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123 lines
3.0 KiB
Go
123 lines
3.0 KiB
Go
// Copyright ©2020 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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"fmt"
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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/floats"
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"gonum.org/v1/gonum/lapack"
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)
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type Dlangter interface {
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Dlangt(norm lapack.MatrixNorm, n int, dl, d, du []float64) float64
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}
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func DlangtTest(t *testing.T, impl Dlangter) {
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rnd := rand.New(rand.NewSource(1))
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for _, norm := range []lapack.MatrixNorm{lapack.MaxAbs, lapack.MaxRowSum, lapack.MaxColumnSum, lapack.Frobenius} {
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t.Run(normToString(norm), func(t *testing.T) {
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for _, n := range []int{0, 1, 2, 3, 4, 5, 10} {
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for iter := 0; iter < 10; iter++ {
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dlangtTest(t, impl, rnd, norm, n)
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}
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}
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})
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}
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}
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func dlangtTest(t *testing.T, impl Dlangter, rnd *rand.Rand, norm lapack.MatrixNorm, n int) {
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const (
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tol = 1e-14
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extra = 10
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)
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name := fmt.Sprintf("n=%v", n)
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// Generate three random diagonals.
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dl := randomSlice(n+extra, rnd)
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dlCopy := make([]float64, len(dl))
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copy(dlCopy, dl)
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d := randomSlice(n+1+extra, rnd)
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// Sometimes put a NaN into the matrix.
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if n > 0 && rnd.Float64() < 0.5 {
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d[rnd.Intn(n)] = math.NaN()
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}
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dCopy := make([]float64, len(d))
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copy(dCopy, d)
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du := randomSlice(n+extra, rnd)
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duCopy := make([]float64, len(du))
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copy(duCopy, du)
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// Deal with zero-sized matrices early.
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if n == 0 {
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got := impl.Dlangt(norm, n, nil, nil, nil)
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if got != 0 {
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t.Errorf("%v: unexpected result for zero-sized matrix with nil input", name)
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}
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got = impl.Dlangt(norm, n, dl, d, du)
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if !floats.Same(dl, dlCopy) {
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t.Errorf("%v: unexpected modification in dl", name)
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}
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if !floats.Same(d, dCopy) {
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t.Errorf("%v: unexpected modification in d", name)
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}
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if !floats.Same(du, duCopy) {
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t.Errorf("%v: unexpected modification in du", name)
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}
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if got != 0 {
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t.Errorf("%v: unexpected result for zero-sized matrix with non-nil input", name)
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}
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return
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}
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// Generate a dense representation of the matrix and compute the wanted result.
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a := zeros(n, n, n)
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for i := 0; i < n-1; i++ {
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a.Data[i*a.Stride+i] = d[i]
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a.Data[i*a.Stride+i+1] = du[i]
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a.Data[(i+1)*a.Stride+i] = dl[i]
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}
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a.Data[(n-1)*a.Stride+n-1] = d[n-1]
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got := impl.Dlangt(norm, n, dl, d, du)
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if !floats.Same(dl, dlCopy) {
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t.Errorf("%v: unexpected modification in dl", name)
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}
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if !floats.Same(d, dCopy) {
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t.Errorf("%v: unexpected modification in d", name)
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}
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if !floats.Same(du, duCopy) {
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t.Errorf("%v: unexpected modification in du", name)
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}
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want := dlange(norm, n, n, a.Data, a.Stride)
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if math.IsNaN(want) {
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if !math.IsNaN(got) {
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t.Errorf("%v: unexpected result with NaN element; got %v, want %v", name, got, want)
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}
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return
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}
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if norm == lapack.MaxAbs {
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if got != want {
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t.Errorf("%v: unexpected result; got %v, want %v", name, got, want)
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}
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return
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}
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diff := math.Abs(got - want)
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if diff > tol {
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t.Errorf("%v: unexpected result; got %v, want %v, diff=%v", name, got, want, diff)
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}
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}
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