the rhs set definition.
+  If lhs is something that already exists, the result of
+ \family typewriter
+ lhs IN rhs
+ \family default
+  is a boolean value; stare at the model
+ \family typewriter
+ set_example
+ \family default
+  below which demonstrates both
+ \family sans
+ IN
+ \family default
+  and
+ \family sans
+ SUCH_THAT
+ \family default
+ .
+  If you still are not satisfied, you might examine [[westerbergksets]]
+ \begin_inset Note Note
+ status open
+ \begin_layout Standard
+ fix this reference
+ \end_layout
+ \end_inset
+ .
  \end_layout
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  SUCH_THAT
+ \family default
  \begin_inset LatexCommand \index{SUCH\_THAT}
  \end_inset
- \InsetSpace ~
+  Set expressions can be rather clever.
- (*\InsetSpace ~
-\InsetSpace ~
- *) Set expressions can be rather clever.
   We will give a detailed example from chemistry because unordered sets are
   unfamiliar to most people and set arithmetic is quite powerful.
   In this example we see arrays of sets and sparse arrays.
-Line 2788 
 MODEL set_example;
+Line 3305 
 MODEL set_example;
  \end_layout
  \begin_layout LyX-Code
- (* we define a sparse matrix of reaction
+   (* we define a sparse matrix of reaction
  \end_layout
  \begin_layout LyX-Code
- coefficient information and the species
+      coefficient information and the species
  \end_layout
  \begin_layout LyX-Code
- balance equations.
+      balance equations.
   *)
  \end_layout
  \begin_layout LyX-Code
- rxns IS_A set OF integer_constant;
+   rxns IS_A set OF integer_constant;
  \end_layout
  \begin_layout LyX-Code
- rxns :== [1..3];
+   rxns :== [1..3];
  \end_layout
  \begin_layout LyX-Code
- species IS_A set OF symbol_constant;
+   species IS_A set OF symbol_constant;
  \end_layout
  \begin_layout LyX-Code
- species :== ['A','B','C','D'];
+   species :== ['A','B','C','D'];
  \end_layout
  \begin_layout LyX-Code
- reactants[rxns] IS_A set OF symbol_constant; (* species
+   reactants[rxns] IS_A set OF symbol_constant; (* species
  \end_layout
  \begin_layout LyX-Code
-    in each rxn_j *)
+      in each rxn_j *)
  \end_layout
  \begin_layout LyX-Code
- reactants[1] :== ['A','B','C'];
+   reactants[1] :== ['A','B','C'];
  \end_layout
  \begin_layout LyX-Code
- reactants[2] :== ['A','C'];
+   reactants[2] :== ['A','C'];
  \end_layout
  \begin_layout LyX-Code
- reactants[3] :== ['A','B','D'];
+   reactants[3] :== ['A','B','D'];
  \end_layout
  \begin_layout LyX-Code
- reactions[species] IS_A set OF integer_constant;
+   reactions[species] IS_A set OF integer_constant;
  \end_layout
  \begin_layout LyX-Code
- FOR i IN species CREATE (* rxns for each species i *)
+   FOR i IN species CREATE (* rxns for each species i *)
  \end_layout
  \begin_layout LyX-Code
- reactions[i] :== [j IN rxns SUCH_THAT i IN reactants[j]];
+     reactions[i] :== [j IN rxns SUCH_THAT i IN reactants[j]];
  \end_layout
  \begin_layout LyX-Code
- END FOR;
+   END FOR;
  \end_layout
  \begin_layout LyX-Code
- (* Define sparse stoichiometric matrix.
+   (* Define sparse stoichiometric matrix.
   Values of eta_ij
  \end_layout
  \begin_layout LyX-Code
-    set later.*)
+      set later.*)
  \end_layout
  \begin_layout LyX-Code
- FOR j IN rxns CREATE
+   FOR j IN rxns CREATE
  \end_layout
  \begin_layout LyX-Code
- FOR i IN reactants[j] CREATE
+     FOR i IN reactants[j] CREATE
  \end_layout
  \begin_layout LyX-Code
- (* eta_ij --> mole i/mole rxn j*)
+       (* eta_ij --> mole i/mole rxn j*)
  \end_layout
  \begin_layout LyX-Code
- eta[i][j] IS_A real_constant;
+       eta[i][j] IS_A real_constant;
  \end_layout
  \begin_layout LyX-Code
- END FOR;
+     END FOR;
  \end_layout
  \begin_layout LyX-Code
- END FOR;
+   END FOR;
  \end_layout
  \begin_layout LyX-Code
- production[species] IS_A molar_rate;
+   production[species] IS_A molar_rate;
  \end_layout
  \begin_layout LyX-Code
- rate[rxns] IS_A molar_rate; (* mole rxn j/time *)
+   rate[rxns] IS_A molar_rate; (* mole rxn j/time *)
  \end_layout
  \begin_layout LyX-Code
- FOR i IN species CREATE
+   FOR i IN species CREATE
  \end_layout
  \begin_layout LyX-Code
- gen_eqn[i]: production[i] =
+     gen_eqn[i]: production[i] =
  \end_layout
  \begin_layout LyX-Code
- SUM[eta[i][j]*rate[j] | j IN reactions[i]];
+     SUM[eta[i][j]*rate[j] | j IN reactions[i]];
  \end_layout
  \begin_layout LyX-Code
- END FOR;
+   END FOR;
  \end_layout
  \begin_layout LyX-Code
-Line 2915 
 END set_example;
+Line 3432 
 END set_example;
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
- "|
+ "
+ \family typewriter
+ |
+ \family default
  \begin_inset LatexCommand \index{|}
  \end_inset
- " is shorthand for SUCH_THAT.
+ " is shorthand for
+ \family sans
+ SUCH_THAT
+ \family default
+ .
  \end_layout
  \begin_deeper
  \begin_layout Standard
- The array eta has only 8 elements, and we defined those elements in a set
+ The array
-  for each reaction.
+ \family typewriter
-  The equation needs to know about the set of reactions for a species i,
+ eta
-  and that set is calculated automatically in the models first FOR/CREATE
+ \family default
+  has only 8 elements, and we defined those elements in a set for each reaction.
+  The equation needs to know about the set of reactions for a species
+ \family typewriter
+ i
+ \family default
+ , and that set is calculated automatically in the models first
+ \family sans
+ FOR/CREATE
+ \family default
   statement.
  \end_layout
- \end_deeper
- \begin_layout List
- \labelwidthstring 00000.00000.00000.000
- |
- \end_layout
- \begin_deeper
  \begin_layout Standard
- The | symbol is the ASCEND III notation for SUCH_THAT.
+ The
-  We noted that "|" is often read as "for all", which is different in that
+ \family typewriter
-  "for all" makes one think of a FOR loop where the loop index is on the
+ |
-  left of an IN operator.
+ \family default
-  For example, the j loop in the SUM of gen_eqn[i] above.
+  symbol is the ASCEND III notation for
+ \family sans
+ SUCH_THAT
+ \family default
+ .
+  We noted that "
+ \family typewriter
+ |
+ \family default
+ " is often read as "for all", which is different in that "for all" makes
+  one think of a
+ \family sans
+ FOR
+ \family default
+  loop where the loop index is on the left of an
+ \family sans
+ IN
+ \family default
+  operator.
+  For example, the
+ \family typewriter
+ j
+ \family default
+  loop in the
+ \family sans
+ SUM
+ \family default
+  of
+ \family typewriter
+ gen_eqn[i]
+ \family default
+  above.
  \end_layout
- \begin_layout Subsection
+ \begin_layout Section
  Constants
  \begin_inset LatexCommand \index{constants}
-Line 2962 
 Constants
+Line 3520 
 Constants
  ASCEND supports real, integer, boolean and character string constants.
   Constants in ASCEND do not have any attributes other than their value.
   Constants are scalar quantities that can be assigned exactly once.
-  Constants may only be assigned using the :== operator and the RHS expression
+  Constants may only be assigned using the
-  they are assigned from must itself be constant.
+ \family typewriter
+ :==
+ \family default
+  operator and the RHS expression they are assigned from must itself be constant.
   Constants do not have subparts.
   Integer and symbol constants may be used in determining the definitions
   of sets.
-Line 2986 
 Sets could be considered constant becaus
+Line 3547 
 Sets could be considered constant becaus
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  real_constant
+ \family default
  \begin_inset LatexCommand \index{real\_constant}
  \end_inset
-Line 3026 
 CONSTANT hydrogen_weight
+Line 3591 
 CONSTANT hydrogen_weight
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  integer_constant
+ \family default
  \begin_inset LatexCommand \index{integer\_constant}
  \end_inset
-Line 3034 
 integer_constant
+Line 3603 
 integer_constant
   Integer number.
   Principally used in determining model structure.
   If appearing in equations, integers are evaluated as dimensionless reals.
-  Typical use is inside a MODEL definition and looks like:
+  Typical use is inside a
+ \family sans
+ MODEL
+ \family default
+  definition and looks like:
  \end_layout
  \begin_deeper
-Line 3053 
 tray[1..n_trays] IS_A vl_equilibrium_tra
+Line 3626 
 tray[1..n_trays] IS_A vl_equilibrium_tra
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  symbol_constant
+ \family default
  \begin_inset LatexCommand \index{symbol\_constant}
  \end_inset
-Line 3064 
 symbol_constant
+Line 3641 
 symbol_constant
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  boolean_constant
+ \family default
  \begin_inset LatexCommand \index{boolean\_constant}
  \end_inset
-Line 3113 
 LHS_list :== RHS;
+Line 3694 
 LHS_list :== RHS;
  Here it is required that the one or more items in the LHS be of the same
   constant type and that RHS is a single-valued expression made up of values,
   operators, and other constants.
-  The :== is used to make clear to both the user and the system what scalar
+  The
-  objects are constants.
+ \family typewriter
+ :==
+ \family default
+  is used to make clear to both the user and the system what scalar objects
+  are constants.
  \end_layout
- \begin_layout Subsection
+ \begin_layout Section
  Variables
  \begin_inset LatexCommand \index{variables}
-Line 3131 
 Variables
+Line 3716 
 Variables
  There are four built-in types which may be used to construct variables:
   symbol, boolean, integer, and real.
   At this time symbol types have special restrictions.
-  Refinements of these variable base types are defined with the ATOM statement.
+  Refinements of these variable base types are defined with the
+ \family sans
+ ATOM
+ \family default
+  statement.
   Atom types may declare attribute fields with types real, integer, boolean,
   symbol, and set.
-  These attributes are NOT independent objects and therefore cannot be refined,
+  These attributes are
-  merged, or put in a refinement clique (ARE_ALIKEd).
+ \emph on
+ not
+ \emph default
+  independent objects and therefore cannot be refined, merged, or put in
+  a refinement clique (
+ \family sans
+ ARE_ALIKE
+ \family default
+ d).
  \end_layout
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  ATOM
+ \family default
  \begin_inset LatexCommand \index{ATOM}
  \end_inset
-Line 3195 
 atom_type_name
+Line 3796 
 atom_type_name
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  DEFAULT
+ \family default
  \begin_inset LatexCommand \index{DEFAULT}
  \end_inset
- ,\InsetSpace ~
+ ,
+ \family sans
+ \InsetSpace ~
  DIMENSION
+ \family default
  \begin_inset LatexCommand \index{DIMENSION}
  \end_inset
  ,\InsetSpace ~
  and\InsetSpace ~
+ \family sans
  DIMENSIONLESS
+ \family default
  \begin_inset LatexCommand \index{DIMENSIONLESS}
  \end_inset
-Line 3218 
 DIMENSIONLESS
+Line 3831 
 DIMENSIONLESS
  \begin_deeper
  \begin_layout Standard
- The DIMENSION attribute is for variables whose base type is real.
+ The
+ \family sans
+ DIMENSION
+ \family default
+  attribute is for variables whose base type is real.
   It is an optional field.
   If not defined for any atom with base type real, the dimensions will be
   left as undefined.
-Line 3232 
 The DIMENSION attribute is for variables
+Line 3849 
 The DIMENSION attribute is for variables
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  solver_var
+ \family default
  \begin_inset LatexCommand \index{solver\_var}
  \end_inset
-  is a special case of ATOM and we will say much more about it in Section
+  is a special case of
+ \family sans
+ ATOM
+ \family default
+  and we will say much more about it in Section
  \begin_inset LatexCommand \vref{sub:x.6.1Variables-for-solvers}
  \end_inset
-Line 3377 
 symbol
+Line 4001 
 symbol
  \end_inset
-  * 4 * Symbol valued variable quantity.
+  Symbol valued variable quantity.
   We do not yet have operators for building symbols out of other symbols.
  \end_layout
-Line 3451 
 We use an ordinary equals (=) when defin
+Line 4075 
 We use an ordinary equals (=) when defin
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \begin_inset Note Note
+ status open
+ \begin_layout List
+ \labelwidthstring 00000.00000.00000.000
  \bar under
  Tabular\InsetSpace ~
-Line 3473 
 assignments
+Line 4102 
 assignments
   Here are some examples:
  \end_layout
- \begin_deeper
  \begin_layout LyX-Code
  DATA ~(* ~4+ ~*)
  \end_layout
+ \begin_deeper
  \begin_layout LyX-Code
  MODEL tabular_ex;
  \end_layout
-Line 3605 
 For sparse arrays of variables or consta
+Line 4234 
 For sparse arrays of variables or consta
   along with the values to be assigned.
  \end_layout
- \begin_layout Subsection
+ \end_inset
+ \end_layout
+ \begin_deeper
+ \begin_layout Standard
+ \end_layout
+ \begin_layout Section
  Relations
  \begin_inset LatexCommand \index{relations}
-Line 3654 
 Each additive term in a mathematical exp
+Line 4293 
 Each additive term in a mathematical exp
  \begin_layout Standard
  An expression may contain an index variable as a part of the calculation
   if that index variable is over a set whose elements are of type integer.
-  (See the FOR/CREATE and FOR/DO statements below.) An example is:
+  (See the
+ \family sans
+ FOR/CREATE
+ \family default
+  and
+ \family sans
+ FOR/DO
+ \family default
+ statements below.) An example is:
  \end_layout
  \begin_layout LyX-Code
-Line 3716 
 objective_type LHS
+Line 4363 
 objective_type LHS
  \end_layout
  \begin_layout Standard
- Objective_type is either MAXIMIZE or MINIMIZE.
+ Objective_type is either
+ \family sans
+ MAXIMIZE
+ \family default
+  or
+ \family sans
+ MINIMIZE
+ \family default
+ .
   RHS and LHS must be one or more variables, constants, and operators in
   a normal algebraic expression.
   The operators allowed are defined below and in Section
-Line 3727 
 Objective_type is either MAXIMIZE or MIN
+Line 4382 
 Objective_type is either MAXIMIZE or MIN
  .
   Variable integers, booleans, and symbols are not allowed as operands in
   numerical relations, nor are boolean constants.
-  Integer indices declared in FOR/CREATE loops are allowed in relations,
+  Integer indices declared in
-  and they are treated as integer constants.
+ \family sans
+ FOR/CREATE
+ \family default
+  loops are allowed in relations, and they are treated as integer constants.
  \end_layout
  \end_deeper
-Line 3806 
 Equations must be dimensionally correct.
+Line 4464 
 Equations must be dimensionally correct.
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  MAXIMIZE
+ \family default
  \begin_inset LatexCommand \index{MAXIMIZE}
  \end_inset
  ,\InsetSpace ~
+ \family sans
  MINIMIZE
+ \family default
  \begin_inset LatexCommand \index{MINIMIZE}
  \end_inset
-Line 3945 
 Operators
+Line 4611 
 Operators
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family typewriter
  ordered_function
  \begin_inset LatexCommand \index{ordered\_function}
  \end_inset
- () unary real valued functions.
+ ()
+ \family default
+  unary real valued functions.
   The unary real functions we support are given in section Section
  \begin_inset LatexCommand \vref{sub:x.6.3Single-operand-real}
-Line 3972 
 terms:
+Line 4642 
 terms:
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  SUM
+ \family default
  \begin_inset LatexCommand \index{SUM}
  \end_inset
+ \family typewriter
  [term\InsetSpace ~
- set] Add all expressions in the functions list.
+ set]
+ \family default
+  Add all expressions in the functions list.
  \end_layout
  \begin_deeper
  \begin_layout Standard
- For the SUM, the base type real items can be arbitrary arithmetic expressions.
+ For the
+ \family sans
+ SUM
+ \family default
+ , the base type real items can be arbitrary arithmetic expressions.
   The resulting items must all be dimensionally compatible.
  \end_layout
-Line 4009 
 SUM[y[i] | i IN components] = 1;
+Line 4691 
 SUM[y[i] | i IN components] = 1;
  \bar under
  Empty\InsetSpace ~
- SUM[]\InsetSpace ~
+ \family sans
+ SUM
+ \family default
+ \InsetSpace ~
  yields\InsetSpace ~
- wild\InsetSpace ~
+ wildcard\InsetSpace ~
-.
+ \family typewriter
+ \family default
+ .
  \end_layout
  \begin_deeper
  \begin_layout Standard
- When a SUM is compiled over a list which is empty it generates a wild dimensione
+ When a
- d 0.
+ \family sans
+ SUM
+ \family default
+  is compiled over a list which is empty it generates a wildcard-dimensioned
+ \family typewriter
+ \family default
+ .
   This will sometimes cause our dimension checking routines to fail.
   The best way to prevent this is to make sure the SUM never actually encounters
   an empty list.
-Line 4030 
 SUM[Q[possibly_empty_set], 0{watt}];
+Line 4728 
 SUM[Q[possibly_empty_set], 0{watt}];
  \end_layout
  \begin_layout Standard
- In the above, the variables Q[i] (if they exist) have the dimensionality
+ In the above, the variables
-  associated with an energy rate.
+ \family typewriter
-  When the set is empty, the 0 is the only term in the SUM and establishes
+ Q[i]
-  the dimensionality of the result.
+ \family default
-  When the set is NOT empty the compiler will simplify away the trailing
+  (if they exist) have the dimensionality associated with an energy rate.
-in the sum.
+  When the set is empty, the
+ \family typewriter
+ \family default
+  is the only term in the
+ \family sans
+ SUM
+ \family default
+  and establishes the dimensionality of the result.
+  When the set is
+ \emph on
+ not
+ \emph default
+  empty the compiler will simplify away the trailing
+ \family typewriter
+ \family default
+  in the sum.
  \end_layout
  \end_deeper
-Line 4065 
 functions:
+Line 4780 
 functions:
  (Not implemented - only under confused consideration at this time.) The following
   functions only work in methods as they are not smooth function and would
   destroy a Newton-based solution algorithm if used in defining a model equation:
+ \begin_inset Note Note
+ status open
+ \begin_layout Standard
+ Clarification required
+ \end_layout
+ \end_inset
  \end_layout
  \end_deeper
-Line 4091 
 set] (* 4+ *) minimum value on list of a
+Line 4816 
 set] (* 4+ *) minimum value on list of a
  \end_layout
  \begin_deeper
- \begin_layout Subsection
+ \begin_layout Standard
+ \begin_inset Note Note
+ status open
+ \begin_layout Section
  Derivatives
  \begin_inset LatexCommand \index{derivatives}
  \end_inset
-  in relations (* 4+ *)
+  in relations
  \end_layout
  \begin_layout Standard
-Line 4110 
 Simply put, we would like to have genera
+Line 4839 
 Simply put, we would like to have genera
   work.
  \end_layout
- \begin_layout Subsection
+ \end_inset
+ \end_layout
+ \begin_layout Section
  External relations
  \begin_inset LatexCommand \index{relations, external}
-Line 4126 
 External relations
+Line 4860 
 External relations
  \begin_layout Standard
  We cannot document these at the present time.
-  The only reference for them is [[abbottthesis]].
+  Some details are available in Kirk Abbott's thesis
+ \begin_inset LatexCommand \cite{Abbott1996a}
+ \end_inset
+ , or check the wiki at
+ \family sans
+ http://ascendwiki.cheme.cmu.edu/
  \end_layout
- \begin_layout Subsection
+ \begin_layout Section
- Conditional relations
+ Conditional modelling
  \begin_inset LatexCommand \index{relations, conditional}
  \end_inset
-Line 4141 
 Conditional relations
+Line 4881 
 Conditional relations
  \end_inset
-  (* 4 *)
+ \end_layout
+ \begin_layout Subsection
+ Conditional relations
  \end_layout
  \begin_layout Standard
-Line 4163 
 END CONDITIONAL;
+Line 4907 
 END CONDITIONAL;
  \end_layout
  \begin_layout Standard
- A CONDITIONAL statement can appear anywhere in the declarative portion of
+ A
-  the model and it contains only relations to be used as boundaries.
+ \family sans
+ CONDITIONAL
+ \family default
+  statement can appear anywhere in the declarative portion of the model and
+  it contains only relations to be used as boundaries.
   That is, these real arithmetic equations are used in expressing logical
-  condition equations via the SATISFIED operator.
+  condition equations via the
+ \family sans
+ SATISFIED
+ \family default
+  operator.
  \end_layout
  \begin_layout Subsection
- Logical relations (* 4 *)
+ Logical relations
  \end_layout
  \end_deeper
-Line 4191 
 expression
+Line 4943 
 expression
  \end_inset
-  An expression whose value is TRUE or FALSE is a logical expression.
+  An expression whose value is
+ \family sans
+ TRUE
+ \family default
+  or
+ \family sans
+ FALSE
+ \family default
+  is a logical expression.
   Such expressions may contain boolean variables.
   If A,B, and laminar are boolean, then the following is a logical expression:
  \end_layout
-Line 4211 
 A OR (B AND laminar)
+Line 4971 
 A OR (B AND laminar)
  \begin_layout Standard
  The plus operator acts like an OR among the terms while the times operator
-  acts like an AND.
+  acts like an
-  Think of TRUE being equal to 1 and FALSE being equal to 0 with the 1+1=0+1=1+0=
+ \family sans
-, 0+0=0, 1*1=1 and 0*1=1*0=0*0=0.
+ AND
-  If A = FALSE, B=TRUE and laminar is TRUE, this expression has the value
+ \family default
+ .
+  Think of
+ \family sans
+ TRUE
+ \family default
+  being equal to 1 and
+ \family sans
+ FALSE
+ \family default
+  being equal to 0 with the 1+1=0+1=1+0=1, 0+0=0, 1*1=1 and 0*1=1*0=0*0=0.
+  If A =
+ \family sans
+ FALSE
+ \family default
+ , B=
+ \family sans
+ TRUE
+ \family default
+  and laminar is
+ \family sans
+ TRUE
+ \family default
+ , this expression has the value
  \end_layout
  \begin_layout LyX-Code
-Line 4231 
 or in terms of ones and zeros
+Line 5014 
 or in terms of ones and zeros
  \begin_layout Standard
  Logical relations are then made by putting together logical expressions
-  with the boolean relational operators == and !=.
+  with the boolean relational operators
+ \family typewriter
+ ==
+ \family default
+  and
+ \family typewriter
+ !=
+ \family default
+ .
   Since we have no logical solving engine we have not pushed the implementation
   of logical relations very hard yet.
  \end_layout
- \begin_layout Subsection
+ \begin_layout Section
+ \family sans
  NOTES
+ \family default
  \begin_inset LatexCommand \index{NOTES}
  \end_inset
-  (* 4 *)
- \end_layout
- \begin_layout Standard
- Within a MODEL (or METHOD) definition annotations (hereafter called notes)
-  may be made on a part declared in the MODEL, or on the MODEL (or METHOD)
-  itself.
-  Short notes may be made when defining or refining an object by enclosing
-  the note in "double quotes." Longer notes may be made in a block statement.
  \end_layout
  \begin_layout Standard
- Each note is entered in a database with the name of the file, name of MODEL,
+ Within a
-  name of METHOD if applicable, and the language (a kind of keyword) in which
+ \family sans
-  the note is written.
+ MODEL
-  Users, user interfaces, and other programs may query this database for
+ \family default
+  (or
+ \family sans
+ METHOD
+ \family default
+ ) definition annotations (hereafter called notes) may be made on a part
+  declared in the
+ \family sans
+ MODEL
+ \family default
+ , or on the
+ \family sans
+ MODEL
+ \family default
+  (or
+ \family sans
+ METHOD
+ \family default
+ ) itself.
+  Short notes may be made when defining or refining an object by enclosing
+  the note in double quotes (
+ \family typewriter
+ "
+ \family default
+ ).
+  Longer notes may be made in a block statement.
+ \end_layout
+ \begin_layout Standard
+ Each note is entered in a database with the name of the file, name of
+ \family sans
+ MODEL
+ \family default
+ , name of
+ \family sans
+ METHOD
+ \family default
+  if applicable, and the language (a kind of keyword) in which the note is
+  written.
+  Users, user interfaces, and other programs may query this database for
   information on models and simulations.
   The block notes may include code fragments in other languages that you
-  wish to embed in your MODEL or any other kind of text.
+  wish to embed in your
+ \family sans
+ MODEL
+ \family default
+  or any other kind of text.
  \end_layout
  \begin_layout Standard
-Line 4275 
 L[1..10] "L[i] is the length of the ith
+Line 5105 
 L[1..10] "L[i] is the length of the ith
  \end_layout
  \begin_layout LyX-Code
- IS_A distance;
+          IS_A distance;
  \end_layout
  \begin_layout LyX-Code
-Line 4287 
 thetaJ "angle between horizon and jupite
+Line 5117 
 thetaJ "angle between horizon and jupite
  \end_layout
  \begin_layout LyX-Code
- IS_A angle;
+          IS_A angle;
  \end_layout
  \begin_layout LyX-Code
-Line 4295 
 car.tires "using car in Minnesota, you b
+Line 5125 
 car.tires "using car in Minnesota, you b
  \end_layout
  \begin_layout LyX-Code
- IS_REFINED_TO snow_tire;
+          IS_REFINED_TO snow_tire;
  \end_layout
  \begin_layout Standard
- In the second IS_A statement concerning two angles, we see that a short
+ In the second
-  note in double quotes goes with the name immediately to its left.
+ \family sans
+ IS_A
+ \family default
+  statement concerning two angles, we see that a short note in double quotes
+  goes with the name immediately to its left.
   We also see that the note comes before the comma if the name is part of
   a list of names.
   In the third statement, we see that not only simple names but also qualified
-Line 4310 
 In the second IS_A statement concerning
+Line 5144 
 In the second IS_A statement concerning
  \begin_layout Standard
  Longer notes are made in block statements of the form below.
-  These blocks can appear in a METHOD or MODEL.
+  These blocks can appear in a
+ \family sans
+ METHOD
+ \family default
+  or
+ \family sans
+ MODEL
+ \family default
+ .
   These blocks can also be written separately before or after a model as
   we shall see.
  \end_layout
-Line 4320 
 NOTES
+Line 5162 
 NOTES
  \end_layout
  \begin_layout LyX-Code
- 'language or keyword' list.of, names {
+   'language or keyword' list.of, names {
  \end_layout
  \begin_layout LyX-Code
- free-form block of text to store in the
+     free-form block of text to store in the
  \end_layout
  \begin_layout LyX-Code
- database exactly as written.
+     database exactly as written.
  \end_layout
  \begin_layout LyX-Code
- }
+   }
  \end_layout
  \begin_layout LyX-Code
- some.other.name {
+   some.other.name {
  \end_layout
  \begin_layout LyX-Code
- this note has the same language or keyword as
+     this note has the same language or keyword as
  \end_layout
  \begin_layout LyX-Code
- the first since we didn't define a new keyword
+     the first since we didn't define a new keyword
  \end_layout
  \begin_layout LyX-Code
- in single quotes before the name list.
+     in single quotes before the name list.
  \end_layout
  \begin_layout LyX-Code
- }
+   }
  \end_layout
  \begin_layout LyX-Code
- 'another language' some.other.name {
+   'another language' some.other.name {
  \end_layout
  \begin_layout LyX-Code
- en espanol
+     en espanol
  \end_layout
  \begin_layout LyX-Code
- }
+   }
  \end_layout
  \begin_layout LyX-Code
- 'fortran' SELF {
+   'fortran' SELF {
  \end_layout
  \begin_layout LyX-Code
- This model should be solved with subroutine
+     This model should be solved with subroutine
  \end_layout
  \begin_layout LyX-Code
- LSODE.
+     LSODE.
  \end_layout
  \begin_layout LyX-Code
- This note demonstrates that "SELF" can be used
+     This note demonstrates that "SELF" can be used
  \end_layout
  \begin_layout LyX-Code
- to annotate the entire model instead of a
+     to annotate the entire model instead of a
  \end_layout
  \begin_layout LyX-Code
- named part.
+     named part.
  \end_layout
  \begin_layout LyX-Code
- }
+   }
  \end_layout
  \begin_layout LyX-Code
-Line 4409 
 ADD NOTES IN name_of_model;
+Line 5251 
 ADD NOTES IN name_of_model;
  \end_layout
  \begin_layout LyX-Code
- 'language or keyword' list.of, names {
+   'language or keyword' list.of, names {
  \end_layout
  \begin_layout LyX-Code
- more text
+     more text
  \end_layout
  \begin_layout LyX-Code
- } (* more than one note may be made in this
+   } (* more than one note may be made in this
  \end_layout
  \begin_layout LyX-Code
- block if desired.
+     block if desired.
   *)
  \end_layout
-Line 4430 
 END NOTES;
+Line 5272 
 END NOTES;
  \end_layout
  \begin_layout LyX-Code
- ADD NOTES IN name_of_model METHOD
+ ADD NOTES IN name_of_model METHOD name_of_method;
- \end_layout
- \begin_layout LyX-Code
- name_of_method;
  \end_layout
  \begin_layout LyX-Code
- 'language or keyword' SELF {
+   'language or keyword' SELF {
  \end_layout
  \begin_layout LyX-Code
- This method proves Fermat's last theorem and
+     This method proves Fermat's last theorem and
  \end_layout
  \begin_layout LyX-Code
- makes toast.
+     makes toast.
  \end_layout
  \begin_layout LyX-Code
- }
+   }
  \end_layout
  \begin_layout LyX-Code
- 'humor' SELF {
+   'humor' SELF {
  \end_layout
  \begin_layout LyX-Code
- ASCEND is not expected to make either proving
+     ASCEND is not expected to make either proving
  \end_layout
  \begin_layout LyX-Code
- FLT or toasting possible.
+     FLT or toasting possible.
  \end_layout
  \begin_layout LyX-Code
- }
+   }
  \end_layout
  \begin_layout LyX-Code
-Line 4512 
 Experience has shown that even documenta
+Line 5350 
 Experience has shown that even documenta
   code and documentation that results from undisciplined modeling.
  \end_layout
- \begin_layout Section
+ \begin_layout Chapter
  Declarative statements
  \begin_inset LatexCommand \index{statements, declarative}
-Line 4535 
 Declarative statements
+Line 5373 
 Declarative statements
  We have already seen several examples that included declarative statements.
   Here we will be more systematic in defining things.
   The statements we describe are legal within the declarative portion of
-  an ATOM or MODEL definition.
+  an
-  The declarative portion stops at the keyword METHODS if it is present in
+ \family sans
-  the definition or at the end of the definition.
+ ATOM
+ \family default
+  or
+ \family sans
+ MODEL
+ \family default
+  definition.
+  The declarative portion stops at the keyword
+ \family sans
+ METHODS
+ \family default
+  if it is present in the definition or at the end of the definition.
  \end_layout
  \end_deeper
-Line 4552 
 Statements
+Line 5401 
 Statements
  \end_inset
-  Statements in ASCEND terminate with a semicolon (;).
+  Statements in ASCEND terminate with a semicolon (
+ \family typewriter
+ ;
+ \family default
+ ).
   Statements may extend over any number of lines.
   They may have blank lines in the middle of them.
   There may be several statements on a single line.
-Line 4577 
 statements
+Line 5430 
 statements
  \end_inset
   Some statements in ASCEND can contain other statements as a part of them.
-  The declarative compound statements are the ALIASES/IS_A, CONDITIONAL,
+  The declarative compound statements are the
-  FOR/CREATE, SELECT/CASE, and WHEN/CASE statements.
+ \family sans
-  The procedural compound statements allowed only in methods are the FOR/DO,
+ ALIASES
-  FOR/CHECK, SWITCH (* 4 *) and the IF statements.
+ \family default
-  Compound statements end with "END word;", where word matches the beginning
+ /
-  of the syntax block, e.g.
+ \family sans
-  END FOR.and they can be nested, with some exceptions which are noted later.
+ IS_A
+ \family default
+ ,
+ \family sans
+ CONDITIONAL
+ \family default
+ ,
+ \family sans
+ FOR/CREATE
+ \family default
+ ,
+ \family sans
+ SELECT/CASE
+ \family default
+ , and
+ \family sans
+ WHEN/CASE
+ \family default
+  statements.
+  The procedural compound statements allowed only in methods are the
+ \family sans
+ FOR/DO
+ \family default
+ ,
+ \family sans
+ FOR/CHECK
+ \family default
+ ,
+ \family sans
+ SWITCH
+ \family default
+  and the
+ \family sans
+ IF
+ \family default
+  statements.
+  Compound statements end with "
+ \family sans
+ END
+ \family default
+ \family typewriter
+ word
+ \family default
+ ;", where word matches the beginning of the syntax block, e.g.
+ \family sans
+ END FOR
+ \family default
+ .and they can be nested, with some exceptions which are noted later.
  \end_layout
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  \bar under
- CASE\InsetSpace ~
+ CASE
+ \family default
+ \InsetSpace ~
  statements
  \bar default
-Line 4604 
 statements
+Line 5509 
 statements
  \end_inset
-  (*4*) WHEN/CASE, CONDITIONAL, and SELECT/CASE handle modeling alternatives
-  within a single definition.
+ \family sans
+ WHEN/CASE
+ \family default
+ ,
+ \family sans
+ CONDITIONAL
+ \family default
+ , and
+ \family sans
+ SELECT/CASE
+ \family default
+  handle modeling alternatives within a single definition.
   The easy way to remember the difference is that the first picks which equations
-  to solve WHEN discrete variables have certain values, while the second
+  to solve
-  SELECTs which statements to compile based on discrete constants.
+ \family sans
-  (* 4 *) SWITCH statements handle flow of control in methods, in a slightly
+ WHEN
-  more generalized form than the C language switch statement.
+ \family default
+  discrete variables have certain values, while the second
+ \family sans
+ SELECT
+ \family default
+ s which statements to compile based on discrete constants.
+  SWITCH statements handle flow of control in methods, in a slightly more
+  generalized form than the C language switch statement.
  \end_layout
  \begin_layout List
-Line 4631 
 declarations
+Line 5554 
 declarations
  \begin_deeper
  \begin_layout Standard
- MODEL and ATOM type definitions and METHOD definitions are not really compound
-  statements because they require a name following their END word that matches
+ \family sans
-  the name given at the beginning of the definition.
+ MODEL
+ \family default
+  and
+ \family sans
+ ATOM
+ \family default
+  type definitions and
+ \family sans
+ METHOD
+ \family default
+  definitions are not really compound statements because they require a name
+  following their
+ \family sans
+ END
+ \family default
+  word that matches the name given at the beginning of the definition.
   These definitions cannot be nested.
  \end_layout
-Line 4656 
 Well start with an extremely brief synop
+Line 5594 
 Well start with an extremely brief synop
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  IS_A
+ \family default
  \begin_inset LatexCommand \index{IS\_A}
  \end_inset
   Constructor.
   Calls for one or more named instances to be compiled using the type specified.
-  (* 4 *) If the type is one that requires parameters, the parameters must
+  If the type is one that requires parameters, the parameters must be supplied
-  be supplied in () following the type name.
+  in
+ \family typewriter
+ ()
+ \family default
+  following the type name.
  \end_layout
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  IS_REFINED_TO
+ \family default
  \begin_inset LatexCommand \index{IS\_REFINED\_TO}
  \end_inset
-Line 4678 
 IS_REFINED_TO
+Line 5628 
 IS_REFINED_TO
   Causes the already compiled instance(s) named to have their type changed
   to a more refined type.
   This causes an incremental recompilation of the instance(s).
-  IS_REFINED_TO is not a redefinition of the named instances because refinement
-  can only add compatible information.
+ \family sans
+ IS_REFINED_TO
+ \family default
+  is not a redefinition of the named instances because refinement can only
+  add compatible information.
   The instances retain all the structure that originally defined them.
-  (* 4 *) If the type being refined to requires arguments, these must be
+  If the type being refined to requires arguments, these must be supplied,
-  supplied, even if the same arguments were required in the IS_A of the originall
+  even if the same arguments were required in the
- y less refined declaration of the instance.
+ \family sans
+ IS_A
+ \family default
+  of the originally less refined declaration of the instance.
  \end_layout
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  ALIASES
+ \family default
  \begin_inset LatexCommand \index{ALIASES}
  \end_inset
- \InsetSpace ~
+  Part alternate naming statement.
- (*\InsetSpace ~
-\InsetSpace ~
- *) Part alternate naming statement.
   Establishes another name for an instance at the same scope or in a child
   instance.
-  The equivalent of an ALIASES in ASCEND III is to create another part with
+ \begin_inset Foot
-  the desired name and merge it immediately via ARE_THE_SAME with the part
+ status collapsed
-  being renamed, a rather expensive and unintuitive process.
+ \begin_layout Standard
+ The equivalent of an
+ \family sans
+ ALIASES
+ \family default
+  in ASCEND III was to create another part with the desired name and merge
+  it immediately via
+ \family sans
+ ARE_THE_SAME
+ \family default
+  with the part being renamed, a rather expensive and unintuitive process.
+ \end_layout
+ \end_inset
  \end_layout
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  ALIASES/IS_A
+ \family default
  \begin_inset LatexCommand \index{ALIASES/IS\_A}
  \end_inset
- \InsetSpace ~
- (*\InsetSpace ~
-\InsetSpace ~
- *)
  \end_layout
  \begin_deeper
-Line 4731 
 Creates an array of alternate names for
+Line 5706 
 Creates an array of alternate names for
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  WILL_BE
+ \family default
  \begin_inset LatexCommand \index{WILL\_BE}
  \end_inset
- \InsetSpace ~
+  Forward declaration statement.
- (*\InsetSpace ~
-\InsetSpace ~
- *) Forward declaration statement.
   Promises that a part with the given type will be constructed by an as yet
   unknown IS_A statement above the current scope.
-  At present WILL_BE is legal only in defining parameters.
+  At present
+ \family sans
+ WILL_BE
+ \family default
+  is legal only in defining parameters.
   Were it legal in the body of a model, compiling models would be very expensive.
  \end_layout
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  ARE_THE_SAME
+ \family default
  \begin_inset LatexCommand \index{ARE\_THE\_SAME}
  \end_inset
-Line 4764 
 ARE_THE_SAME
+Line 5748 
 ARE_THE_SAME
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  WILL_BE_THE_SAME
+ \family default
  \begin_inset LatexCommand \index{WILL\_BE\_THE\_SAME}
  \end_inset
- \InsetSpace ~
- (*\InsetSpace ~
-\InsetSpace ~
- *)
  \end_layout
  \begin_deeper
-Line 4786 
 d.
+Line 5771 
 d.
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  WILL_NOT_BE_THE_SAME
+ \family default
  \begin_inset LatexCommand \index{WILL\_NOT\_BE\_THE\_SAME}
  \end_inset
- \InsetSpace ~
- (*\InsetSpace ~
-\InsetSpace ~
- *)
  \end_layout
  \begin_deeper
-Line 4811 
 Structural condition statement restricti
+Line 5797 
 Structural condition statement restricti
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \begin_inset Note Note
+ status open
+ \begin_layout List
+ \labelwidthstring 00000.00000.00000.000
+ \family sans
  ARE_NOT_THE_SAME
+ \family default
  \begin_inset LatexCommand \index{ARE\_NOT\_THE\_SAME}
  \end_inset
- \InsetSpace ~
- (*\InsetSpace ~
-+\InsetSpace ~
- *)
  \end_layout
- \begin_deeper
  \begin_layout Standard
  Cannot be merged.
   We believe it is useful to say that two objects cannot be merged and still
-Line 4831 
 Cannot be merged.
+Line 5822 
 Cannot be merged.
   The implementation is simple.
  \end_layout
- \end_deeper
+ \end_inset
+ \end_layout
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  ARE_ALIKE
+ \family default
  \begin_inset LatexCommand \index{ARE\_ALIKE}
  \end_inset
-Line 4854 
 ARE_ALIKE
+Line 5853 
 ARE_ALIKE
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  FOR/CREATE
+ \family default
  \begin_inset LatexCommand \index{FOR/CREATE}
  \end_inset
-Line 4865 
 FOR/CREATE
+Line 5868 
 FOR/CREATE
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  FOR/CHECK
+ \family default
  \begin_inset LatexCommand \index{FOR/CHECK}
  \end_inset
-Line 4880 
 FOR/CHECK
+Line 5887 
 FOR/CHECK
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  SELECT/CASE
+ \family default
  \begin_inset LatexCommand \index{SELECT/CASE}
  \end_inset
- \InsetSpace ~
- (*\InsetSpace ~
-\InsetSpace ~
- *)
  \end_layout
  \begin_deeper
  \begin_layout Standard
  Select a subset of statements to compile.
-  Given the values of the specified constants, SELECT compiles all cases
+  Given the values of the specified constants,
-  that match those values.
+ \family sans
-  A name cannot be defined two different ways inside the SELECT statement,
+ SELECT
-  but it may be defined outside the case statement and then refined in different
+ \family default
-  ways in separate cases.
+  compiles all cases that match those values.
+  A name cannot be defined two different ways inside the
+ \family sans
+ SELECT
+ \family default
+  statement, but it may be defined outside the case statement and then refined
+  in different ways in separate cases.
  \end_layout
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  CONDITIONAL
+ \family default
  \begin_inset LatexCommand \index{CONDITIONAL}
  \end_inset
- \InsetSpace ~
- (*\InsetSpace ~
-\InsetSpace ~
- *)
  \end_layout
  \begin_deeper
  \begin_layout Standard
  Describe bounding relations.
-  The relations written inside a CONDITIONAL statement must all be labelled.
+  The relations written inside a
+ \family sans
+ CONDITIONAL
+ \family default
+  statement must all be labelled.
   These relations can be used to define regions in which alternate sets of
-  equations apply using the WHEN statement.
+  equations apply using the
+ \family sans
+ WHEN
+ \family default
+  statement.
  \end_layout
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  WHEN/CASE
+ \family default
  \begin_inset LatexCommand \index{WHEN/CASE}
  \end_inset
- \InsetSpace ~
+  When logical variables have certain values, use certain relations or model
- (*\InsetSpace ~
+  parts in defining a mathematical problem.
-\InsetSpace ~
- *) When logical variables have certain values, use certain relations
-  or model parts in defining a mathematical problem.
   The relations are not defined inside the WHEN statement because all the
   relations must be compiled regardless of which values the logical variables
   have at any given moment.
-Line 5701 
 END FOR;
+Line 6725 
 END FOR;
  \end_layout
  \begin_layout Standard
- FOR loops can be nested to produce sparse arrays as illustrated in Arrays
-  can be jagged(
+ \family sans
+ FOR
+ \family default
+  loops can be nested to produce sparse arrays as illustrated in Arrays can
+  be jagged(
  \begin_inset LatexCommand \vpageref{lyx:Arrays-can-be}
  \end_inset
-Line 5715 
 FOR loops can be nested to produce spars
+Line 6743 
 FOR loops can be nested to produce spars
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  SELECT/CASE
+ \family default
  \begin_inset LatexCommand \index{SELECT/CASE}
  \end_inset
- \InsetSpace ~
- (*\InsetSpace ~
-\InsetSpace ~
- *)
  \end_layout
  \begin_deeper
-Line 5731 
 SELECT/CASE
+Line 6760 
 SELECT/CASE
  Declarative.
   Order does not matter.
   All matching cases are executed.
-  The OTHERWISE
+  The
+ \family sans
+ OTHERWISE
+ \family default
  \begin_inset LatexCommand \index{OTHERWISE}
  \end_inset
-  is executed if present and no other CASEs match.
+  is executed if present and no other
-  SELECT is not allowed inside FOR.
+ \family sans
-  Writing FOR statements inside SELECT is allowed.
+ CASE
+ \family default
+ s match.
+ \family sans
+ SELECT
+ \family default
+  is not allowed inside
+ \family sans
+ FOR
+ \family default
+ .
+  Writing
+ \family sans
+ FOR
+ \family default
+  statements inside
+ \family sans
+ SELECT
+ \family default
+  is allowed.
  \end_layout
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  CONDITIONAL
+ \family default
  \begin_inset LatexCommand \index{CONDITIONAL}
  \end_inset
- \InsetSpace ~
- (*\InsetSpace ~
-\InsetSpace ~
- *)
  \end_layout
  \begin_deeper
  \begin_layout Standard
- Both real and logical relations are allowed in CONDITIONAL statements.
+ Both real and logical relations are allowed in
-  CONDITIONAL is really just a shorthand for setting the $boundary flag on
+ \family sans
-  a whole batch of relations, since $boundary is a write-once attribute invisible
+ CONDITIONAL
-  through the user interface and methods at this time.
+ \family default
+  statements.
+ \begin_inset Foot
+ status open
+ \begin_layout Standard
+ \family sans
+ CONDITIONAL
+ \family default
+  is really just a shorthand for setting the
+ \family typewriter
+ $boundary
+ \family default
+  flag on a whole batch of relations, since
+ \family typewriter
+ $boundary
+ \family default
+  is a write-once attribute invisible through the user interface and methods
+  at this time.
+ \end_layout
+ \end_inset
  \end_layout
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  WHEN/CASE
+ \family default
  \begin_inset LatexCommand \index{WHEN/CASE}
  \end_inset
- \InsetSpace ~
+  Inside each
- (*\InsetSpace ~
+ \family sans
-\InsetSpace ~
+ CASE
- *) Inside each CASE, relations or model parts to be used are specified
+ \family default
-  by writing, for example, USE mass_balance_1;.
+ , relations or model parts to be used are specified by writing, for example,
+ \family typewriter
+ USE mass_balance_1;
+ \family default
+ .
   The method of dealing with the combined logical/nonlinear model is left
   to the solver.
-  All matching CASEs are included in the problem to be solved.
+  All matching
+ \family sans
+ CASE
+ \family default
+ s are included in the problem to be solved.
  \end_layout
  \begin_deeper
- \begin_layout Section
+ \begin_layout Chapter
  Procedural statements
  \begin_inset LatexCommand \index{statements, procedural}
-Line 5805 
 Procedural statements
+Line 6896 
 Procedural statements
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  METHODS
+ \family default
  \begin_inset LatexCommand \index{METHODS}
  \end_inset
-Line 5824 
 METHODS
+Line 6919 
 METHODS
  \begin_layout Standard
  with no punctuation.
-  The next code must be a METHOD or the END of the type being defined.
+  The next code must be a
+ \family sans
+ METHOD
+ \family default
+  or the
+ \family sans
+ END
+ \family default
+  of the type being defined.
   If there are no method definitions, this statement may be omitted.
  \end_layout
  \begin_layout Standard
- METHOD definitions for a type can also be added or replaced after the type
-  has been defined.
+ \family sans
+ METHOD
+ \family default
+  definitions for a type can also be added or replaced after the type has
+  been defined.
   This is to make creating and debugging of methods as interactive as possible.
-  In ASCEND III an instance must be destroyed and recreated each time a new
+  In ASCEND an instance must be destroyed and recreated each time a new or
-  or revised method is added to the type definition.
+  revised method is added to the type definition.
   This is a very expensive process when working with models of significant
   size.
  \end_layout
-Line 5846 
 The detailed semantics of method inherit
+Line 6953 
 The detailed semantics of method inherit
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  ADD\InsetSpace ~
  METHODS\InsetSpace ~
  IN
+ \family default
  \begin_inset LatexCommand \index{ADD METHODS IN}
  \end_inset
+ \family typewriter
  \InsetSpace ~
- type_name;\InsetSpace ~
+ type_name;
- (*\InsetSpace ~
-\InsetSpace ~
- *)
  \end_layout
  \begin_deeper
-Line 5878 
 e rules.
+Line 6988 
 e rules.
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  REPLACE\InsetSpace ~
  METHODS\InsetSpace ~
  IN
+ \family default
  \begin_inset LatexCommand \index{REPLACE METHODS IN}
  \end_inset
+ \family typewriter
  \InsetSpace ~
- type_name;\InsetSpace ~
+ type_name;
- (*\InsetSpace ~
-\InsetSpace ~
- *)
  \end_layout
  \begin_deeper
  \begin_layout Standard
  This statement allows existing methods to be replaced in an already loaded
   type definition.
-  The next code must be a METHOD or the END METHODS; statement.
+  The next code must be a
-  If a method of the same name does not exist in type_name, the statement
+ \family sans
-  is in error.
+ METHOD
-  If other types refine type_name then the replacement follows the method
+ \family default
-  inheritance rules.
+  or the
+ \family sans
+ END METHODS
+ \family default
+  statement.
+  If a method of the same name does not exist in
+ \family typewriter
+ type_name
+ \family default
+ , the statement is in error.
+  If other types refine
+ \family typewriter
+ type_name
+ \family default
+  then the replacement follows the method inheritance rules.
   Any type which inherited the old method now inherits the replacment method
   instead.
  \end_layout
-Line 5908 
 This statement allows existing methods t
+Line 7035 
 This statement allows existing methods t
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  ADD\InsetSpace ~
  METHODS\InsetSpace ~
  IN\InsetSpace ~
  DEFINITION\InsetSpace ~
- MODEL;
+ MODEL
+ \family typewriter
+ ;
  \end_layout
  \begin_deeper
  \begin_layout Standard
  This statement allows methods to be added globally.
   It should be used very sparingly.
-  Library basemodel.a4l contains the example of this statement.
+  Library
+ \family typewriter
+ basemodel.a4l
+ \family default
+  contains the example of this statement.
   Methods in the global model definition are inherited by all models.
   There is no actual global model definition, but it has a method list for
   practical purposes.
-Line 5964 
 METHOD
+Line 7099 
 METHOD
  At present, there are no local variables or other structures in methods
   except loop indices.
   A method may be written recursively, but there is an arbitrary stack depth
-  limit (currently set to 20 in compiler/initialize.h) to prevent the system
+  limit
-  from crashing on infinite recursions.
+ \begin_inset Foot
+ status open
+ \begin_layout Standard
+ currently set to 20 in
+ \family typewriter
+ compiler/initialize.h
+ \end_layout
+ \end_inset
+  to prevent the system from crashing on infinite recursions.
  \end_layout
  \begin_layout Standard
- Specifically disallowed in ASCEND III methods are IS_A, ALIASES, WILL_BE,
+ Specifically disallowed in ASCEND methods are
-  IS, IS_REFINED_TO, ARE_THE_SAME and ARE_ALIKE statements as these declare
+ \family sans
-  the structure of the model and belong only in the declarative section.
+ IS_A
+ \family default
+ ,
+ \family sans
+ ALIASES
+ \family default
+ ,
+ \family sans
+ WILL_BE
+ \family default
+ ,
+ \family sans
+ IS
+ \family default
+ ,
+ \family sans
+ IS_REFINED_TO
+ \family default
+ ,
+ \family sans
+ ARE_THE_SAME
+ \family default
+  and
+ \family sans
+ ARE_ALIKE
+ \family default
+  statements as these declare the structure of the model and belong only
+  in the declarative section.
  \end_layout
  \begin_layout Standard
+ \begin_inset Note Note
+ status open
+ \begin_layout Standard
  (* 4+ *) In the near future, declarations of local instances (which are
   automatically destroyed when the method exits) will be allowed.
   Since methods are imperative, these local structure definitions are processed
-Line 5988 
 Specifically disallowed in ASCEND III me
+Line 7165 
 Specifically disallowed in ASCEND III me
   to use as the declarative ASCEND language.
  \end_layout
+ \end_inset
+ \end_layout
  \begin_layout Standard
  The syntax for a method declaration is
  \end_layout
-Line 6085 
 Its meaning is that the value for the va
+Line 7267 
 Its meaning is that the value for the va
  \end_layout
  \begin_layout Standard
- DATA (* 4+ *) statements can (should, rather) also appear in methods.
+ \family sans
+ DATA
+ \family default
+  statements can (should, rather) also appear in methods.
  \end_layout
-Line 6102 
 FOR/DO
+Line 7288 
 FOR/DO
  \begin_deeper
  \begin_layout Standard
- This statement is similar to the FOR/CREATE statement except it can only
+ This statement is similar to the
-  appear in a method definition.
+ \family sans
+ FOR/CREATE
+ \family default
+  statement except it can only appear in a method definition.
   An example would be
  \end_layout
-Line 6124 
 END FOR;
+Line 7313 
 END FOR;
  \end_layout
  \begin_layout Standard
- Here we actually execute using the values of i in the sequence given.
+ Here we actually execute using the values of
+ \family typewriter
+ i
+ \family default
+  in the sequence given.
   So,
  \end_layout
-Line 6157 
 is a backward loop.
+Line 7350 
 is a backward loop.
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  IF
+ \family default
  \begin_inset LatexCommand \index{IF}
  \end_inset
-Line 6167 
 IF
+Line 7364 
 IF
  \begin_deeper
  \begin_layout Standard
- The IF statement can only appear in a method definition.
+ The
+ \family sans
+ IF
+ \family default
+ statement can only appear in a method definition.
   Its syntax is
  \end_layout
-Line 6222 
 END IF;
+Line 7423 
 END IF;
  \end_layout
  \begin_layout Standard
- If the logical expression has a value of TRUE, ASCEND will execute the statement
+ If the logical expression has a value of
- s in the THEN part.
+ \family sans
-  If the value is FALSE, ASCEND executes the statements in the optional ELSE
+ TRUE
+ \family default
+ , ASCEND will execute the statements in the
+ \family sans
+ THEN
+ \family default
   part.
-  Please use () to make the precedence of AND, OR, NOT, ==, and != clear
+  If the value is
-  to both the user and the system.
+ \family sans
+ FALSE
+ \family default
+ , ASCEND executes the statements in the optional
+ \family sans
+ ELSE
+ \family default
+  part.
+  Please use
+ \family typewriter
+ ()
+ \family default
+  to make the precedence of
+ \family sans
+ AND
+ \family default
+ ,
+ \family sans
+ OR
+ \family default
+ ,
+ \family sans
+ NOT
+ \family default
+ ,
+ \family typewriter
+ ==
+ \family default
+ , and
+ \family typewriter
+ !=
+ \family default
+  clear to both the user and the system.
  \end_layout
  \end_deeper
  \begin_layout List
  \labelwidthstring 00000.00000.00000.000
+ \family sans
  SWITCH
+ \family default
  \begin_inset LatexCommand \index{SWITCH}
  \end_inset
- \InsetSpace ~
+  Essentially roughly equivalent to the C
- (*\InsetSpace ~
+ \family typewriter
-\InsetSpace ~
+ switch
- *) Essentially roughly equivalent to the C switch statement, except that
+ \family default
-  ASCEND allows wildcard matches, allows any number of controlling variables
+  statement, except that ASCEND allows wildcard matches, allows any number
-  to be given in a list, and assumes BREAK at the end of each CASE.
+  of controlling variables to be given in a list, and assumes
+ \family sans
+ BREAK
+ \family default
+  at the end of each
+ \family sans
+ CASE
+ \family default
+ .
  \end_layout
+ \begin_deeper
+ \begin_layout List
+ \labelwidthstring 00000.00000.00000.000