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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. tau := make([]float64, n) for i := 0; i < n; i++ { 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) } } } }