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// Copyright ©2015 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/floats"
)
type Dgeqrfer interface {
Dgeqr2er
Dgeqrf(m, n int, a []float64, lda int, tau, work []float64, lwork int)
}
func DgeqrfTest(t *testing.T, impl Dgeqrfer) {
const tol = 1e-12
rnd := rand.New(rand.NewSource(1))
for c, test := range []struct {
m, n, lda int
}{
{10, 5, 0},
{5, 10, 0},
{10, 10, 0},
{300, 5, 0},
{3, 500, 0},
{200, 200, 0},
{300, 200, 0},
{204, 300, 0},
{1, 3000, 0},
{3000, 1, 0},
{10, 5, 20},
{5, 10, 20},
{10, 10, 20},
{300, 5, 400},
{3, 500, 600},
{200, 200, 300},
{300, 200, 300},
{204, 300, 400},
{1, 3000, 4000},
{3000, 1, 4000},
} {
m := test.m
n := test.n
lda := test.lda
if lda == 0 {
lda = test.n
}
// Allocate m×n matrix A and fill it with random numbers.
a := make([]float64, m*lda)
for i := range a {
a[i] = rnd.NormFloat64()
}
// Store a copy of A for later comparison.
aCopy := make([]float64, len(a))
copy(aCopy, a)
// Allocate a slice for scalar factors of elementary reflectors
// and fill it with random numbers.
k := min(m, n)
tau := make([]float64, k)
for i := range tau {
tau[i] = rnd.Float64()
}
// Compute the expected result using unblocked QR algorithm and
// store it in want.
want := make([]float64, len(a))
copy(want, a)
impl.Dgeqr2(m, n, want, lda, tau, make([]float64, n))
for _, wl := range []worklen{minimumWork, mediumWork, optimumWork} {
copy(a, aCopy)
var lwork int
switch wl {
case minimumWork:
lwork = n
case mediumWork:
work := make([]float64, 1)
impl.Dgeqrf(m, n, a, lda, tau, work, -1)
lwork = int(work[0]) - 2*n
case optimumWork:
work := make([]float64, 1)
impl.Dgeqrf(m, n, a, lda, tau, work, -1)
lwork = int(work[0])
}
work := make([]float64, lwork)
// Compute the QR factorization of A.
impl.Dgeqrf(m, n, a, lda, tau, work, len(work))
// Compare the result with Dgeqr2.
if !floats.EqualApprox(want, a, tol) {
t.Errorf("Case %v, workspace %v, unexpected result.", c, wl)
}
}
}
}
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