Mercurial > hg > svcore
view data/fft/FFTapi.cpp @ 1113:ed207f89aaef
Fix assignment of values to regions on import, in case where region model contains duplicate points
author | Chris Cannam |
---|---|
date | Fri, 03 Jul 2015 16:09:14 +0100 |
parents | e919a2b97c2a |
children | db946591a391 |
line wrap: on
line source
/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */ /* Sonic Visualiser An audio file viewer and annotation editor. Centre for Digital Music, Queen Mary, University of London. This file copyright 2006 Chris Cannam and QMUL. FFT code from Don Cross's public domain FFT implementation. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. See the file COPYING included with this distribution for more information. */ #include "FFTapi.h" #ifndef HAVE_FFTW3F #include <cmath> #include <iostream> void fft(unsigned int n, bool inverse, double *ri, double *ii, double *ro, double *io) { if (!ri || !ro || !io) return; unsigned int bits; unsigned int i, j, k, m; unsigned int blockSize, blockEnd; double tr, ti; if (n < 2) return; if (n & (n-1)) return; double angle = 2.0 * M_PI; if (inverse) angle = -angle; for (i = 0; ; ++i) { if (n & (1 << i)) { bits = i; break; } } int *table = new int[n]; for (i = 0; i < n; ++i) { m = i; for (j = k = 0; j < bits; ++j) { k = (k << 1) | (m & 1); m >>= 1; } table[i] = k; } if (ii) { for (i = 0; i < n; ++i) { ro[table[i]] = ri[i]; io[table[i]] = ii[i]; } } else { for (i = 0; i < n; ++i) { ro[table[i]] = ri[i]; io[table[i]] = 0.0; } } blockEnd = 1; for (blockSize = 2; blockSize <= n; blockSize <<= 1) { double delta = angle / (double)blockSize; double sm2 = -sin(-2 * delta); double sm1 = -sin(-delta); double cm2 = cos(-2 * delta); double cm1 = cos(-delta); double w = 2 * cm1; double ar[3], ai[3]; for (i = 0; i < n; i += blockSize) { ar[2] = cm2; ar[1] = cm1; ai[2] = sm2; ai[1] = sm1; for (j = i, m = 0; m < blockEnd; j++, m++) { ar[0] = w * ar[1] - ar[2]; ar[2] = ar[1]; ar[1] = ar[0]; ai[0] = w * ai[1] - ai[2]; ai[2] = ai[1]; ai[1] = ai[0]; k = j + blockEnd; tr = ar[0] * ro[k] - ai[0] * io[k]; ti = ar[0] * io[k] + ai[0] * ro[k]; ro[k] = ro[j] - tr; io[k] = io[j] - ti; ro[j] += tr; io[j] += ti; } } blockEnd = blockSize; } /* fftw doesn't normalise, so nor will we if (inverse) { double denom = (double)n; for (i = 0; i < n; i++) { ro[i] /= denom; io[i] /= denom; } } */ delete[] table; } struct fftf_plan_ { int size; int inverse; float *real; fftf_complex *cplx; }; fftf_plan fftf_plan_dft_r2c_1d(int n, float *in, fftf_complex *out, unsigned) { if (n < 2) return 0; if (n & (n-1)) return 0; fftf_plan_ *plan = new fftf_plan_; plan->size = n; plan->inverse = 0; plan->real = in; plan->cplx = out; return plan; } fftf_plan fftf_plan_dft_c2r_1d(int n, fftf_complex *in, float *out, unsigned) { if (n < 2) return 0; if (n & (n-1)) return 0; fftf_plan_ *plan = new fftf_plan_; plan->size = n; plan->inverse = 1; plan->real = out; plan->cplx = in; return plan; } void fftf_destroy_plan(fftf_plan p) { delete p; } void fftf_execute(const fftf_plan p) { float *real = p->real; fftf_complex *cplx = p->cplx; int n = p->size; int forward = !p->inverse; double *ri = new double[n]; double *ro = new double[n]; double *io = new double[n]; double *ii = 0; if (!forward) ii = new double[n]; if (forward) { for (int i = 0; i < n; ++i) { ri[i] = real[i]; } } else { for (int i = 0; i < n/2+1; ++i) { ri[i] = cplx[i][0]; ii[i] = cplx[i][1]; if (i > 0) { ri[n-i] = ri[i]; ii[n-i] = -ii[i]; } } } fft(n, !forward, ri, ii, ro, io); if (forward) { for (int i = 0; i < n/2+1; ++i) { cplx[i][0] = ro[i]; cplx[i][1] = io[i]; } } else { for (int i = 0; i < n; ++i) { real[i] = ro[i]; } } delete[] ri; delete[] ro; delete[] io; if (ii) delete[] ii; } #endif