Merge pull request #201 from Bytom/v0.1

[bytom/vapor.git] / vendor / gonum.org / v1 / gonum / lapack / gonum / dlasv2.go

diff --git a/vendor/gonum.org/v1/gonum/lapack/gonum/dlasv2.go b/vendor/gonum.org/v1/gonum/lapack/gonum/dlasv2.go
deleted file mode 100644 (file)
index 204af19..0000000
--- a/vendor/gonum.org/v1/gonum/lapack/gonum/dlasv2.go
+++ /dev/null
@@ -1,115 +0,0 @@
-// 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 gonum
-
-import "math"
-
-// Dlasv2 computes the singular value decomposition of a 2×2 matrix.
-//  [ csl snl] [f g] [csr -snr] = [ssmax     0]
-//  [-snl csl] [0 h] [snr  csr] = [    0 ssmin]
-// ssmax is the larger absolute singular value, and ssmin is the smaller absolute
-// singular value. [cls, snl] and [csr, snr] are the left and right singular vectors.
-//
-// Dlasv2 is an internal routine. It is exported for testing purposes.
-func (impl Implementation) Dlasv2(f, g, h float64) (ssmin, ssmax, snr, csr, snl, csl float64) {
-       ft := f
-       fa := math.Abs(ft)
-       ht := h
-       ha := math.Abs(h)
-       // pmax points to the largest element of the matrix in terms of absolute value.
-       // 1 if F, 2 if G, 3 if H.
-       pmax := 1
-       swap := ha > fa
-       if swap {
-               pmax = 3
-               ft, ht = ht, ft
-               fa, ha = ha, fa
-       }
-       gt := g
-       ga := math.Abs(gt)
-       var clt, crt, slt, srt float64
-       if ga == 0 {
-               ssmin = ha
-               ssmax = fa
-               clt = 1
-               crt = 1
-               slt = 0
-               srt = 0
-       } else {
-               gasmall := true
-               if ga > fa {
-                       pmax = 2
-                       if (fa / ga) < dlamchE {
-                               gasmall = false
-                               ssmax = ga
-                               if ha > 1 {
-                                       ssmin = fa / (ga / ha)
-                               } else {
-                                       ssmin = (fa / ga) * ha
-                               }
-                               clt = 1
-                               slt = ht / gt
-                               srt = 1
-                               crt = ft / gt
-                       }
-               }
-               if gasmall {
-                       d := fa - ha
-                       l := d / fa
-                       if d == fa { // deal with inf
-                               l = 1
-                       }
-                       m := gt / ft
-                       t := 2 - l
-                       s := math.Hypot(t, m)
-                       var r float64
-                       if l == 0 {
-                               r = math.Abs(m)
-                       } else {
-                               r = math.Hypot(l, m)
-                       }
-                       a := 0.5 * (s + r)
-                       ssmin = ha / a
-                       ssmax = fa * a
-                       if m == 0 {
-                               if l == 0 {
-                                       t = math.Copysign(2, ft) * math.Copysign(1, gt)
-                               } else {
-                                       t = gt/math.Copysign(d, ft) + m/t
-                               }
-                       } else {
-                               t = (m/(s+t) + m/(r+l)) * (1 + a)
-                       }
-                       l = math.Hypot(t, 2)
-                       crt = 2 / l
-                       srt = t / l
-                       clt = (crt + srt*m) / a
-                       slt = (ht / ft) * srt / a
-               }
-       }
-       if swap {
-               csl = srt
-               snl = crt
-               csr = slt
-               snr = clt
-       } else {
-               csl = clt
-               snl = slt
-               csr = crt
-               snr = srt
-       }
-       var tsign float64
-       switch pmax {
-       case 1:
-               tsign = math.Copysign(1, csr) * math.Copysign(1, csl) * math.Copysign(1, f)
-       case 2:
-               tsign = math.Copysign(1, snr) * math.Copysign(1, csl) * math.Copysign(1, g)
-       case 3:
-               tsign = math.Copysign(1, snr) * math.Copysign(1, snl) * math.Copysign(1, h)
-       }
-       ssmax = math.Copysign(ssmax, tsign)
-       ssmin = math.Copysign(ssmin, tsign*math.Copysign(1, f)*math.Copysign(1, h))
-       return ssmin, ssmax, snr, csr, snl, csl
-}