differential-equations-derive 0.2.0

Derives proc macros for the differential-equations crate
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255

use differential_equations::traits::State as StateTrait;
use differential_equations_derive::State;
use nalgebra::{Matrix2, Vector2, Vector3};
use num_complex::Complex;

// Test helper function to verify basic State trait functionality
fn test_state_basics<S: StateTrait<f64>>(state: &mut S, expected_len: usize) {
    // Test length
    assert_eq!(state.len(), expected_len);

    // Test get/set for all elements
    for i in 0..expected_len {
        let original = state.get_component(i);
        state.set_component(i, 42.0);
        assert_eq!(state.get_component(i), 42.0);
        state.set_component(i, original); // Restore
    }

    // Test bulk map update
    state.map_components_mut(|i, val| {
        *val = i as f64 + 1.0;
    });
    for i in 0..expected_len {
        assert_eq!(state.get_component(i), i as f64 + 1.0);
    }
}

#[test]
fn test_single_field_only() {
    #[derive(State, PartialEq)]
    struct SingleField<T> {
        x: T,
    }

    let mut state = SingleField { x: 1.0 };
    test_state_basics(&mut state, 1);

    // Test arithmetic operations
    let other = SingleField { x: 2.0 };
    let sum = state + other;
    assert_eq!(sum.x, 3.0);

    let difference = sum - SingleField { x: 1.0 };
    assert_eq!(difference.x, 2.0);

    let scaled = difference * 3.0;
    assert_eq!(scaled.x, 6.0);

    let divided = scaled / 2.0;
    assert_eq!(divided.x, 3.0);

    // Test zeros
    let zero = SingleField::<f64>::zeros();
    assert_eq!(zero.x, 0.0);
}

#[test]
fn test_multiple_single_fields() {
    #[derive(State)]
    struct MultipleFields<T> {
        x: T,
        y: T,
        z: T,
    }

    let mut state = MultipleFields {
        x: 1.0,
        y: 2.0,
        z: 3.0,
    };
    test_state_basics(&mut state, 3);

    // Test specific indexing
    assert_eq!(state.get_component(0), 1.0);
    assert_eq!(state.get_component(1), 2.0);
    assert_eq!(state.get_component(2), 3.0);

    // Test arithmetic
    let other = MultipleFields {
        x: 1.0,
        y: 1.0,
        z: 1.0,
    };
    let sum = state + other;
    assert_eq!(sum.x, 2.0);
    assert_eq!(sum.y, 3.0);
    assert_eq!(sum.z, 4.0);
}

#[test]
fn test_non_generic_named_state() {
    #[derive(State, PartialEq)]
    struct ConcreteState {
        x: f64,
        y: f64,
        velocity: [f64; 2],
    }

    let mut state = ConcreteState {
        x: 1.0,
        y: 2.0,
        velocity: [3.0, 4.0],
    };
    test_state_basics(&mut state, 4);

    let other = ConcreteState {
        x: 0.5,
        y: 1.5,
        velocity: [2.0, 3.0],
    };
    let sum = state + other;
    assert_eq!(sum.x, 1.5);
    assert_eq!(sum.y, 3.5);
    assert_eq!(sum.velocity, [5.0, 7.0]);

    let scaled = sum * 2.0;
    assert_eq!(scaled.x, 3.0);
    assert_eq!(scaled.y, 7.0);
    assert_eq!(scaled.velocity, [10.0, 14.0]);

    let zero = ConcreteState::zeros();
    assert_eq!(zero.x, 0.0);
    assert_eq!(zero.y, 0.0);
    assert_eq!(zero.velocity, [0.0, 0.0]);
}

#[test]
fn test_non_generic_tuple_state() {
    #[derive(State, PartialEq)]
    struct ConcreteTuple(f64, [f64; 2]);

    let mut state = ConcreteTuple(1.0, [2.0, 3.0]);
    test_state_basics(&mut state, 3);

    let difference = state - ConcreteTuple(1.0, [1.0, 1.0]);
    assert_eq!(difference.0, 0.0);
    assert_eq!(difference.1, [1.0, 2.0]);
}

#[test]
fn test_array_fields_only() {
    #[derive(State)]
    struct ArrayFields<T> {
        small_array: [T; 2],
        large_array: [T; 5],
    }

    let mut state = ArrayFields {
        small_array: [1.0, 2.0],
        large_array: [3.0, 4.0, 5.0, 6.0, 7.0],
    };
    test_state_basics(&mut state, 7); // 2 + 5 = 7 elements

    // Test array element access
    assert_eq!(state.get_component(0), 1.0); // small_array[0]
    assert_eq!(state.get_component(1), 2.0); // small_array[1]
    assert_eq!(state.get_component(2), 3.0); // large_array[0]
    assert_eq!(state.get_component(6), 7.0); // large_array[4]

    // Test arithmetic with arrays
    let other = ArrayFields {
        small_array: [0.5, 0.5],
        large_array: [1.0, 1.0, 1.0, 1.0, 1.0],
    };
    let sum = state + other;
    assert_eq!(sum.small_array[0], 1.5);
    assert_eq!(sum.large_array[2], 6.0);
}

#[test]
fn test_nalgebra_fields_only() {
    #[derive(State)]
    struct NalgebraFields<T> {
        vec2: Vector2<T>,
        vec3: Vector3<T>,
        mat2: Matrix2<T>,
    }

    let mut state = NalgebraFields {
        vec2: Vector2::new(1.0, 2.0),
        vec3: Vector3::new(3.0, 4.0, 5.0),
        mat2: Matrix2::new(6.0, 7.0, 8.0, 9.0),
    };
    test_state_basics(&mut state, 9); // 2 + 3 + 4 = 9 elements

    // Test matrix element access (row-major order)
    assert_eq!(state.get_component(0), 1.0); // vec2[0]
    assert_eq!(state.get_component(1), 2.0); // vec2[1]
    assert_eq!(state.get_component(2), 3.0); // vec3[0]
    assert_eq!(state.get_component(4), 5.0); // vec3[2]
    assert_eq!(state.get_component(5), 6.0); // mat2[(0,0)]
    assert_eq!(state.get_component(6), 7.0); // mat2[(0,1)]
    assert_eq!(state.get_component(7), 8.0); // mat2[(1,0)]
    assert_eq!(state.get_component(8), 9.0); // mat2[(1,1)]
}

#[test]
fn test_complex_fields_only() {
    #[derive(State)]
    struct ComplexFields<T> {
        z1: Complex<T>,
        z2: Complex<T>,
    }

    let mut state = ComplexFields {
        z1: Complex::new(1.0, 2.0),
        z2: Complex::new(3.0, 4.0),
    };
    test_state_basics(&mut state, 4); // 2 complex = 4 real elements

    // Test complex element access
    assert_eq!(state.get_component(0), 1.0); // z1.re
    assert_eq!(state.get_component(1), 2.0); // z1.im
    assert_eq!(state.get_component(2), 3.0); // z2.re
    assert_eq!(state.get_component(3), 4.0); // z2.im

    // Test complex arithmetic
    let other = ComplexFields {
        z1: Complex::new(0.5, 0.5),
        z2: Complex::new(1.0, 1.0),
    };
    let sum = state + other;
    assert_eq!(sum.z1.re, 1.5);
    assert_eq!(sum.z1.im, 2.5);
    assert_eq!(sum.z2.re, 4.0);
    assert_eq!(sum.z2.im, 5.0);
}

#[test]
fn test_mixed_field_types() {
    #[derive(State)]
    struct MixedState<T> {
        scalar: T,
        array: [T; 3],
        vector: Vector2<T>,
        complex: Complex<T>,
    }

    let mut state = MixedState {
        scalar: 1.0,
        array: [2.0, 3.0, 4.0],
        vector: Vector2::new(5.0, 6.0),
        complex: Complex::new(7.0, 8.0),
    };
    test_state_basics(&mut state, 8); // 1 + 3 + 2 + 2 = 8 elements

    // Test mixed element access
    assert_eq!(state.get_component(0), 1.0); // scalar
    assert_eq!(state.get_component(1), 2.0); // array[0]
    assert_eq!(state.get_component(3), 4.0); // array[2]
    assert_eq!(state.get_component(4), 5.0); // vector[0]
    assert_eq!(state.get_component(5), 6.0); // vector[1]
    assert_eq!(state.get_component(6), 7.0); // complex.re
    assert_eq!(state.get_component(7), 8.0); // complex.im
}