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/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */
/*
QM DSP Library
Centre for Digital Music, Queen Mary, University of London.
*/
#include "FFT.h"
#include "maths/MathUtilities.h"
#include "kiss_fft.h"
#include "kiss_fftr.h"
#include <cmath>
#include <iostream>
#include <stdexcept>
class FFT::D
{
public:
D(int n) : m_n(n) {
m_planf = kiss_fft_alloc(m_n, 0, NULL, NULL);
m_plani = kiss_fft_alloc(m_n, 1, NULL, NULL);
m_kin = new kiss_fft_cpx[m_n];
m_kout = new kiss_fft_cpx[m_n];
}
~D() {
kiss_fft_free(m_planf);
kiss_fft_free(m_plani);
delete[] m_kin;
delete[] m_kout;
}
void process(bool inverse,
const double *ri,
const double *ii,
double *ro,
double *io) {
for (int i = 0; i < m_n; ++i) {
m_kin[i].r = ri[i];
m_kin[i].i = (ii ? ii[i] : 0.0);
}
if (!inverse) {
kiss_fft(m_planf, m_kin, m_kout);
for (int i = 0; i < m_n; ++i) {
ro[i] = m_kout[i].r;
io[i] = m_kout[i].i;
}
} else {
kiss_fft(m_plani, m_kin, m_kout);
double scale = 1.0 / m_n;
for (int i = 0; i < m_n; ++i) {
ro[i] = m_kout[i].r * scale;
io[i] = m_kout[i].i * scale;
}
}
}
private:
int m_n;
kiss_fft_cfg m_planf;
kiss_fft_cfg m_plani;
kiss_fft_cpx *m_kin;
kiss_fft_cpx *m_kout;
};
FFT::FFT(int n) :
m_d(new D(n))
{
}
FFT::~FFT()
{
delete m_d;
}
void
FFT::process(bool inverse,
const double *p_lpRealIn, const double *p_lpImagIn,
double *p_lpRealOut, double *p_lpImagOut)
{
m_d->process(inverse,
p_lpRealIn, p_lpImagIn,
p_lpRealOut, p_lpImagOut);
}
class FFTReal::D
{
public:
D(int n) : m_n(n) {
if (n % 2) {
throw std::invalid_argument
("nsamples must be even in FFTReal constructor");
}
m_planf = kiss_fftr_alloc(m_n, 0, NULL, NULL);
m_plani = kiss_fftr_alloc(m_n, 1, NULL, NULL);
m_c = new kiss_fft_cpx[m_n];
}
~D() {
kiss_fftr_free(m_planf);
kiss_fftr_free(m_plani);
delete[] m_c;
}
void forward(const double *ri, double *ro, double *io) {
kiss_fftr(m_planf, ri, m_c);
for (int i = 0; i <= m_n/2; ++i) {
ro[i] = m_c[i].r;
io[i] = m_c[i].i;
}
for (int i = 0; i + 1 < m_n/2; ++i) {
ro[m_n - i - 1] = ro[i + 1];
io[m_n - i - 1] = -io[i + 1];
}
}
void forwardMagnitude(const double *ri, double *mo) {
double *io = new double[m_n];
forward(ri, mo, io);
for (int i = 0; i < m_n; ++i) {
mo[i] = sqrt(mo[i] * mo[i] + io[i] * io[i]);
}
delete[] io;
}
void inverse(const double *ri, const double *ii, double *ro) {
// kiss_fftr.h says
// "input freqdata has nfft/2+1 complex points"
for (int i = 0; i < m_n/2 + 1; ++i) {
m_c[i].r = ri[i];
m_c[i].i = ii[i];
}
kiss_fftri(m_plani, m_c, ro);
double scale = 1.0 / m_n;
for (int i = 0; i < m_n; ++i) {
ro[i] *= scale;
}
}
private:
int m_n;
kiss_fftr_cfg m_planf;
kiss_fftr_cfg m_plani;
kiss_fft_cpx *m_c;
};
FFTReal::FFTReal(int n) :
m_d(new D(n))
{
}
FFTReal::~FFTReal()
{
delete m_d;
}
void
FFTReal::forward(const double *ri, double *ro, double *io)
{
m_d->forward(ri, ro, io);
}
void
FFTReal::forwardMagnitude(const double *ri, double *mo)
{
m_d->forwardMagnitude(ri, mo);
}
void
FFTReal::inverse(const double *ri, const double *ii, double *ro)
{
m_d->inverse(ri, ii, ro);
}
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