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// Copyright ©2016 The Gonum Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package testlapack
import (
"testing"
"golang.org/x/exp/rand"
"gonum.org/v1/gonum/blas"
"gonum.org/v1/gonum/blas/blas64"
"gonum.org/v1/gonum/floats"
)
type Dgeql2er interface {
Dgeql2(m, n int, a []float64, lda int, tau, work []float64)
}
func Dgeql2Test(t *testing.T, impl Dgeql2er) {
const tol = 1e-14
rnd := rand.New(rand.NewSource(1))
// TODO(btracey): Add tests for m < n.
for _, test := range []struct {
m, n, lda int
}{
{5, 5, 0},
{5, 3, 0},
{5, 4, 0},
} {
m := test.m
n := test.n
lda := test.lda
if lda == 0 {
lda = n
}
a := make([]float64, m*lda)
for i := range a {
a[i] = rnd.NormFloat64()
}
tau := nanSlice(min(m, n))
work := nanSlice(n)
aCopy := make([]float64, len(a))
copy(aCopy, a)
impl.Dgeql2(m, n, a, lda, tau, work)
k := min(m, n)
// Construct Q.
q := blas64.General{
Rows: m,
Cols: m,
Stride: m,
Data: make([]float64, m*m),
}
for i := 0; i < m; i++ {
q.Data[i*q.Stride+i] = 1
}
for i := 0; i < k; i++ {
h := blas64.General{Rows: m, Cols: m, Stride: m, Data: make([]float64, m*m)}
for j := 0; j < m; j++ {
h.Data[j*h.Stride+j] = 1
}
v := blas64.Vector{Inc: 1, Data: make([]float64, m)}
v.Data[m-k+i] = 1
for j := 0; j < m-k+i; j++ {
v.Data[j] = a[j*lda+n-k+i]
}
blas64.Ger(-tau[i], v, v, h)
qTmp := blas64.General{Rows: q.Rows, Cols: q.Cols, Stride: q.Stride, Data: make([]float64, len(q.Data))}
copy(qTmp.Data, q.Data)
blas64.Gemm(blas.NoTrans, blas.NoTrans, 1, h, qTmp, 0, q)
}
if resid := residualOrthogonal(q, false); resid > tol {
t.Errorf("Q is not orthogonal; resid=%v, want<=%v", resid, tol)
}
l := blas64.General{
Rows: m,
Cols: n,
Stride: n,
Data: make([]float64, m*n),
}
if m >= n {
for i := m - n; i < m; i++ {
for j := 0; j <= min(i-(m-n), n-1); j++ {
l.Data[i*l.Stride+j] = a[i*lda+j]
}
}
} else {
panic("untested")
}
ans := blas64.General{Rows: m, Cols: n, Stride: lda, Data: make([]float64, len(a))}
copy(ans.Data, a)
blas64.Gemm(blas.NoTrans, blas.NoTrans, 1, q, l, 0, ans)
if !floats.EqualApprox(ans.Data, aCopy, tol) {
t.Errorf("Reconstruction mismatch: m = %v, n = %v", m, n)
}
}
}
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