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84 lines
1.9 KiB
Go
84 lines
1.9 KiB
Go
// Copyright ©2018 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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// This file must be kept in sync with array_bound_checks.go.
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//go:build !bounds
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// +build !bounds
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package fftpack
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// The types in array.go implement Fortran-like arrays for bootstrapping
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// the implementation of the FFT functions translated from FFTPACK; they
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// are column-major.
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type twoArray struct {
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jStride int
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data []float64
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}
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func newTwoArray(i, j int, data []float64) twoArray {
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if len(data) < i*j {
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panic("fourier: short data")
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}
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return twoArray{
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jStride: i,
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data: data[:i*j],
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}
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}
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func (a twoArray) at(i, j int) float64 {
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return a.data[i+a.jStride*j]
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}
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func (a twoArray) atCmplx(i, j int) complex128 {
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return complex(a.data[i+a.jStride*j], a.data[i+a.jStride*j+1])
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}
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func (a twoArray) set(i, j int, v float64) {
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a.data[i+a.jStride*j] = v
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}
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func (a twoArray) setCmplx(i, j int, v complex128) {
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a.data[i+a.jStride*j] = real(v)
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a.data[i+a.jStride*j+1] = imag(v)
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}
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func (a twoArray) add(i, j int, v float64) {
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a.data[i+a.jStride*j] += v
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}
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type threeArray struct {
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jStride, kStride int
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data []float64
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}
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func newThreeArray(i, j, k int, data []float64) threeArray {
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if len(data) < i*j*k {
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panic("fourier: short data")
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}
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return threeArray{
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jStride: i,
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kStride: i * j,
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data: data[:i*j*k],
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}
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}
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func (a threeArray) at(i, j, k int) float64 {
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return a.data[i+a.jStride*j+a.kStride*k]
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}
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func (a threeArray) atCmplx(i, j, k int) complex128 {
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return complex(a.data[i+a.jStride*j+a.kStride*k], a.data[i+a.jStride*j+a.kStride*k+1])
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}
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func (a threeArray) set(i, j, k int, v float64) {
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a.data[i+a.jStride*j+a.kStride*k] = v
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}
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func (a threeArray) setCmplx(i, j, k int, v complex128) {
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a.data[i+a.jStride*j+a.kStride*k] = real(v)
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a.data[i+a.jStride*j+a.kStride*k+1] = imag(v)
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}
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