| // Copyright ©2015 The gonum Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| package testlapack |
| |
| import ( |
| "math/rand" |
| "testing" |
| |
| "gonum.org/v1/gonum/floats" |
| ) |
| |
| type Dlasv2er interface { |
| Dlasv2(f, g, h float64) (ssmin, ssmax, snr, csr, snl, csl float64) |
| } |
| |
| func Dlasv2Test(t *testing.T, impl Dlasv2er) { |
| rnd := rand.New(rand.NewSource(1)) |
| for i := 0; i < 100; i++ { |
| f := rnd.NormFloat64() |
| g := rnd.NormFloat64() |
| h := rnd.NormFloat64() |
| |
| ssmin, ssmax, snr, csr, snl, csl := impl.Dlasv2(f, g, h) |
| |
| // tmp = |
| // [ csl snl] [f g] |
| // [-snl csl] [0 h] |
| tmp11 := csl * f |
| tmp12 := csl*g + snl*h |
| tmp21 := -snl * f |
| tmp22 := -snl*g + csl*h |
| // lhs = |
| // [tmp11 tmp12] [csr -snr] |
| // [tmp21 tmp22] [snr csr] |
| ans11 := tmp11*csr + tmp12*snr |
| ans12 := tmp11*-snr + tmp12*csr |
| ans21 := tmp21*csr + tmp22*snr |
| ans22 := tmp21*-snr + tmp22*csr |
| |
| lhs := []float64{ans11, ans12, ans21, ans22} |
| rhs := []float64{ssmax, 0, 0, ssmin} |
| if !floats.EqualApprox(rhs, lhs, 1e-12) { |
| t.Errorf("SVD mismatch. f = %v, g = %v, h = %v.\nLHS: %v\nRHS: %v", f, g, h, lhs, rhs) |
| } |
| } |
| } |