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82 lines
2.0 KiB
Go
82 lines
2.0 KiB
Go
// Copyright ©2017 The Gonum Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package testlapack
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import (
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"testing"
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"golang.org/x/exp/rand"
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"gonum.org/v1/gonum/blas/blas64"
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)
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func TestDlagsy(t *testing.T) {
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const tol = 1e-14
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rnd := rand.New(rand.NewSource(1))
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for _, n := range []int{0, 1, 2, 3, 4, 5, 10, 50} {
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for _, lda := range []int{0, 2*n + 1} {
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if lda == 0 {
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lda = max(1, n)
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}
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// D is the identity matrix I.
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d := make([]float64, n)
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for i := range d {
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d[i] = 1
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}
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// Allocate an n×n symmetric matrix A and fill it with NaNs.
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a := nanSlice(n * lda)
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work := make([]float64, 2*n)
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// Compute A = U * D * Uᵀ where U is a random orthogonal matrix.
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Dlagsy(n, 0, d, a, lda, rnd, work)
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// A should be the identity matrix because
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// A = U * D * Uᵀ = U * I * Uᵀ = U * Uᵀ = I.
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dist := distFromIdentity(n, a, lda)
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if dist > tol {
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t.Errorf("Case n=%v,lda=%v: |A-I|=%v is too large", n, lda, dist)
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}
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}
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}
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}
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func TestDlagge(t *testing.T) {
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const tol = 1e-14
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rnd := rand.New(rand.NewSource(1))
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for _, n := range []int{0, 1, 2, 3, 4, 5, 10, 50} {
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for _, lda := range []int{0, 2*n + 1} {
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if lda == 0 {
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lda = max(1, n)
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}
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d := make([]float64, n)
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for i := range d {
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d[i] = 1
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}
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a := blas64.General{
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Rows: n,
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Cols: n,
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Stride: lda,
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Data: nanSlice(n * lda),
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}
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work := make([]float64, a.Rows+a.Cols)
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Dlagge(a.Rows, a.Cols, 0, 0, d, a.Data, a.Stride, rnd, work)
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if resid := residualOrthogonal(a, false); resid > tol {
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t.Errorf("Case n=%v,lda=%v: unexpected result", n, lda)
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}
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}
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}
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}
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func TestRandomOrthogonal(t *testing.T) {
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const tol = 1e-14
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rnd := rand.New(rand.NewSource(1))
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for n := 1; n <= 20; n++ {
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q := randomOrthogonal(n, rnd)
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if resid := residualOrthogonal(q, false); resid > tol {
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t.Errorf("Case n=%v: Q not orthogonal; resid=%v, want<=%v", n, resid, tol)
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}
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}
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}
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