mirror of
https://github.com/gonum/gonum.git
synced 2025-10-31 02:26:59 +08:00
102 lines
2.5 KiB
Go
102 lines
2.5 KiB
Go
// 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 (
|
||
"math"
|
||
"testing"
|
||
|
||
"golang.org/x/exp/rand"
|
||
|
||
"gonum.org/v1/gonum/blas/blas64"
|
||
"gonum.org/v1/gonum/lapack"
|
||
)
|
||
|
||
type Dlanger interface {
|
||
Dlange(norm lapack.MatrixNorm, m, n int, a []float64, lda int, work []float64) float64
|
||
}
|
||
|
||
func DlangeTest(t *testing.T, impl Dlanger) {
|
||
rnd := rand.New(rand.NewSource(1))
|
||
for _, test := range []struct {
|
||
m, n, lda int
|
||
}{
|
||
{4, 3, 0},
|
||
{3, 4, 0},
|
||
{4, 3, 100},
|
||
{3, 4, 100},
|
||
} {
|
||
m := test.m
|
||
n := test.n
|
||
lda := test.lda
|
||
if lda == 0 {
|
||
lda = n
|
||
}
|
||
// Allocate m×n matrix A and fill it with random numbers from [-0.5, 0.5).
|
||
a := make([]float64, m*lda)
|
||
for i := range a {
|
||
a[i] = rnd.Float64() - 0.5
|
||
}
|
||
// Store a copy of A for later comparison.
|
||
aCopy := make([]float64, len(a))
|
||
copy(aCopy, a)
|
||
|
||
// Allocate workspace slice.
|
||
work := make([]float64, n)
|
||
for i := range work {
|
||
work[i] = rnd.Float64()
|
||
}
|
||
|
||
// Test various norms by comparing the result from Dlange with
|
||
// explicit calculation.
|
||
|
||
// Test MaxAbs norm.
|
||
norm := impl.Dlange(lapack.MaxAbs, m, n, a, lda, work)
|
||
var ans float64
|
||
for i := 0; i < m; i++ {
|
||
idx := blas64.Iamax(blas64.Vector{N: n, Inc: 1, Data: aCopy[i*lda:]})
|
||
ans = math.Max(ans, math.Abs(a[i*lda+idx]))
|
||
}
|
||
// Should be strictly equal because there is no floating point summation error.
|
||
if ans != norm {
|
||
t.Errorf("MaxAbs mismatch. Want %v, got %v.", ans, norm)
|
||
}
|
||
|
||
// Test MaxColumnSum norm.
|
||
norm = impl.Dlange(lapack.MaxColumnSum, m, n, a, lda, work)
|
||
ans = 0
|
||
for i := 0; i < n; i++ {
|
||
sum := blas64.Asum(blas64.Vector{N: m, Inc: lda, Data: aCopy[i:]})
|
||
ans = math.Max(ans, sum)
|
||
}
|
||
if math.Abs(norm-ans) > 1e-14 {
|
||
t.Errorf("MaxColumnSum mismatch. Want %v, got %v.", ans, norm)
|
||
}
|
||
|
||
// Test MaxRowSum norm.
|
||
norm = impl.Dlange(lapack.MaxRowSum, m, n, a, lda, work)
|
||
ans = 0
|
||
for i := 0; i < m; i++ {
|
||
sum := blas64.Asum(blas64.Vector{N: n, Inc: 1, Data: aCopy[i*lda:]})
|
||
ans = math.Max(ans, sum)
|
||
}
|
||
if math.Abs(norm-ans) > 1e-14 {
|
||
t.Errorf("MaxRowSum mismatch. Want %v, got %v.", ans, norm)
|
||
}
|
||
|
||
// Test Frobenius norm.
|
||
norm = impl.Dlange(lapack.Frobenius, m, n, a, lda, work)
|
||
ans = 0
|
||
for i := 0; i < m; i++ {
|
||
sum := blas64.Nrm2(blas64.Vector{N: n, Inc: 1, Data: aCopy[i*lda:]})
|
||
ans += sum * sum
|
||
}
|
||
ans = math.Sqrt(ans)
|
||
if math.Abs(norm-ans) > 1e-14 {
|
||
t.Errorf("Frobenius norm mismatch. Want %v, got %v.", ans, norm)
|
||
}
|
||
}
|
||
}
|