github.com/gonum/lapack@v0.0.0-20181123203213-e4cdc5a0bff9/testlapack/dlanst.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  	"math"
     9  	"math/rand"
    10  	"testing"
    11  
    12  	"github.com/gonum/lapack"
    13  )
    14  
    15  type Dlanster interface {
    16  	Dlanst(norm lapack.MatrixNorm, n int, d, e []float64) float64
    17  	Dlanger
    18  }
    19  
    20  func DlanstTest(t *testing.T, impl Dlanster) {
    21  	rnd := rand.New(rand.NewSource(1))
    22  	for _, norm := range []lapack.MatrixNorm{lapack.MaxAbs, lapack.MaxColumnSum, lapack.MaxRowSum, lapack.NormFrob} {
    23  		for _, n := range []int{1, 3, 10, 100} {
    24  			for cas := 0; cas < 100; cas++ {
    25  				d := make([]float64, n)
    26  				for i := range d {
    27  					d[i] = rnd.NormFloat64()
    28  				}
    29  				e := make([]float64, n-1)
    30  				for i := range e {
    31  					e[i] = rnd.NormFloat64()
    32  				}
    33  
    34  				m := n
    35  				lda := n
    36  				a := make([]float64, m*lda)
    37  				for i := 0; i < n; i++ {
    38  					a[i*lda+i] = d[i]
    39  				}
    40  				for i := 0; i < n-1; i++ {
    41  					a[i*lda+i+1] = e[i]
    42  					a[(i+1)*lda+i] = e[i]
    43  				}
    44  				work := make([]float64, n)
    45  				syNorm := impl.Dlanst(norm, n, d, e)
    46  				geNorm := impl.Dlange(norm, m, n, a, lda, work)
    47  				if math.Abs(syNorm-geNorm) > 1e-12 {
    48  					t.Errorf("Norm mismatch: norm = %v, cas = %v, n = %v. Want %v, got %v.", string(norm), cas, n, geNorm, syNorm)
    49  				}
    50  			}
    51  		}
    52  	}
    53  }