mirror of
https://github.com/gonum/gonum.git
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116 lines
3.3 KiB
Go
116 lines
3.3 KiB
Go
// Copyright ©2018 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 testblas
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import (
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"fmt"
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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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)
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type Ztbsver interface {
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Ztbsv(uplo blas.Uplo, trans blas.Transpose, diag blas.Diag, n, k int, ab []complex128, ldab int, x []complex128, incX int)
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Ztbmver
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}
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func ZtbsvTest(t *testing.T, impl Ztbsver) {
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rnd := rand.New(rand.NewSource(1))
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for _, uplo := range []blas.Uplo{blas.Upper, blas.Lower} {
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for _, trans := range []blas.Transpose{blas.NoTrans, blas.Trans, blas.ConjTrans} {
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for _, diag := range []blas.Diag{blas.NonUnit, blas.Unit} {
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for _, n := range []int{1, 2, 3, 4, 10} {
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for k := 0; k < n; k++ {
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for _, ldab := range []int{k + 1, k + 1 + 10} {
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for _, incX := range []int{-4, 1, 5} {
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ztbsvTest(t, impl, rnd, uplo, trans, diag, n, k, ldab, incX)
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}
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}
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}
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}
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}
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}
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}
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}
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// ztbsvTest tests Ztbsv by checking whether Ztbmv followed by Ztbsv
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// round-trip.
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func ztbsvTest(t *testing.T, impl Ztbsver, rnd *rand.Rand, uplo blas.Uplo, trans blas.Transpose, diag blas.Diag, n, k, ldab, incX int) {
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const tol = 1e-10
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// Allocate a dense-storage triangular band matrix filled with NaNs that
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// will be used as a for creating the actual triangular band matrix.
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lda := max(1, n)
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a := makeZGeneral(nil, n, n, lda)
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// Fill the referenced triangle of A with random data within the band
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// and with zeros outside.
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if uplo == blas.Upper {
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for i := 0; i < n; i++ {
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for j := i; j < min(n, i+k+1); j++ {
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re := rnd.NormFloat64()
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im := rnd.NormFloat64()
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a[i*lda+j] = complex(re, im)
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}
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for j := i + k + 1; j < n; j++ {
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a[i*lda+j] = 0
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}
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}
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} else {
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for i := 0; i < n; i++ {
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for j := 0; j < i-k; j++ {
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a[i*lda+j] = 0
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}
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for j := max(0, i-k); j <= i; j++ {
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re := rnd.NormFloat64()
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im := rnd.NormFloat64()
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a[i*lda+j] = complex(re, im)
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}
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}
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}
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if diag == blas.Unit {
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// The diagonal should not be referenced by Ztbmv and Ztbsv, so
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// invalidate it with NaNs.
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for i := 0; i < n; i++ {
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a[i*lda+i] = znan
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}
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}
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// Create the triangular band matrix.
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ab := zPackTriBand(k, ldab, uplo, n, a, lda)
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abCopy := make([]complex128, len(ab))
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copy(abCopy, ab)
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// Generate a random complex vector x.
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xtest := make([]complex128, n)
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for i := range xtest {
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re := rnd.NormFloat64()
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im := rnd.NormFloat64()
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xtest[i] = complex(re, im)
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}
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x := makeZVector(xtest, incX)
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// Store a copy of x as the correct result that we want.
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want := make([]complex128, len(x))
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copy(want, x)
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// Compute A*x, denoting the result by b and storing it in x.
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impl.Ztbmv(uplo, trans, diag, n, k, ab, ldab, x, incX)
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// Solve A*x = b, that is, x = A^{-1}*b = A^{-1}*A*x.
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impl.Ztbsv(uplo, trans, diag, n, k, ab, ldab, x, incX)
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// If Ztbsv is correct, A^{-1}*A = I and x contains again its original value.
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name := fmt.Sprintf("uplo=%v,trans=%v,diag=%v,n=%v,k=%v,ldab=%v,incX=%v", uplo, trans, diag, n, k, ldab, incX)
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if !zsame(ab, abCopy) {
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t.Errorf("%v: unexpected modification of A", name)
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}
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if !zSameAtNonstrided(x, want, incX) {
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t.Errorf("%v: unexpected modification of x\nwant %v\ngot %v", name, want, x)
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}
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if !zEqualApproxAtStrided(x, want, incX, tol) {
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t.Errorf("%v: unexpected result\nwant %v\ngot %v", name, want, x)
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}
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}
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