1use crate::math::{
2 Derivative, Differentiate, Quantity, Scalar, Tensor, TensorVec,
3 integrate::{
4 ExplicitDaeVariableStepExplicit, ExplicitDaeVariableStepFirstSameAsLast, IntegrationError,
5 Times, ode::explicit::variable_step::dormand_prince::*,
6 },
7};
8use std::ops::{Mul, Sub};
9
10impl<Y, Z, U, V, W, T> ExplicitDaeVariableStepExplicit<Y, Z, U, V, W, T> for DormandPrince
11where
12 Self: ExplicitDaeVariableStepFirstSameAsLast<Y, Z, U, V, W, T>,
13 Y: Differentiate<T> + Tensor,
14 Z: PartialEq + Tensor,
15 Derivative<Y, T>: Mul<Quantity<T>, Output = Y>,
16 U: TensorVec<Item = Y>,
17 V: TensorVec<Item = Z>,
18 W: TensorVec<Item = Derivative<Y, T>>,
19 for<'a> &'a Y: Mul<Scalar, Output = Y> + Sub<&'a Y, Output = Y>,
20 for<'a> &'a Derivative<Y, T>:
21 Mul<Scalar, Output = Derivative<Y, T>> + Mul<Quantity<T>, Output = Y>,
22{
23 fn slopes_solve(
24 mut evolution: impl FnMut(Quantity<T>, &Y, &Z) -> Result<Derivative<Y, T>, String>,
25 mut solution: impl FnMut(Quantity<T>, &Y, &Z) -> Result<Z, String>,
26 y: &Y,
27 z: &Z,
28 t: Quantity<T>,
29 dt: Quantity<T>,
30 k: &mut [Derivative<Y, T>],
31 y_trial: &mut Y,
32 z_trial: &mut Z,
33 ) -> Result<(), String> {
34 *y_trial = &k[0] * (0.2 * dt) + y;
35 *z_trial = solution(t + 0.2 * dt, y_trial, z)?;
36 k[1] = evolution(t + 0.2 * dt, y_trial, z_trial)?;
37 *y_trial = &k[0] * (0.075 * dt) + &k[1] * (0.225 * dt) + y;
38 *z_trial = solution(t + 0.3 * dt, y_trial, z_trial)?;
39 k[2] = evolution(t + 0.3 * dt, y_trial, z_trial)?;
40 *y_trial = &k[0] * (C_44_45 * dt) - &k[1] * (C_56_15 * dt) + &k[2] * (C_32_9 * dt) + y;
41 *z_trial = solution(t + 0.8 * dt, y_trial, z_trial)?;
42 k[3] = evolution(t + 0.8 * dt, y_trial, z_trial)?;
43 *y_trial = &k[0] * (C_19372_6561 * dt) - &k[1] * (C_25360_2187 * dt)
44 + &k[2] * (C_64448_6561 * dt)
45 - &k[3] * (C_212_729 * dt)
46 + y;
47 *z_trial = solution(t + C_8_9 * dt, y_trial, z_trial)?;
48 k[4] = evolution(t + C_8_9 * dt, y_trial, z_trial)?;
49 *y_trial = &k[0] * (C_9017_3168 * dt) - &k[1] * (C_355_33 * dt)
50 + &k[2] * (C_46732_5247 * dt)
51 + &k[3] * (C_49_176 * dt)
52 - &k[4] * (C_5103_18656 * dt)
53 + y;
54 *z_trial = solution(t + dt, y_trial, z_trial)?;
55 k[5] = evolution(t + dt, y_trial, z_trial)?;
56 *y_trial = (&k[0] * C_35_384 + &k[2] * C_500_1113 + &k[3] * C_125_192
57 - &k[4] * C_2187_6784
58 + &k[5] * C_11_84)
59 * dt
60 + y;
61 *z_trial = solution(t + dt, y_trial, z_trial)?;
62 Ok(())
63 }
64 fn slopes_solve_and_error(
65 &self,
66 evolution: impl FnMut(Quantity<T>, &Y, &Z) -> Result<Derivative<Y, T>, String>,
67 solution: impl FnMut(Quantity<T>, &Y, &Z) -> Result<Z, String>,
68 y: &Y,
69 z: &Z,
70 t: Quantity<T>,
71 dt: Quantity<T>,
72 k: &mut [Derivative<Y, T>],
73 y_trial: &mut Y,
74 z_trial: &mut Z,
75 ) -> Result<Scalar, String> {
76 self.slopes_solve_and_error_fsal(evolution, solution, y, z, t, dt, k, y_trial, z_trial)
77 }
78 fn step_solve(
79 &self,
80 _: impl FnMut(Quantity<T>, &Y, &Z) -> Result<Derivative<Y, T>, String>,
81 y: &mut Y,
82 z: &mut Z,
83 t: &mut Quantity<T>,
84 y_sol: &mut U,
85 z_sol: &mut V,
86 t_sol: &mut Times<T>,
87 dydt_sol: &mut W,
88 k_sol: &mut Vec<W>,
89 dt: &mut Quantity<T>,
90 k: &mut [Derivative<Y, T>],
91 y_trial: &Y,
92 z_trial: &Z,
93 e: Scalar,
94 ) -> Result<(), String> {
95 self.step_solve_fsal(
96 y, z, t, y_sol, z_sol, t_sol, dydt_sol, k_sol, dt, k, y_trial, z_trial, e,
97 )
98 }
99 #[allow(clippy::too_many_arguments)]
100 fn interpolate_explicit_dae_variable_step(
101 &self,
102 _evolution: impl FnMut(Quantity<T>, &Y, &Z) -> Result<Derivative<Y, T>, String>,
103 mut solution: impl FnMut(Quantity<T>, &Y, &Z) -> Result<Z, String>,
104 time: &Times<T>,
105 tp: &Times<T>,
106 yp: &U,
107 dydtp: &W,
108 k_sol: &[W],
109 zp: &V,
110 ) -> Result<(U, W, V), IntegrationError> {
111 let (y_int, dydt_int) = Self::interpolate_free_dense(time, tp, yp, dydtp, k_sol);
112 let mut z_int = V::new();
113 for (idx, time_k) in time.iter().enumerate() {
114 let i = tp.iter().position(|tp_i| tp_i >= time_k).unwrap();
115 if time_k == &tp[i] {
116 z_int.push(zp[i].clone());
117 } else {
118 z_int.push(solution(*time_k, &y_int[idx], &zp[i - 1])?);
119 }
120 }
121 Ok((y_int, dydt_int, z_int))
122 }
123}
124
125impl<Y, Z, U, V, W, T> ExplicitDaeVariableStepFirstSameAsLast<Y, Z, U, V, W, T> for DormandPrince
126where
127 Y: Differentiate<T> + Tensor,
128 Z: PartialEq + Tensor,
129 Derivative<Y, T>: Mul<Quantity<T>, Output = Y>,
130 U: TensorVec<Item = Y>,
131 V: TensorVec<Item = Z>,
132 W: TensorVec<Item = Derivative<Y, T>>,
133 for<'a> &'a Y: Mul<Scalar, Output = Y> + Sub<&'a Y, Output = Y>,
134 for<'a> &'a Derivative<Y, T>:
135 Mul<Scalar, Output = Derivative<Y, T>> + Mul<Quantity<T>, Output = Y>,
136{
137}