forked from M-Labs/nalgebra
98 lines
3.1 KiB
Rust
98 lines
3.1 KiB
Rust
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#[cfg(test)]
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mod tests {
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//https://github.com/scipy/scipy/blob/c1372d8aa90a73d8a52f135529293ff4edb98fc8/scipy/sparse/linalg/tests/test_matfuncs.py
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#[test]
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fn exp() {
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use nalgebra::{Matrix1, Matrix2, Matrix3};
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{
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let m = Matrix1::new(1.0);
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let f = m.exp();
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assert_eq!(f, Matrix1::new(1_f64.exp()));
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}
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{
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let m = Matrix2::new(0.0, 1.0, 0.0, 0.0);
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assert_eq!(m.exp(), Matrix2::new(1.0, 1.0, 0.0, 1.0));
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}
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{
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let a: f64 = 1.0;
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let b: f64 = 2.0;
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let c: f64 = 3.0;
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let d: f64 = 4.0;
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let m = Matrix2::new(a, b, c, d);
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let delta = ((a - d).powf(2.0) + 4.0 * b * c).sqrt();
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let delta_2 = delta / 2.0;
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let ad_2 = (a + d) / 2.0;
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let m11 = ad_2.exp() * (delta * delta_2.cosh() + (a - d) * delta_2.sinh());
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let m12 = 2.0 * b * ad_2.exp() * delta_2.sinh();
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let m21 = 2.0 * c * ad_2.exp() * delta_2.sinh();
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let m22 = ad_2.exp() * (delta * delta_2.cosh() + (d - a) * delta_2.sinh());
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let f = Matrix2::new(m11, m12, m21, m22) / delta;
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assert!((f - m.exp()).iter().all(|v| v.abs() <= 0.00005));
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}
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{
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// https://mathworld.wolfram.com/MatrixExponential.html
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use rand::{
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distributions::{Distribution, Uniform},
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thread_rng,
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};
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let mut rng = thread_rng();
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let dist = Uniform::new(-10.0, 10.0);
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loop {
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let a: f64 = dist.sample(&mut rng);
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let b: f64 = dist.sample(&mut rng);
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let c: f64 = dist.sample(&mut rng);
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let d: f64 = dist.sample(&mut rng);
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let m = Matrix2::new(a, b, c, d);
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let delta_sq = (a - d).powf(2.0) + 4.0 * b * c;
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if delta_sq < 0.0 {
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continue;
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}
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let delta = delta_sq.sqrt();
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let delta_2 = delta / 2.0;
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let ad_2 = (a + d) / 2.0;
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let m11 = ad_2.exp() * (delta * delta_2.cosh() + (a - d) * delta_2.sinh());
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let m12 = 2.0 * b * ad_2.exp() * delta_2.sinh();
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let m21 = 2.0 * c * ad_2.exp() * delta_2.sinh();
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let m22 = ad_2.exp() * (delta * delta_2.cosh() + (d - a) * delta_2.sinh());
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let f = Matrix2::new(m11, m12, m21, m22) / delta;
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println!("a: {}", m);
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assert!((f - m.exp()).iter().all(|v| v.abs() <= 0.00005));
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break;
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}
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}
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{
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let m = Matrix3::new(1.0, 3.0, 0.0, 0.0, 1.0, 5.0, 0.0, 0.0, 2.0);
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let e1 = 1.0_f64.exp();
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let e2 = 2.0_f64.exp();
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let f = Matrix3::new(
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e1,
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3.0 * e1,
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15.0 * (e2 - 2.0 * e1),
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0.0,
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e1,
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5.0 * (e2 - e1),
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0.0,
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0.0,
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e2,
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);
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assert!((f - m.exp()).iter().all(|v| v.abs() <= 0.00005));
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}
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}
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}
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