models/johnpye/idadenx.a4c

REQUIRE "ivpsystem.a4l";
REQUIRE "atoms.a4l";

IMPORT "johnpye/extpy/extpy";
IMPORT "johnpye/solve";

(*
	ASCEND model based on the 'idadenx.c' example problem that accompanies IDA.
	The root-finding part isn't yet implemented though.
    ----------------------------------------------------------------------------
	This simple example problem for IDA, due to Robertson, 
	is from chemical kinetics, and consists of the following three 
	equations:

	     dy1/dt = -.04*y1 + 1.e4*y2*y3
	     dy2/dt = .04*y1 - 1.e4*y2*y3 - 3.e7*y2**2
	        0   = y1 + y2 + y3 - 1

	on the interval from t = 0.0 to t = 4.e10, with initial
	conditions: y1 = 1, y2 = y3 = 0.

	This model is tested (using the same parameters as used by idadenx.c) by the
	script pygtk/test.py.
*)
MODEL idadenx;
	y1, y2, y3 IS_A factor;
	dy1_dt IS_A factor;
	dy2_dt IS_A factor;

	eq1: dy1_dt = -0.04 * y1 + 1e4 * y2*y3;
	eq2: dy2_dt = +0.04 * y1 - 1e4 * y2*y3 - 3e7*y2^2;
	eq3: 0 = y1 + y2 + y3 - 1;
	
	t IS_A time;
METHODS

METHOD values; (* initial values *)
	y1 := 1;
	y2 := 0;
	y3 := 0;
	t := 0 {s};
END values;

METHOD specify;
	FIX y1, y2;
END specify;

METHOD ode_init;
	FREE y1, y2;
	t.ode_type := -1; t := 0 {s};
	dy1_dt.ode_id := 1; dy1_dt.ode_type := 2;
	y1.ode_id := 1; y1.ode_type := 1;

	dy2_dt.ode_id := 2; dy2_dt.ode_type := 2;
	y2.ode_id := 2; y2.ode_type := 1;

	y3.ode_id := 3;

	t.obs_id := 1;
	y1.obs_id := 2;
	y2.obs_id := 3;
	y3.obs_id := 4;
	dy1_dt.obs_id := 5;
	dy2_dt.obs_id := 6;

	y1.ode_atol := 1e-8;
	y2.ode_atol := 1e-14;
	y3.ode_atol := 1e-6;
END ode_init;
	
METHOD on_load;
	RUN reset; RUN values;
	EXTERNAL solve(SELF);
	RUN ode_init;
END on_load;

END idadenx;
1	REQUIRE "ivpsystem.a4l";
2	REQUIRE "atoms.a4l";
3
4	IMPORT "johnpye/extpy/extpy";
5	IMPORT "johnpye/solve";
6
7	(*
8	ASCEND model based on the 'idadenx.c' example problem that accompanies IDA.
9	The root-finding part isn't yet implemented though.
10	----------------------------------------------------------------------------
11	This simple example problem for IDA, due to Robertson,
12	is from chemical kinetics, and consists of the following three
13	equations:
14
15	dy1/dt = -.04y1 + 1.e4y2*y3
16	dy2/dt = .04y1 - 1.e4y2y3 - 3.e7y2**2
17	0 = y1 + y2 + y3 - 1
18
19	on the interval from t = 0.0 to t = 4.e10, with initial
20	conditions: y1 = 1, y2 = y3 = 0.
21
22	This model is tested (using the same parameters as used by idadenx.c) by the
23	script pygtk/test.py.
24	*)
25	MODEL idadenx;
26	y1, y2, y3 IS_A factor;
27	dy1_dt IS_A factor;
28	dy2_dt IS_A factor;
29
30	eq1: dy1_dt = -0.04 * y1 + 1e4 * y2*y3;
31	eq2: dy2_dt = +0.04 * y1 - 1e4 * y2y3 - 3e7y2^2;
32	eq3: 0 = y1 + y2 + y3 - 1;
33
34	t IS_A time;
35	METHODS
36
37	METHOD values; (* initial values *)
38	y1 := 1;
39	y2 := 0;
40	y3 := 0;
41	t := 0 {s};
42	END values;
43
44	METHOD specify;
45	FIX y1, y2;
46	END specify;
47
48	METHOD ode_init;
49	FREE y1, y2;
50	t.ode_type := -1; t := 0 {s};
51	dy1_dt.ode_id := 1; dy1_dt.ode_type := 2;
52	y1.ode_id := 1; y1.ode_type := 1;
53
54	dy2_dt.ode_id := 2; dy2_dt.ode_type := 2;
55	y2.ode_id := 2; y2.ode_type := 1;
56
57	y3.ode_id := 3;
58
59	t.obs_id := 1;
60	y1.obs_id := 2;
61	y2.obs_id := 3;
62	y3.obs_id := 4;
63	dy1_dt.obs_id := 5;
64	dy2_dt.obs_id := 6;
65
66	y1.ode_atol := 1e-8;
67	y2.ode_atol := 1e-14;
68	y3.ode_atol := 1e-6;
69	END ode_init;
70
71	METHOD on_load;
72	RUN reset; RUN values;
73	EXTERNAL solve(SELF);
74	RUN ode_init;
75	END on_load;
76
77	END idadenx;