github.com/gonum/lapack@v0.0.0-20181123203213-e4cdc5a0bff9/testlapack/dlasy2.go (about)

     1  // Copyright ©2016 The gonum Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package testlapack
     6  
     7  import (
     8  	"fmt"
     9  	"math"
    10  	"math/rand"
    11  	"testing"
    12  
    13  	"github.com/gonum/blas"
    14  	"github.com/gonum/blas/blas64"
    15  )
    16  
    17  type Dlasy2er interface {
    18  	Dlasy2(tranl, tranr bool, isgn, n1, n2 int, tl []float64, ldtl int, tr []float64, ldtr int, b []float64, ldb int, x []float64, ldx int) (scale, xnorm float64, ok bool)
    19  }
    20  
    21  func Dlasy2Test(t *testing.T, impl Dlasy2er) {
    22  	rnd := rand.New(rand.NewSource(1))
    23  	for _, tranl := range []bool{true, false} {
    24  		for _, tranr := range []bool{true, false} {
    25  			for _, isgn := range []int{1, -1} {
    26  				for _, n1 := range []int{0, 1, 2} {
    27  					for _, n2 := range []int{0, 1, 2} {
    28  						for _, extra := range []int{0, 1, 2, 13} {
    29  							for cas := 0; cas < 1000; cas++ {
    30  								testDlasy2(t, impl, tranl, tranr, isgn, n1, n2, extra, rnd)
    31  							}
    32  						}
    33  					}
    34  				}
    35  			}
    36  		}
    37  	}
    38  }
    39  
    40  func testDlasy2(t *testing.T, impl Dlasy2er, tranl, tranr bool, isgn, n1, n2, extra int, rnd *rand.Rand) {
    41  	const tol = 1e-11
    42  
    43  	tl := randomGeneral(n1, n1, n1+extra, rnd)
    44  	tr := randomGeneral(n2, n2, n2+extra, rnd)
    45  	b := randomGeneral(n1, n2, n2+extra, rnd)
    46  	x := randomGeneral(n1, n2, n2+extra, rnd)
    47  
    48  	scale, xnorm, ok := impl.Dlasy2(tranl, tranr, isgn, n1, n2, tl.Data, tl.Stride, tr.Data, tr.Stride, b.Data, b.Stride, x.Data, x.Stride)
    49  	if scale > 1 {
    50  		t.Errorf("invalid value of scale, want <= 1, got %v", scale)
    51  	}
    52  	if n1 == 0 || n2 == 0 {
    53  		return
    54  	}
    55  
    56  	prefix := fmt.Sprintf("Case n1=%v, n2=%v, isgn=%v", n1, n2, isgn)
    57  
    58  	// Check any invalid modifications of x.
    59  	if !generalOutsideAllNaN(x) {
    60  		t.Errorf("%v: out-of-range write to x\n%v", prefix, x.Data)
    61  	}
    62  
    63  	var xnormWant float64
    64  	for i := 0; i < n1; i++ {
    65  		var rowsum float64
    66  		for j := 0; j < n2; j++ {
    67  			rowsum += math.Abs(x.Data[i*x.Stride+j])
    68  		}
    69  		if rowsum > xnormWant {
    70  			xnormWant = rowsum
    71  		}
    72  	}
    73  	if xnormWant != xnorm {
    74  		t.Errorf("%v: unexpected xnorm: want %v, got %v", prefix, xnormWant, xnorm)
    75  	}
    76  
    77  	// Multiply b by scale to get the wanted right-hand side.
    78  	for i := 0; i < n1; i++ {
    79  		for j := 0; j < n2; j++ {
    80  			b.Data[i*b.Stride+j] *= scale
    81  		}
    82  	}
    83  	// Compute the wanted left-hand side.
    84  	lhsWant := randomGeneral(n1, n2, n2, rnd)
    85  	if tranl {
    86  		blas64.Gemm(blas.Trans, blas.NoTrans, 1, tl, x, 0, lhsWant)
    87  	} else {
    88  		blas64.Gemm(blas.NoTrans, blas.NoTrans, 1, tl, x, 0, lhsWant)
    89  	}
    90  	if tranr {
    91  		blas64.Gemm(blas.NoTrans, blas.Trans, float64(isgn), x, tr, 1, lhsWant)
    92  	} else {
    93  		blas64.Gemm(blas.NoTrans, blas.NoTrans, float64(isgn), x, tr, 1, lhsWant)
    94  	}
    95  	// Compare them.
    96  	for i := 0; i < n1; i++ {
    97  		for j := 0; j < n2; j++ {
    98  			diff := lhsWant.Data[i*lhsWant.Stride+j] - b.Data[i*b.Stride+j]
    99  			if math.Abs(diff) > tol && ok {
   100  				t.Errorf("%v: unexpected result, diff[%v,%v]=%v", prefix, i, j, diff)
   101  			}
   102  		}
   103  	}
   104  }