gonum/testlapack/dormbr.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/rand"
	"testing"

	"github.com/gonum/blas"
	"github.com/gonum/blas/blas64"
	"github.com/gonum/floats"
	"github.com/gonum/lapack"
)

type Dormbrer interface {
	Dormbr(vect lapack.DecompUpdate, side blas.Side, trans blas.Transpose, m, n, k int, a []float64, lda int, tau, c []float64, ldc int, work []float64, lwork int)
	Dgebrder
}

func DormbrTest(t *testing.T, impl Dormbrer) {
	rnd := rand.New(rand.NewSource(1))
	bi := blas64.Implementation()
	for _, vect := range []lapack.DecompUpdate{lapack.ApplyQ, lapack.ApplyP} {
		for _, side := range []blas.Side{blas.Left, blas.Right} {
			for _, trans := range []blas.Transpose{blas.NoTrans, blas.Trans} {
				for _, test := range []struct {
					m, n, k, lda, ldc int
				}{
					{3, 4, 5, 0, 0},
					{3, 5, 4, 0, 0},
					{4, 3, 5, 0, 0},
					{4, 5, 3, 0, 0},
					{5, 3, 4, 0, 0},
					{5, 4, 3, 0, 0},

					{3, 4, 5, 10, 12},
					{3, 5, 4, 10, 12},
					{4, 3, 5, 10, 12},
					{4, 5, 3, 10, 12},
					{5, 3, 4, 10, 12},
					{5, 4, 3, 10, 12},
				} {
					m := test.m
					n := test.n
					k := test.k
					ldc := test.ldc
					if ldc == 0 {
						ldc = n
					}
					nq := n
					if side == blas.Left {
						nq = m
					}

					// Compute a decomposition.
					var ma, na int
					var a []float64
					if vect == lapack.ApplyQ {
						ma = nq
						na = k
					} else {
						ma = k
						na = nq
					}
					lda := test.lda
					if lda == 0 {
						lda = na
					}
					a = make([]float64, ma*lda)
					for i := range a {
						a[i] = rnd.NormFloat64()
					}
					nTau := min(nq, k)
					tauP := make([]float64, nTau)
					tauQ := make([]float64, nTau)
					d := make([]float64, nTau)
					e := make([]float64, nTau)
					lwork := -1
					work := make([]float64, 1)
					impl.Dgebrd(ma, na, a, lda, d, e, tauQ, tauP, work, lwork)
					work = make([]float64, int(work[0]))
					lwork = len(work)

					impl.Dgebrd(ma, na, a, lda, d, e, tauQ, tauP, work, lwork)

					// Apply and compare update.
					c := make([]float64, m*ldc)
					for i := range c {
						c[i] = rnd.NormFloat64()
					}

					cCopy := make([]float64, len(c))
					copy(cCopy, c)

					if vect == lapack.ApplyQ {
						impl.Dormbr(vect, side, trans, m, n, k, a, lda, tauQ, c, ldc, work, lwork)
					} else {
						impl.Dormbr(vect, side, trans, m, n, k, a, lda, tauP, c, ldc, work, lwork)
					}

					// Check that the multiplication was correct.
					cOrig := blas64.General{
						Rows:   m,
						Cols:   n,
						Stride: ldc,
						Data:   make([]float64, len(cCopy)),
					}
					copy(cOrig.Data, cCopy)
					cAns := blas64.General{
						Rows:   m,
						Cols:   n,
						Stride: ldc,
						Data:   make([]float64, len(cCopy)),
					}
					copy(cAns.Data, cCopy)
					nb := min(ma, na)
					var mulMat blas64.General
					if vect == lapack.ApplyQ {
						mulMat = constructQPBidiagonal(lapack.ApplyQ, ma, na, nb, a, lda, tauQ)
					} else {
						mulMat = constructQPBidiagonal(lapack.ApplyP, ma, na, nb, a, lda, tauP)
					}

					mulTrans := trans

					if side == blas.Left {
						bi.Dgemm(mulTrans, blas.NoTrans, m, n, m, 1, mulMat.Data, mulMat.Stride, cOrig.Data, cOrig.Stride, 0, cAns.Data, cAns.Stride)
					} else {
						bi.Dgemm(blas.NoTrans, mulTrans, m, n, n, 1, cOrig.Data, cOrig.Stride, mulMat.Data, mulMat.Stride, 0, cAns.Data, cAns.Stride)
					}

					if !floats.EqualApprox(cAns.Data, c, 1e-8) {
						isApplyQ := vect == lapack.ApplyQ
						isLeft := side == blas.Left
						isTrans := trans == blas.Trans

						t.Errorf("C mismatch. isApplyQ: %v, isLeft: %v, isTrans: %v, m = %v, n = %v, k = %v, lda = %v, ldc = %v",
							isApplyQ, isLeft, isTrans, m, n, k, lda, ldc)
					}
				}
			}
		}
	}
}