differential_equations/methods/erk/fixed/
mod.rs

1//! Runge-Kutta solvers with fixed step-size.
2
3mod delay;
4mod ordinary;
5mod stochastic;
6
7use crate::{
8    methods::{ExplicitRungeKutta, Fixed},
9    tableau::ButcherTableau,
10    traits::{Real, State},
11};
12
13// Macro for fixed step constructors
14macro_rules! impl_erk_fixed_step_constructor {
15    ($method_name:ident, $fsal_val:expr, $order_val:expr, $s_val:expr, $doc:expr) => {
16        impl<E, T: Real, Y: State<T>>
17            ExplicitRungeKutta<E, Fixed, T, Y, $order_val, $s_val, $s_val>
18        {
19            #[doc = $doc]
20            pub fn $method_name(h0: T) -> Self {
21                let tableau = ButcherTableau::$method_name();
22                let c = tableau.c;
23                let a = tableau.a;
24                let b = tableau.b;
25                let fsal = $fsal_val;
26
27                ExplicitRungeKutta {
28                    h0,
29                    c,
30                    a,
31                    b,
32                    fsal,
33                    ..Default::default()
34                }
35            }
36        }
37    };
38}
39
40// Fixed step methods (S = I, no embedded error estimation, cubic Hermite interpolation)
41impl_erk_fixed_step_constructor!(
42    euler,
43    false,
44    1,
45    1,
46    "Creates an Explicit Euler method (1st order, 1 stage)."
47);
48impl_erk_fixed_step_constructor!(
49    midpoint,
50    false,
51    2,
52    2,
53    "Creates an Explicit Midpoint method (2nd order, 2 stages)."
54);
55impl_erk_fixed_step_constructor!(
56    heun,
57    false,
58    2,
59    2,
60    "Creates an Explicit Heun method (2nd order, 2 stages)."
61);
62impl_erk_fixed_step_constructor!(
63    ralston,
64    false,
65    2,
66    2,
67    "Creates an Explicit Ralston method (2nd order, 2 stages)."
68);
69impl_erk_fixed_step_constructor!(
70    rk4,
71    false,
72    4,
73    4,
74    "Creates the classical 4th order Runge-Kutta method."
75);
76impl_erk_fixed_step_constructor!(
77    three_eighths,
78    false,
79    4,
80    4,
81    "Creates the three-eighths rule 4th order Runge-Kutta method."
82);
differential_equations/methods/erk/fixed/mod.rs

differential_equations/methods/erk/fixed/
mod.rs
