162bed2aa2
* test: run tests also in wasm targets * fix: install rand with wasm-bindgen por wasm targets * fix: use actual usize size to access buffer. * fix: do not run functions that create files in wasm. * test: do not run in wasm test that panics. Co-authored-by: Luis Moreno <morenol@users.noreply.github.com>
744 lines
22 KiB
Rust
744 lines
22 KiB
Rust
//! # SVD Decomposition
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//!
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//! Any _m_ by _n_ matrix \\(A\\) can be factored into:
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//!
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//! \\[A = U \Sigma V^T\\]
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//!
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//! Where columns of \\(U\\) are eigenvectors of \\(AA^T\\) (left-singular vectors of _A_),
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//! \\(V\\) are eigenvectors of \\(A^TA\\) (right-singular vectors of _A_),
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//! and the diagonal values in the \\(\Sigma\\) matrix are known as the singular values of the original matrix.
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//!
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//! Example:
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//! ```
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//! use smartcore::linalg::naive::dense_matrix::*;
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//! use smartcore::linalg::svd::*;
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//!
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//! let A = DenseMatrix::from_2d_array(&[
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//! &[0.9, 0.4, 0.7],
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//! &[0.4, 0.5, 0.3],
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//! &[0.7, 0.3, 0.8]
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//! ]);
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//!
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//! let svd = A.svd().unwrap();
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//! let u: DenseMatrix<f64> = svd.U;
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//! let v: DenseMatrix<f64> = svd.V;
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//! let s: Vec<f64> = svd.s;
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//! ```
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//!
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//! ## References:
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//! * ["Linear Algebra and Its Applications", Gilbert Strang, 5th ed., 6.3 Singular Value Decomposition](https://www.academia.edu/32459792/_Strang_G_Linear_algebra_and_its_applications_4_5881001_PDF)
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//! * ["Numerical Recipes: The Art of Scientific Computing", Press W.H., Teukolsky S.A., Vetterling W.T, Flannery B.P, 3rd ed., 2.6 Singular Value Decomposition](http://numerical.recipes/)
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//!
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//! <script src="https://polyfill.io/v3/polyfill.min.js?features=es6"></script>
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//! <script id="MathJax-script" async src="https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js"></script>
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#![allow(non_snake_case)]
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use crate::error::Failed;
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use crate::linalg::BaseMatrix;
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use crate::math::num::RealNumber;
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use std::fmt::Debug;
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/// Results of SVD decomposition
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#[derive(Debug, Clone)]
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pub struct SVD<T: RealNumber, M: SVDDecomposableMatrix<T>> {
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/// Left-singular vectors of _A_
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pub U: M,
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/// Right-singular vectors of _A_
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pub V: M,
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/// Singular values of the original matrix
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pub s: Vec<T>,
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full: bool,
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m: usize,
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n: usize,
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tol: T,
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}
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impl<T: RealNumber, M: SVDDecomposableMatrix<T>> SVD<T, M> {
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/// Diagonal matrix with singular values
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pub fn S(&self) -> M {
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let mut s = M::zeros(self.U.shape().1, self.V.shape().0);
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for i in 0..self.s.len() {
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s.set(i, i, self.s[i]);
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}
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s
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}
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}
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/// Trait that implements SVD decomposition routine for any matrix.
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pub trait SVDDecomposableMatrix<T: RealNumber>: BaseMatrix<T> {
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/// Solves Ax = b. Overrides original matrix in the process.
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fn svd_solve_mut(self, b: Self) -> Result<Self, Failed> {
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self.svd_mut().and_then(|svd| svd.solve(b))
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}
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/// Solves Ax = b
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fn svd_solve(&self, b: Self) -> Result<Self, Failed> {
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self.svd().and_then(|svd| svd.solve(b))
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}
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/// Compute the SVD decomposition of a matrix.
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fn svd(&self) -> Result<SVD<T, Self>, Failed> {
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self.clone().svd_mut()
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}
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/// Compute the SVD decomposition of a matrix. The input matrix
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/// will be used for factorization.
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fn svd_mut(self) -> Result<SVD<T, Self>, Failed> {
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let mut U = self;
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let (m, n) = U.shape();
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let (mut l, mut nm) = (0usize, 0usize);
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let (mut anorm, mut g, mut scale) = (T::zero(), T::zero(), T::zero());
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let mut v = Self::zeros(n, n);
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let mut w = vec![T::zero(); n];
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let mut rv1 = vec![T::zero(); n];
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for i in 0..n {
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l = i + 2;
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rv1[i] = scale * g;
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g = T::zero();
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let mut s = T::zero();
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scale = T::zero();
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if i < m {
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for k in i..m {
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scale += U.get(k, i).abs();
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}
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if scale.abs() > T::epsilon() {
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for k in i..m {
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U.div_element_mut(k, i, scale);
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s += U.get(k, i) * U.get(k, i);
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}
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let mut f = U.get(i, i);
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g = -s.sqrt().copysign(f);
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let h = f * g - s;
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U.set(i, i, f - g);
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for j in l - 1..n {
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s = T::zero();
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for k in i..m {
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s += U.get(k, i) * U.get(k, j);
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}
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f = s / h;
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for k in i..m {
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U.add_element_mut(k, j, f * U.get(k, i));
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}
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}
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for k in i..m {
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U.mul_element_mut(k, i, scale);
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}
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}
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}
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w[i] = scale * g;
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g = T::zero();
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let mut s = T::zero();
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scale = T::zero();
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if i < m && i + 1 != n {
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for k in l - 1..n {
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scale += U.get(i, k).abs();
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}
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if scale.abs() > T::epsilon() {
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for k in l - 1..n {
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U.div_element_mut(i, k, scale);
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s += U.get(i, k) * U.get(i, k);
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}
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let f = U.get(i, l - 1);
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g = -s.sqrt().copysign(f);
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let h = f * g - s;
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U.set(i, l - 1, f - g);
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for (k, rv1_k) in rv1.iter_mut().enumerate().take(n).skip(l - 1) {
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*rv1_k = U.get(i, k) / h;
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}
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for j in l - 1..m {
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s = T::zero();
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for k in l - 1..n {
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s += U.get(j, k) * U.get(i, k);
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}
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for (k, rv1_k) in rv1.iter().enumerate().take(n).skip(l - 1) {
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U.add_element_mut(j, k, s * (*rv1_k));
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}
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}
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for k in l - 1..n {
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U.mul_element_mut(i, k, scale);
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}
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}
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}
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anorm = T::max(anorm, w[i].abs() + rv1[i].abs());
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}
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for i in (0..n).rev() {
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if i < n - 1 {
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if g != T::zero() {
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for j in l..n {
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v.set(j, i, (U.get(i, j) / U.get(i, l)) / g);
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}
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for j in l..n {
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let mut s = T::zero();
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for k in l..n {
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s += U.get(i, k) * v.get(k, j);
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}
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for k in l..n {
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v.add_element_mut(k, j, s * v.get(k, i));
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}
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}
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}
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for j in l..n {
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v.set(i, j, T::zero());
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v.set(j, i, T::zero());
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}
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}
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v.set(i, i, T::one());
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g = rv1[i];
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l = i;
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}
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for i in (0..usize::min(m, n)).rev() {
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l = i + 1;
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g = w[i];
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for j in l..n {
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U.set(i, j, T::zero());
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}
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if g.abs() > T::epsilon() {
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g = T::one() / g;
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for j in l..n {
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let mut s = T::zero();
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for k in l..m {
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s += U.get(k, i) * U.get(k, j);
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}
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let f = (s / U.get(i, i)) * g;
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for k in i..m {
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U.add_element_mut(k, j, f * U.get(k, i));
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}
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}
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for j in i..m {
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U.mul_element_mut(j, i, g);
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}
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} else {
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for j in i..m {
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U.set(j, i, T::zero());
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}
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}
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U.add_element_mut(i, i, T::one());
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}
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for k in (0..n).rev() {
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for iteration in 0..30 {
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let mut flag = true;
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l = k;
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while l != 0 {
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if l == 0 || rv1[l].abs() <= T::epsilon() * anorm {
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flag = false;
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break;
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}
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nm = l - 1;
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if w[nm].abs() <= T::epsilon() * anorm {
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break;
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}
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l -= 1;
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}
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if flag {
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let mut c = T::zero();
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let mut s = T::one();
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for i in l..k + 1 {
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let f = s * rv1[i];
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rv1[i] = c * rv1[i];
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if f.abs() <= T::epsilon() * anorm {
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break;
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}
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g = w[i];
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let mut h = f.hypot(g);
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w[i] = h;
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h = T::one() / h;
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c = g * h;
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s = -f * h;
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for j in 0..m {
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let y = U.get(j, nm);
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let z = U.get(j, i);
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U.set(j, nm, y * c + z * s);
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U.set(j, i, z * c - y * s);
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}
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}
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}
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let z = w[k];
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if l == k {
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if z < T::zero() {
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w[k] = -z;
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for j in 0..n {
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v.set(j, k, -v.get(j, k));
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}
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}
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break;
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}
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if iteration == 29 {
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panic!("no convergence in 30 iterations");
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}
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let mut x = w[l];
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nm = k - 1;
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let mut y = w[nm];
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g = rv1[nm];
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let mut h = rv1[k];
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let mut f = ((y - z) * (y + z) + (g - h) * (g + h)) / (T::two() * h * y);
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g = f.hypot(T::one());
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f = ((x - z) * (x + z) + h * ((y / (f + g.copysign(f))) - h)) / x;
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let mut c = T::one();
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let mut s = T::one();
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for j in l..=nm {
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let i = j + 1;
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g = rv1[i];
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y = w[i];
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h = s * g;
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g = c * g;
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let mut z = f.hypot(h);
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rv1[j] = z;
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c = f / z;
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s = h / z;
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f = x * c + g * s;
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g = g * c - x * s;
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h = y * s;
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y *= c;
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for jj in 0..n {
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x = v.get(jj, j);
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z = v.get(jj, i);
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v.set(jj, j, x * c + z * s);
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v.set(jj, i, z * c - x * s);
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}
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z = f.hypot(h);
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w[j] = z;
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if z.abs() > T::epsilon() {
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z = T::one() / z;
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c = f * z;
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s = h * z;
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}
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f = c * g + s * y;
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x = c * y - s * g;
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for jj in 0..m {
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y = U.get(jj, j);
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z = U.get(jj, i);
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U.set(jj, j, y * c + z * s);
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U.set(jj, i, z * c - y * s);
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}
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}
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rv1[l] = T::zero();
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rv1[k] = f;
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w[k] = x;
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}
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}
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let mut inc = 1usize;
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let mut su = vec![T::zero(); m];
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let mut sv = vec![T::zero(); n];
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loop {
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inc *= 3;
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inc += 1;
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if inc > n {
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break;
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}
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}
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loop {
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inc /= 3;
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for i in inc..n {
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let sw = w[i];
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for (k, su_k) in su.iter_mut().enumerate().take(m) {
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*su_k = U.get(k, i);
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}
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for (k, sv_k) in sv.iter_mut().enumerate().take(n) {
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*sv_k = v.get(k, i);
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}
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let mut j = i;
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while w[j - inc] < sw {
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w[j] = w[j - inc];
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for k in 0..m {
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U.set(k, j, U.get(k, j - inc));
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}
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for k in 0..n {
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v.set(k, j, v.get(k, j - inc));
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}
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j -= inc;
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if j < inc {
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break;
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}
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}
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w[j] = sw;
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for (k, su_k) in su.iter().enumerate().take(m) {
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U.set(k, j, *su_k);
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}
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for (k, sv_k) in sv.iter().enumerate().take(n) {
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v.set(k, j, *sv_k);
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}
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}
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if inc <= 1 {
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break;
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}
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}
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for k in 0..n {
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let mut s = 0.;
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for i in 0..m {
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if U.get(i, k) < T::zero() {
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s += 1.;
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}
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}
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for j in 0..n {
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if v.get(j, k) < T::zero() {
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s += 1.;
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}
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}
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if s > (m + n) as f64 / 2. {
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for i in 0..m {
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U.set(i, k, -U.get(i, k));
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}
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for j in 0..n {
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v.set(j, k, -v.get(j, k));
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}
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}
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}
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Ok(SVD::new(U, v, w))
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}
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}
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impl<T: RealNumber, M: SVDDecomposableMatrix<T>> SVD<T, M> {
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pub(crate) fn new(U: M, V: M, s: Vec<T>) -> SVD<T, M> {
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let m = U.shape().0;
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let n = V.shape().0;
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let full = s.len() == m.min(n);
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let tol = T::half() * (T::from(m + n).unwrap() + T::one()).sqrt() * s[0] * T::epsilon();
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SVD {
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U,
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V,
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s,
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full,
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m,
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n,
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tol,
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}
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}
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pub(crate) fn solve(&self, mut b: M) -> Result<M, Failed> {
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let p = b.shape().1;
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if self.U.shape().0 != b.shape().0 {
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panic!(
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"Dimensions do not agree. U.nrows should equal b.nrows but is {}, {}",
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self.U.shape().0,
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b.shape().0
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);
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}
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for k in 0..p {
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let mut tmp = vec![T::zero(); self.n];
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for (j, tmp_j) in tmp.iter_mut().enumerate().take(self.n) {
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let mut r = T::zero();
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if self.s[j] > self.tol {
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for i in 0..self.m {
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r += self.U.get(i, j) * b.get(i, k);
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}
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r /= self.s[j];
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}
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*tmp_j = r;
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}
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for j in 0..self.n {
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let mut r = T::zero();
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for (jj, tmp_jj) in tmp.iter().enumerate().take(self.n) {
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r += self.V.get(j, jj) * (*tmp_jj);
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}
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b.set(j, k, r);
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}
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}
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Ok(b)
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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use crate::linalg::naive::dense_matrix::DenseMatrix;
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#[cfg_attr(target_arch = "wasm32", wasm_bindgen_test::wasm_bindgen_test)]
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#[test]
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fn decompose_symmetric() {
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let A = DenseMatrix::from_2d_array(&[
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&[0.9000, 0.4000, 0.7000],
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&[0.4000, 0.5000, 0.3000],
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&[0.7000, 0.3000, 0.8000],
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]);
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let s: Vec<f64> = vec![1.7498382, 0.3165784, 0.1335834];
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let U = DenseMatrix::from_2d_array(&[
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&[0.6881997, -0.07121225, 0.7220180],
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&[0.3700456, 0.89044952, -0.2648886],
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&[0.6240573, -0.44947578, -0.639158],
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]);
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let V = DenseMatrix::from_2d_array(&[
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&[0.6881997, -0.07121225, 0.7220180],
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&[0.3700456, 0.89044952, -0.2648886],
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&[0.6240573, -0.44947578, -0.6391588],
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]);
|
|
|
|
let svd = A.svd().unwrap();
|
|
|
|
assert!(V.abs().approximate_eq(&svd.V.abs(), 1e-4));
|
|
assert!(U.abs().approximate_eq(&svd.U.abs(), 1e-4));
|
|
for i in 0..s.len() {
|
|
assert!((s[i] - svd.s[i]).abs() < 1e-4);
|
|
}
|
|
}
|
|
#[cfg_attr(target_arch = "wasm32", wasm_bindgen_test::wasm_bindgen_test)]
|
|
#[test]
|
|
fn decompose_asymmetric() {
|
|
let A = DenseMatrix::from_2d_array(&[
|
|
&[
|
|
1.19720880,
|
|
-1.8391378,
|
|
0.3019585,
|
|
-1.1165701,
|
|
-1.7210814,
|
|
0.4918882,
|
|
-0.04247433,
|
|
],
|
|
&[
|
|
0.06605075,
|
|
1.0315583,
|
|
0.8294362,
|
|
-0.3646043,
|
|
-1.6038017,
|
|
-0.9188110,
|
|
-0.63760340,
|
|
],
|
|
&[
|
|
-1.02637715,
|
|
1.0747931,
|
|
-0.8089055,
|
|
-0.4726863,
|
|
-0.2064826,
|
|
-0.3325532,
|
|
0.17966051,
|
|
],
|
|
&[
|
|
-1.45817729,
|
|
-0.8942353,
|
|
0.3459245,
|
|
1.5068363,
|
|
-2.0180708,
|
|
-0.3696350,
|
|
-1.19575563,
|
|
],
|
|
&[
|
|
-0.07318103,
|
|
-0.2783787,
|
|
1.2237598,
|
|
0.1995332,
|
|
0.2545336,
|
|
-0.1392502,
|
|
-1.88207227,
|
|
],
|
|
&[
|
|
0.88248425, -0.9360321, 0.1393172, 0.1393281, -0.3277873, -0.5553013, 1.63805985,
|
|
],
|
|
&[
|
|
0.12641406,
|
|
-0.8710055,
|
|
-0.2712301,
|
|
0.2296515,
|
|
1.1781535,
|
|
-0.2158704,
|
|
-0.27529472,
|
|
],
|
|
]);
|
|
|
|
let s: Vec<f64> = vec![
|
|
3.8589375, 3.4396766, 2.6487176, 2.2317399, 1.5165054, 0.8109055, 0.2706515,
|
|
];
|
|
|
|
let U = DenseMatrix::from_2d_array(&[
|
|
&[
|
|
-0.3082776,
|
|
0.77676231,
|
|
0.01330514,
|
|
0.23231424,
|
|
-0.47682758,
|
|
0.13927109,
|
|
0.02640713,
|
|
],
|
|
&[
|
|
-0.4013477,
|
|
-0.09112050,
|
|
0.48754440,
|
|
0.47371793,
|
|
0.40636608,
|
|
0.24600706,
|
|
-0.37796295,
|
|
],
|
|
&[
|
|
0.0599719,
|
|
-0.31406586,
|
|
0.45428229,
|
|
-0.08071283,
|
|
-0.38432597,
|
|
0.57320261,
|
|
0.45673993,
|
|
],
|
|
&[
|
|
-0.7694214,
|
|
-0.12681435,
|
|
-0.05536793,
|
|
-0.62189972,
|
|
-0.02075522,
|
|
-0.01724911,
|
|
-0.03681864,
|
|
],
|
|
&[
|
|
-0.3319069,
|
|
-0.17984404,
|
|
-0.54466777,
|
|
0.45335157,
|
|
0.19377726,
|
|
0.12333423,
|
|
0.55003852,
|
|
],
|
|
&[
|
|
0.1259351,
|
|
0.49087824,
|
|
0.16349687,
|
|
-0.32080176,
|
|
0.64828744,
|
|
0.20643772,
|
|
0.38812467,
|
|
],
|
|
&[
|
|
0.1491884,
|
|
0.01768604,
|
|
-0.47884363,
|
|
-0.14108924,
|
|
0.03922507,
|
|
0.73034065,
|
|
-0.43965505,
|
|
],
|
|
]);
|
|
|
|
let V = DenseMatrix::from_2d_array(&[
|
|
&[
|
|
-0.2122609,
|
|
-0.54650056,
|
|
0.08071332,
|
|
-0.43239135,
|
|
-0.2925067,
|
|
0.1414550,
|
|
0.59769207,
|
|
],
|
|
&[
|
|
-0.1943605,
|
|
0.63132116,
|
|
-0.54059857,
|
|
-0.37089970,
|
|
-0.1363031,
|
|
0.2892641,
|
|
0.17774114,
|
|
],
|
|
&[
|
|
0.3031265,
|
|
-0.06182488,
|
|
0.18579097,
|
|
-0.38606409,
|
|
-0.5364911,
|
|
0.2983466,
|
|
-0.58642548,
|
|
],
|
|
&[
|
|
0.1844063, 0.24425278, 0.25923756, 0.59043765, -0.4435443, 0.3959057, 0.37019098,
|
|
],
|
|
&[
|
|
-0.7164205,
|
|
0.30694911,
|
|
0.58264743,
|
|
-0.07458095,
|
|
-0.1142140,
|
|
-0.1311972,
|
|
-0.13124764,
|
|
],
|
|
&[
|
|
-0.1103067,
|
|
-0.10633600,
|
|
0.18257905,
|
|
-0.03638501,
|
|
0.5722925,
|
|
0.7784398,
|
|
-0.09153611,
|
|
],
|
|
&[
|
|
-0.5156083,
|
|
-0.36573746,
|
|
-0.47613340,
|
|
0.41342817,
|
|
-0.2659765,
|
|
0.1654796,
|
|
-0.32346758,
|
|
],
|
|
]);
|
|
|
|
let svd = A.svd().unwrap();
|
|
|
|
assert!(V.abs().approximate_eq(&svd.V.abs(), 1e-4));
|
|
assert!(U.abs().approximate_eq(&svd.U.abs(), 1e-4));
|
|
for i in 0..s.len() {
|
|
assert!((s[i] - svd.s[i]).abs() < 1e-4);
|
|
}
|
|
}
|
|
#[cfg_attr(target_arch = "wasm32", wasm_bindgen_test::wasm_bindgen_test)]
|
|
#[test]
|
|
fn solve() {
|
|
let a = DenseMatrix::from_2d_array(&[&[0.9, 0.4, 0.7], &[0.4, 0.5, 0.3], &[0.7, 0.3, 0.8]]);
|
|
let b = DenseMatrix::from_2d_array(&[&[0.5, 0.2], &[0.5, 0.8], &[0.5, 0.3]]);
|
|
let expected_w =
|
|
DenseMatrix::from_2d_array(&[&[-0.20, -1.28], &[0.87, 2.22], &[0.47, 0.66]]);
|
|
let w = a.svd_solve_mut(b).unwrap();
|
|
assert!(w.approximate_eq(&expected_w, 1e-2));
|
|
}
|
|
|
|
#[cfg_attr(target_arch = "wasm32", wasm_bindgen_test::wasm_bindgen_test)]
|
|
#[test]
|
|
fn decompose_restore() {
|
|
let a = DenseMatrix::from_2d_array(&[&[1.0, 2.0, 3.0, 4.0], &[5.0, 6.0, 7.0, 8.0]]);
|
|
let svd = a.svd().unwrap();
|
|
let u: &DenseMatrix<f32> = &svd.U; //U
|
|
let v: &DenseMatrix<f32> = &svd.V; // V
|
|
let s: &DenseMatrix<f32> = &svd.S(); // Sigma
|
|
|
|
let a_hat = u.matmul(s).matmul(&v.transpose());
|
|
|
|
for (a, a_hat) in a.iter().zip(a_hat.iter()) {
|
|
assert!((a - a_hat).abs() < 1e-3)
|
|
}
|
|
}
|
|
}
|