github.com/gonum/lapack@v0.0.0-20181123203213-e4cdc5a0bff9/testlapack/dgebak.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/rand"
    10  	"testing"
    11  
    12  	"github.com/gonum/blas"
    13  	"github.com/gonum/blas/blas64"
    14  	"github.com/gonum/lapack"
    15  )
    16  
    17  type Dgebaker interface {
    18  	Dgebak(job lapack.Job, side lapack.EVSide, n, ilo, ihi int, scale []float64, m int, v []float64, ldv int)
    19  }
    20  
    21  func DgebakTest(t *testing.T, impl Dgebaker) {
    22  	rnd := rand.New(rand.NewSource(1))
    23  
    24  	for _, job := range []lapack.Job{lapack.None, lapack.Permute, lapack.Scale, lapack.PermuteScale} {
    25  		for _, side := range []lapack.EVSide{lapack.LeftEV, lapack.RightEV} {
    26  			for _, n := range []int{0, 1, 2, 3, 4, 5, 6, 10, 18, 31, 53} {
    27  				for _, extra := range []int{0, 11} {
    28  					for cas := 0; cas < 100; cas++ {
    29  						m := rnd.Intn(n + 1)
    30  						v := randomGeneral(n, m, m+extra, rnd)
    31  						var ilo, ihi int
    32  						if v.Rows > 0 {
    33  							ihi = rnd.Intn(n)
    34  							ilo = rnd.Intn(ihi + 1)
    35  						} else {
    36  							ihi = -1
    37  						}
    38  						testDgebak(t, impl, job, side, ilo, ihi, v, rnd)
    39  					}
    40  				}
    41  			}
    42  		}
    43  	}
    44  }
    45  
    46  func testDgebak(t *testing.T, impl Dgebaker, job lapack.Job, side lapack.EVSide, ilo, ihi int, v blas64.General, rnd *rand.Rand) {
    47  	const tol = 1e-15
    48  	n := v.Rows
    49  	m := v.Cols
    50  	extra := v.Stride - v.Cols
    51  
    52  	// Create D and D^{-1} by generating random scales between ilo and ihi.
    53  	d := eye(n, n)
    54  	dinv := eye(n, n)
    55  	scale := nanSlice(n)
    56  	if job == lapack.Scale || job == lapack.PermuteScale {
    57  		if ilo == ihi {
    58  			scale[ilo] = 1
    59  		} else {
    60  			for i := ilo; i <= ihi; i++ {
    61  				scale[i] = 2 * rnd.Float64()
    62  				d.Data[i*d.Stride+i] = scale[i]
    63  				dinv.Data[i*dinv.Stride+i] = 1 / scale[i]
    64  			}
    65  		}
    66  	}
    67  
    68  	// Create P by generating random column swaps.
    69  	p := eye(n, n)
    70  	if job == lapack.Permute || job == lapack.PermuteScale {
    71  		// Make up some random permutations.
    72  		for i := n - 1; i > ihi; i-- {
    73  			scale[i] = float64(rnd.Intn(i + 1))
    74  			blas64.Swap(n,
    75  				blas64.Vector{p.Stride, p.Data[i:]},
    76  				blas64.Vector{p.Stride, p.Data[int(scale[i]):]})
    77  		}
    78  		for i := 0; i < ilo; i++ {
    79  			scale[i] = float64(i + rnd.Intn(ihi-i+1))
    80  			blas64.Swap(n,
    81  				blas64.Vector{p.Stride, p.Data[i:]},
    82  				blas64.Vector{p.Stride, p.Data[int(scale[i]):]})
    83  		}
    84  	}
    85  
    86  	got := cloneGeneral(v)
    87  	impl.Dgebak(job, side, n, ilo, ihi, scale, m, got.Data, got.Stride)
    88  
    89  	prefix := fmt.Sprintf("Case job=%v, side=%v, n=%v, ilo=%v, ihi=%v, m=%v, extra=%v",
    90  		job, side, n, ilo, ihi, m, extra)
    91  
    92  	if !generalOutsideAllNaN(got) {
    93  		t.Errorf("%v: out-of-range write to V\n%v", prefix, got.Data)
    94  	}
    95  
    96  	// Compute D*V or D^{-1}*V and store into dv.
    97  	dv := zeros(n, m, m)
    98  	if side == lapack.RightEV {
    99  		blas64.Gemm(blas.NoTrans, blas.NoTrans, 1, d, v, 0, dv)
   100  	} else {
   101  		blas64.Gemm(blas.NoTrans, blas.NoTrans, 1, dinv, v, 0, dv)
   102  	}
   103  	// Compute P*D*V or P*D^{-1}*V and store into want.
   104  	want := zeros(n, m, m)
   105  	blas64.Gemm(blas.NoTrans, blas.NoTrans, 1, p, dv, 0, want)
   106  
   107  	if !equalApproxGeneral(want, got, tol) {
   108  		t.Errorf("%v: unexpected value of V", prefix)
   109  	}
   110  }