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5f0141ca4c
Changes made in dsp/fourier/internal/fftpack break the formatting used there, so these are reverted. There will be complaints in CI. [git-generate] gofmt -w . go generate gonum.org/v1/gonum/blas go generate gonum.org/v1/gonum/blas/gonum go generate gonum.org/v1/gonum/unit go generate gonum.org/v1/gonum/unit/constant go generate gonum.org/v1/gonum/graph/formats/dot go generate gonum.org/v1/gonum/graph/formats/rdf go generate gonum.org/v1/gonum/stat/card git checkout -- dsp/fourier/internal/fftpack
181 lines
2.8 KiB
Go
181 lines
2.8 KiB
Go
// Copyright ©2020 The Gonum Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package c128
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import (
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"math"
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"math/cmplx"
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)
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// Add is
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//
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// for i, v := range s {
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// dst[i] += v
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// }
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func Add(dst, s []complex128) {
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for i, v := range s {
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dst[i] += v
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}
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}
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// AddConst is
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//
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// for i := range x {
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// x[i] += alpha
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// }
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func AddConst(alpha complex128, x []complex128) {
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for i := range x {
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x[i] += alpha
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}
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}
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// CumSum is
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//
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// if len(s) == 0 {
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// return dst
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// }
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// dst[0] = s[0]
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// for i, v := range s[1:] {
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// dst[i+1] = dst[i] + v
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// }
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// return dst
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func CumSum(dst, s []complex128) []complex128 {
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if len(s) == 0 {
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return dst
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}
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dst[0] = s[0]
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for i, v := range s[1:] {
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dst[i+1] = dst[i] + v
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}
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return dst
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}
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// CumProd is
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//
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// if len(s) == 0 {
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// return dst
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// }
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// dst[0] = s[0]
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// for i, v := range s[1:] {
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// dst[i+1] = dst[i] * v
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// }
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// return dst
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func CumProd(dst, s []complex128) []complex128 {
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if len(s) == 0 {
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return dst
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}
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dst[0] = s[0]
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for i, v := range s[1:] {
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dst[i+1] = dst[i] * v
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}
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return dst
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}
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// Div is
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//
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// for i, v := range s {
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// dst[i] /= v
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// }
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func Div(dst, s []complex128) {
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for i, v := range s {
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dst[i] /= v
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}
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}
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// DivTo is
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//
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// for i, v := range s {
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// dst[i] = v / t[i]
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// }
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// return dst
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func DivTo(dst, s, t []complex128) []complex128 {
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for i, v := range s {
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dst[i] = v / t[i]
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}
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return dst
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}
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// DotUnitary is
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//
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// for i, v := range x {
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// sum += cmplx.Conj(v) * y[i]
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// }
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// return sum
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func DotUnitary(x, y []complex128) (sum complex128) {
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for i, v := range x {
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sum += cmplx.Conj(v) * y[i]
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}
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return sum
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}
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// L2DistanceUnitary returns the L2-norm of x-y.
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func L2DistanceUnitary(x, y []complex128) (norm float64) {
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var scale float64
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sumSquares := 1.0
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for i, v := range x {
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v -= y[i]
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if v == 0 {
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continue
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}
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absxi := cmplx.Abs(v)
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if math.IsNaN(absxi) {
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return math.NaN()
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}
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if scale < absxi {
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s := scale / absxi
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sumSquares = 1 + sumSquares*s*s
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scale = absxi
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} else {
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s := absxi / scale
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sumSquares += s * s
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}
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}
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if math.IsInf(scale, 1) {
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return math.Inf(1)
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}
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return scale * math.Sqrt(sumSquares)
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}
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// L2NormUnitary returns the L2-norm of x.
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func L2NormUnitary(x []complex128) (norm float64) {
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var scale float64
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sumSquares := 1.0
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for _, v := range x {
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if v == 0 {
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continue
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}
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absxi := cmplx.Abs(v)
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if math.IsNaN(absxi) {
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return math.NaN()
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}
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if scale < absxi {
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s := scale / absxi
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sumSquares = 1 + sumSquares*s*s
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scale = absxi
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} else {
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s := absxi / scale
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sumSquares += s * s
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}
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}
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if math.IsInf(scale, 1) {
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return math.Inf(1)
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}
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return scale * math.Sqrt(sumSquares)
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}
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// Sum is
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//
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// var sum complex128
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// for i := range x {
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// sum += x[i]
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// }
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func Sum(x []complex128) complex128 {
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var sum complex128
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for _, v := range x {
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sum += v
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}
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return sum
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}
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