models/johnpye/newton.a4c

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

(* 
	Simple dynamic model of object under gravity (for use in test suite)
*)
MODEL newton;
	x IS_A distance;
	dx_dt IS_A speed;
	v IS_A speed;
	dv_dt IS_A acceleration;
	g IS_A gravity_constant;
	g :== 1{EARTH_G};

	xderiv: dx_dt = v;
	vderiv: dv_dt = -g;
	
	t IS_A time;
METHODS

METHOD values;
	v := +10 {m/s};
	x := 0 {m};
	t := 0 {s};
END values;

METHOD specify;
	FIX x, v;
END specify;

METHOD ode_init;
	FREE x,v;
	t.ode_type := -1; t := 0 {s};
	dx_dt.ode_id := 1; x.ode_id := 1; dx_dt.ode_type := 2; x.ode_type := 1;
	dv_dt.ode_id := 2; v.ode_id := 2; dv_dt.ode_type := 2; v.ode_type := 1;
	x.obs_id := 1;
	v.obs_id := 2;
	dv_dt.obs_id := 3;
	v.ode_atol := 1e-8;
	x.ode_atol := 1e-8;
END ode_init;
	
METHOD on_load;
	RUN reset; RUN values;
	RUN ode_init;
END on_load;

METHOD self_test;
	(* assumes integration up to t = (20/9.8){s}; *)
	ASSERT abs(x - 0 {m}) < 1e-5 {m};
	ASSERT abs(v +10 {m/s}) < 1e-5 {m/s};
	ASSERT abs(dv_dt + g) == 0 {m/s^2};
END self_test;

END newton;
1	REQUIRE "ivpsystem.a4l";
2	REQUIRE "atoms.a4l";
3
4	(*
5	Simple dynamic model of object under gravity (for use in test suite)
6	*)
7	MODEL newton;
8	x IS_A distance;
9	dx_dt IS_A speed;
10	v IS_A speed;
11	dv_dt IS_A acceleration;
12	g IS_A gravity_constant;
13	g :== 1{EARTH_G};
14
15	xderiv: dx_dt = v;
16	vderiv: dv_dt = -g;
17
18	t IS_A time;
19	METHODS
20
21	METHOD values;
22	v := +10 {m/s};
23	x := 0 {m};
24	t := 0 {s};
25	END values;
26
27	METHOD specify;
28	FIX x, v;
29	END specify;
30
31	METHOD ode_init;
32	FREE x,v;
33	t.ode_type := -1; t := 0 {s};
34	dx_dt.ode_id := 1; x.ode_id := 1; dx_dt.ode_type := 2; x.ode_type := 1;
35	dv_dt.ode_id := 2; v.ode_id := 2; dv_dt.ode_type := 2; v.ode_type := 1;
36	x.obs_id := 1;
37	v.obs_id := 2;
38	dv_dt.obs_id := 3;
39	v.ode_atol := 1e-8;
40	x.ode_atol := 1e-8;
41	END ode_init;
42
43	METHOD on_load;
44	RUN reset; RUN values;
45	RUN ode_init;
46	END on_load;
47
48	METHOD self_test;
49	(* assumes integration up to t = (20/9.8){s}; *)
50	ASSERT abs(x - 0 {m}) < 1e-5 {m};
51	ASSERT abs(v +10 {m/s}) < 1e-5 {m/s};
52	ASSERT abs(dv_dt + g) == 0 {m/s^2};
53	END self_test;
54
55	END newton;