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93 lines
2.1 KiB
Go
93 lines
2.1 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/blas"
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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 Dgtsver interface {
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Dgtsv(n, nrhs int, dl, d, du []float64, b []float64, ldb int) (ok bool)
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}
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func DgtsvTest(t *testing.T, impl Dgtsver) {
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rnd := rand.New(rand.NewSource(1))
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for _, n := range []int{0, 1, 2, 3, 4, 5, 10, 25, 50} {
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for _, nrhs := range []int{0, 1, 2, 3, 4, 10} {
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for _, ldb := range []int{max(1, nrhs), nrhs + 3} {
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dgtsvTest(t, impl, rnd, n, nrhs, ldb)
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}
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}
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}
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}
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func dgtsvTest(t *testing.T, impl Dgtsver, rnd *rand.Rand, n, nrhs, ldb 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("Case n=%d,nrhs=%d,ldb=%d", n, nrhs, ldb)
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if n == 0 {
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ok := impl.Dgtsv(n, nrhs, nil, nil, nil, nil, ldb)
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if !ok {
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t.Errorf("%v: unexpected failure for zero size matrix", name)
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}
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return
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}
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// Generate three random diagonals.
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var (
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d, dCopy []float64
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dl, dlCopy []float64
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du, duCopy []float64
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)
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d = randomSlice(n+1+extra, rnd)
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dCopy = make([]float64, len(d))
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copy(dCopy, d)
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if n > 1 {
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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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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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}
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b := randomGeneral(n, nrhs, ldb, rnd)
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got := cloneGeneral(b)
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ok := impl.Dgtsv(n, nrhs, dl, d, du, got.Data, got.Stride)
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if !ok {
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t.Fatalf("%v: unexpected failure in Dgtsv", name)
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return
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}
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// Compute A*X - B.
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dlagtm(blas.NoTrans, n, nrhs, 1, dlCopy, dCopy, duCopy, got.Data, got.Stride, -1, b.Data, b.Stride)
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anorm := dlangt(lapack.MaxColumnSum, n, dlCopy, dCopy, duCopy)
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bi := blas64.Implementation()
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var resid float64
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for j := 0; j < nrhs; j++ {
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bnorm := bi.Dasum(n, b.Data[j:], b.Stride)
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xnorm := bi.Dasum(n, got.Data[j:], got.Stride)
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resid = math.Max(resid, bnorm/anorm/xnorm)
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}
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if resid > tol {
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t.Errorf("%v: unexpected result; resid=%v,want<=%v", name, resid, tol)
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}
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}
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