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.
10 "golang.org/x/exp/rand"
12 "gonum.org/v1/gonum/floats"
15 type Dlasv2er interface {
16 Dlasv2(f, g, h float64) (ssmin, ssmax, snr, csr, snl, csl float64)
19 func Dlasv2Test(t *testing.T, impl Dlasv2er) {
20 rnd := rand.New(rand.NewSource(1))
21 for i := 0; i < 100; i++ {
22 f := rnd.NormFloat64()
23 g := rnd.NormFloat64()
24 h := rnd.NormFloat64()
26 ssmin, ssmax, snr, csr, snl, csl := impl.Dlasv2(f, g, h)
32 tmp12 := csl*g + snl*h
34 tmp22 := -snl*g + csl*h
36 // [tmp11 tmp12] [csr -snr]
37 // [tmp21 tmp22] [snr csr]
38 ans11 := tmp11*csr + tmp12*snr
39 ans12 := tmp11*-snr + tmp12*csr
40 ans21 := tmp21*csr + tmp22*snr
41 ans22 := tmp21*-snr + tmp22*csr
43 lhs := []float64{ans11, ans12, ans21, ans22}
44 rhs := []float64{ssmax, 0, 0, ssmin}
45 if !floats.EqualApprox(rhs, lhs, 1e-12) {
46 t.Errorf("SVD mismatch. f = %v, g = %v, h = %v.\nLHS: %v\nRHS: %v", f, g, h, lhs, rhs)