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102 lines
2.5 KiB
Go
102 lines
2.5 KiB
Go
// Copyright ©2015 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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"math"
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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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"gonum.org/v1/gonum/lapack"
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)
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type Dlanger interface {
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Dlange(norm lapack.MatrixNorm, m, n int, a []float64, lda int, work []float64) float64
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}
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func DlangeTest(t *testing.T, impl Dlanger) {
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rnd := rand.New(rand.NewSource(1))
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for _, test := range []struct {
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m, n, lda int
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}{
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{4, 3, 0},
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{3, 4, 0},
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{4, 3, 100},
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{3, 4, 100},
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} {
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m := test.m
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n := test.n
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lda := test.lda
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if lda == 0 {
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lda = n
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}
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// Allocate m×n matrix A and fill it with random numbers from [-0.5, 0.5).
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a := make([]float64, m*lda)
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for i := range a {
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a[i] = rnd.Float64() - 0.5
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}
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// Store a copy of A for later comparison.
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aCopy := make([]float64, len(a))
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copy(aCopy, a)
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// Allocate workspace slice.
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work := make([]float64, n)
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for i := range work {
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work[i] = rnd.Float64()
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}
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// Test various norms by comparing the result from Dlange with
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// explicit calculation.
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// Test MaxAbs norm.
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norm := impl.Dlange(lapack.MaxAbs, m, n, a, lda, work)
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var ans float64
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for i := 0; i < m; i++ {
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idx := blas64.Iamax(blas64.Vector{N: n, Inc: 1, Data: aCopy[i*lda:]})
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ans = math.Max(ans, math.Abs(a[i*lda+idx]))
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}
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// Should be strictly equal because there is no floating point summation error.
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if ans != norm {
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t.Errorf("MaxAbs mismatch. Want %v, got %v.", ans, norm)
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}
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// Test MaxColumnSum norm.
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norm = impl.Dlange(lapack.MaxColumnSum, m, n, a, lda, work)
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ans = 0
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for i := 0; i < n; i++ {
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sum := blas64.Asum(blas64.Vector{N: m, Inc: lda, Data: aCopy[i:]})
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ans = math.Max(ans, sum)
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}
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if math.Abs(norm-ans) > 1e-14 {
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t.Errorf("MaxColumnSum mismatch. Want %v, got %v.", ans, norm)
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}
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// Test MaxRowSum norm.
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norm = impl.Dlange(lapack.MaxRowSum, m, n, a, lda, work)
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ans = 0
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for i := 0; i < m; i++ {
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sum := blas64.Asum(blas64.Vector{N: n, Inc: 1, Data: aCopy[i*lda:]})
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ans = math.Max(ans, sum)
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}
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if math.Abs(norm-ans) > 1e-14 {
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t.Errorf("MaxRowSum mismatch. Want %v, got %v.", ans, norm)
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}
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// Test Frobenius norm.
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norm = impl.Dlange(lapack.Frobenius, m, n, a, lda, work)
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ans = 0
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for i := 0; i < m; i++ {
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sum := blas64.Nrm2(blas64.Vector{N: n, Inc: 1, Data: aCopy[i*lda:]})
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ans += sum * sum
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}
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ans = math.Sqrt(ans)
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if math.Abs(norm-ans) > 1e-14 {
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t.Errorf("Frobenius norm mismatch. Want %v, got %v.", ans, norm)
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}
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}
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}
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