github.com/gopherd/gonum@v0.0.4/lapack/testlapack/dlas2.go (about)

     1  // Copyright ©2015 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  	"testing"
    10  )
    11  
    12  type Dlas2er interface {
    13  	Dlas2(f, g, h float64) (min, max float64)
    14  }
    15  
    16  func Dlas2Test(t *testing.T, impl Dlas2er) {
    17  	for i, test := range []struct {
    18  		f, g, h, ssmin, ssmax float64
    19  	}{
    20  		// Singular values computed from Octave.
    21  		{10, 30, 12, 3.567778859365365, 33.634371616111189},
    22  		{10, 30, -12, 3.567778859365365, 33.634371616111189},
    23  		{2, 30, -12, 0.741557056404952, 32.364333658088754},
    24  		{-2, 5, 12, 1.842864429909778, 13.023204317408728},
    25  	} {
    26  		ssmin, ssmax := impl.Dlas2(test.f, test.g, test.h)
    27  		if math.Abs(ssmin-test.ssmin) > 1e-12 {
    28  			t.Errorf("Case %d, minimal singular value mismatch. Want %v, got %v", i, test.ssmin, ssmin)
    29  		}
    30  		if math.Abs(ssmax-test.ssmax) > 1e-12 {
    31  			t.Errorf("Case %d, minimal singular value mismatch. Want %v, got %v", i, test.ssmin, ssmin)
    32  		}
    33  	}
    34  }