26 lines
715 B
Rust
26 lines
715 B
Rust
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use crate::{Matrix3, SVD, U3};
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use simba::scalar::RealField;
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// For the 3x3 case, on the GPU, it is much more efficient to compute the SVD
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// using an eigendecomposition followed by a QR decomposition.
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pub fn svd3<T: RealField>(
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m: &Matrix3<T>,
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compute_u: bool,
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compute_v: bool,
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eps: T,
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niter: usize,
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) -> Option<SVD<T, U3, U3>> {
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let s = m.tr_mul(&m);
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let v = s.try_symmetric_eigen(eps, niter)?.eigenvectors;
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let b = m * &v;
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let qr = b.qr();
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let singular_values = qr.diag_internal().map(|e| e.abs());
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Some(SVD {
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u: if compute_u { Some(qr.q()) } else { None },
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singular_values,
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v_t: if compute_v { Some(v.transpose()) } else { None },
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})
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}
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