models/johnpye/newton.a4c

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

(* 
	Simple dynamic model of object under gravity (for use in test suite).
	We expect an inverted parabola. Check that after the expected elapsed time,
	x returns to its starting value and velocity is the negative of the starting
	value.
*)
MODEL newton;
	x IS_A distance;
	dx_dt IS_A speed;
	v IS_A speed;
	dv_dt IS_A acceleration;
	g IS_A real_constant;
	g :== 10{N/kg};

	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;
	t.obs_id := 1;
	x.obs_id := 2;
	v.obs_id := 3;
	dv_dt.obs_id := 4;
	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) < 1e-10 {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	We expect an inverted parabola. Check that after the expected elapsed time,
7	x returns to its starting value and velocity is the negative of the starting
8	value.
9	*)
10	MODEL newton;
11	x IS_A distance;
12	dx_dt IS_A speed;
13	v IS_A speed;
14	dv_dt IS_A acceleration;
15	g IS_A real_constant;
16	g :== 10{N/kg};
17
18	xderiv: dx_dt = v;
19	vderiv: dv_dt = -g;
20
21	t IS_A time;
22	METHODS
23
24	METHOD values;
25	v := +10 {m/s};
26	x := 0 {m};
27	t := 0 {s};
28	END values;
29
30	METHOD specify;
31	FIX x, v;
32	END specify;
33
34	METHOD ode_init;
35	FREE x,v;
36	t.ode_type := -1; t := 0 {s};
37	dx_dt.ode_id := 1; x.ode_id := 1; dx_dt.ode_type := 2; x.ode_type := 1;
38	dv_dt.ode_id := 2; v.ode_id := 2; dv_dt.ode_type := 2; v.ode_type := 1;
39	t.obs_id := 1;
40	x.obs_id := 2;
41	v.obs_id := 3;
42	dv_dt.obs_id := 4;
43	v.ode_atol := 1e-8;
44	x.ode_atol := 1e-8;
45	END ode_init;
46
47	METHOD on_load;
48	RUN reset; RUN values;
49	RUN ode_init;
50	END on_load;
51
52	METHOD self_test;
53	(* assumes integration up to t = (20/9.8){s}; *)
54	ASSERT abs(x - 0 {m}) < 1e-5 {m};
55	ASSERT abs(v +10 {m/s}) < 1e-5 {m/s};
56	ASSERT abs(dv_dt + g) < 1e-10 {m/s^2};
57	END self_test;
58
59	END newton;