(*	ASCEND modelling environment
	Copyright (C) 1996  Carnegie Mellon University
	Copyright (C) 2006 Carnegie Mellon University

	This program is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2, or (at your option)
	any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.
	
	You should have received a copy of the GNU General Public License
	along with this program.  If not, see <http://www.gnu.org/licenses/>.
*)
REQUIRE "system.a4l";
IMPORT "sensitivity/sensitivity";
(*
	A very simple test model for the external sensitivity analysis
	module.

	by Ben Allan, 1996
	Self-testing added by John Pye, 2007

	--- old comments (don't seem to be accurate) ---

	This module is used to calculate the sensitity matrix dX/dU where
	X is a vector OF vapor compositions and U is a vector OF liquid
	compositions. This sensitivity matrix is THEN used to calculate
	J, the Jacobian, as described IN Fidkowski et al. (1995).
*)

MODEL sensitivity_test;
	nc IS_A integer_constant;
	X[1..nc] IS_A solver_var;
	U[1..nc] IS_A solver_var;
	dx_du[1..nc][1..nc] IS_A solver_var;

	(* system for investigation *)
	k,x,y,u IS_A solver_var;
	k*x - y = 7;
	y = u^2; 
	(* hence, dx/du = 2*u/k *)

	nc:==1;
	u,U[1] ARE_THE_SAME;
	x,X[1] ARE_THE_SAME;

METHODS
	METHOD values;
		FOR j IN [1..nc] DO
			U[j] := j;
		END FOR;
	END values;

	METHOD specify;
		FIX u, k;
	END specify;

	METHOD on_load;
		RUN reset;
		RUN values;
	END on_load;

	METHOD analyse;
	  EXTERNAL do_sensitivity(SELF,U[1..nc],X[1..nc],dx_du[1..nc][1..nc]);
	END analyse;

	METHOD self_test;
		FOR i IN [1..nc] DO (* X[i] *)
			FOR j IN [1..nc] DO (* U[j] *)
				ASSERT abs(dx_du[i][j] - 2*U[j]/k) < 0.00001 * 2 * U[j]/k;
			END FOR;
		END FOR;
	END self_test;
END sensitivity_test;

MODEL sensitivity_test_all REFINES sensitivity_test;
	U_new[1..nc] IS_A real;
	stepsize IS_A real_constant;
	stepsize :== 0.0001;
METHODS
	METHOD analyse;
		EXTERNAL do_sensitivity_all(SELF,U[1..nc],U_new[1..nc],stepsize);
	END analyse;

	METHOD self_test;
		ASSERT 1==0;
	END self_test;
END sensitivity_test_all;