annotate vamp-sdk/hostext/PluginInputDomainAdapter.cpp @ 101:5c9f267c48c0

* Add optional support for FFTW through HAVE_FFTW3 flag. Off by default, and should be off in any distro packages, for licensing reasons.
author cannam
date Mon, 28 Jan 2008 12:34:39 +0000
parents c94c066a4897
children 2cb46126ef59
rev   line source
cannam@64 1 /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */
cannam@64 2
cannam@64 3 /*
cannam@64 4 Vamp
cannam@64 5
cannam@64 6 An API for audio analysis and feature extraction plugins.
cannam@64 7
cannam@64 8 Centre for Digital Music, Queen Mary, University of London.
cannam@71 9 Copyright 2006-2007 Chris Cannam and QMUL.
cannam@64 10
cannam@64 11 Permission is hereby granted, free of charge, to any person
cannam@64 12 obtaining a copy of this software and associated documentation
cannam@64 13 files (the "Software"), to deal in the Software without
cannam@64 14 restriction, including without limitation the rights to use, copy,
cannam@64 15 modify, merge, publish, distribute, sublicense, and/or sell copies
cannam@64 16 of the Software, and to permit persons to whom the Software is
cannam@64 17 furnished to do so, subject to the following conditions:
cannam@64 18
cannam@64 19 The above copyright notice and this permission notice shall be
cannam@64 20 included in all copies or substantial portions of the Software.
cannam@64 21
cannam@64 22 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
cannam@64 23 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
cannam@64 24 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
cannam@64 25 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
cannam@64 26 ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
cannam@64 27 CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
cannam@64 28 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
cannam@64 29
cannam@64 30 Except as contained in this notice, the names of the Centre for
cannam@64 31 Digital Music; Queen Mary, University of London; and Chris Cannam
cannam@64 32 shall not be used in advertising or otherwise to promote the sale,
cannam@64 33 use or other dealings in this Software without prior written
cannam@64 34 authorization.
cannam@64 35 */
cannam@64 36
cannam@64 37 #include "PluginInputDomainAdapter.h"
cannam@64 38
cannam@64 39 #include <cmath>
cannam@64 40
cannam@101 41
cannam@101 42 /**
cannam@101 43 * If you want to compile using FFTW instead of the built-in FFT
cannam@101 44 * implementation for the PluginInputDomainAdapter, define HAVE_FFTW3
cannam@101 45 * in the Makefile.
cannam@101 46 *
cannam@101 47 * Remember that FFTW is licensed under the GPL (unlike this SDK, which
cannam@101 48 * is licensed liberally in order to permit closed-source usage), so
cannam@101 49 * you should not define this symbol unless your code is also under the
cannam@101 50 * GPL. Also, parties redistributing this SDK for use in other
cannam@101 51 * programs should be careful _not_ to define this symbol in order not
cannam@101 52 * to affect the stated license of this SDK.
cannam@101 53 *
cannam@101 54 * Note: This code uses FFTW_MEASURE, and will perform badly on its
cannam@101 55 * first invocation unless the host has saved and restored FFTW wisdom
cannam@101 56 * (see the FFTW documentation).
cannam@101 57 */
cannam@101 58 #ifdef HAVE_FFTW3
cannam@101 59 #include <fftw3.h>
cannam@101 60 #endif
cannam@101 61
cannam@101 62
cannam@64 63 namespace Vamp {
cannam@64 64
cannam@64 65 namespace HostExt {
cannam@64 66
cannam@70 67 class PluginInputDomainAdapter::Impl
cannam@70 68 {
cannam@70 69 public:
cannam@70 70 Impl(Plugin *plugin, float inputSampleRate);
cannam@70 71 ~Impl();
cannam@70 72
cannam@70 73 bool initialise(size_t channels, size_t stepSize, size_t blockSize);
cannam@70 74
cannam@70 75 size_t getPreferredStepSize() const;
cannam@70 76 size_t getPreferredBlockSize() const;
cannam@70 77
cannam@70 78 FeatureSet process(const float *const *inputBuffers, RealTime timestamp);
cannam@70 79
cannam@70 80 protected:
cannam@70 81 Plugin *m_plugin;
cannam@70 82 float m_inputSampleRate;
cannam@101 83 int m_channels;
cannam@101 84 int m_blockSize;
cannam@70 85 float **m_freqbuf;
cannam@101 86
cannam@70 87 double *m_ri;
cannam@101 88 double *m_window;
cannam@101 89
cannam@101 90 #ifdef HAVE_FFTW3
cannam@101 91 fftw_plan m_plan;
cannam@101 92 fftw_complex *m_cbuf;
cannam@101 93 #else
cannam@70 94 double *m_ro;
cannam@70 95 double *m_io;
cannam@70 96 void fft(unsigned int n, bool inverse,
cannam@70 97 double *ri, double *ii, double *ro, double *io);
cannam@101 98 #endif
cannam@70 99
cannam@70 100 size_t makeBlockSizeAcceptable(size_t) const;
cannam@70 101 };
cannam@70 102
cannam@64 103 PluginInputDomainAdapter::PluginInputDomainAdapter(Plugin *plugin) :
cannam@70 104 PluginWrapper(plugin)
cannam@70 105 {
cannam@70 106 m_impl = new Impl(plugin, m_inputSampleRate);
cannam@70 107 }
cannam@70 108
cannam@70 109 PluginInputDomainAdapter::~PluginInputDomainAdapter()
cannam@70 110 {
cannam@70 111 delete m_impl;
cannam@70 112 }
cannam@70 113
cannam@70 114 bool
cannam@70 115 PluginInputDomainAdapter::initialise(size_t channels, size_t stepSize, size_t blockSize)
cannam@70 116 {
cannam@70 117 return m_impl->initialise(channels, stepSize, blockSize);
cannam@70 118 }
cannam@70 119
cannam@70 120 Plugin::InputDomain
cannam@70 121 PluginInputDomainAdapter::getInputDomain() const
cannam@70 122 {
cannam@70 123 return TimeDomain;
cannam@70 124 }
cannam@70 125
cannam@70 126 size_t
cannam@70 127 PluginInputDomainAdapter::getPreferredStepSize() const
cannam@70 128 {
cannam@70 129 return m_impl->getPreferredStepSize();
cannam@70 130 }
cannam@70 131
cannam@70 132 size_t
cannam@70 133 PluginInputDomainAdapter::getPreferredBlockSize() const
cannam@70 134 {
cannam@70 135 return m_impl->getPreferredBlockSize();
cannam@70 136 }
cannam@70 137
cannam@70 138 Plugin::FeatureSet
cannam@70 139 PluginInputDomainAdapter::process(const float *const *inputBuffers, RealTime timestamp)
cannam@70 140 {
cannam@70 141 return m_impl->process(inputBuffers, timestamp);
cannam@70 142 }
cannam@70 143
cannam@92 144 PluginInputDomainAdapter::Impl::Impl(Plugin *plugin, float inputSampleRate) :
cannam@70 145 m_plugin(plugin),
cannam@70 146 m_inputSampleRate(inputSampleRate),
cannam@64 147 m_channels(0),
cannam@64 148 m_blockSize(0),
cannam@101 149 m_freqbuf(0),
cannam@101 150 m_ri(0),
cannam@101 151 m_window(0),
cannam@101 152 #ifdef HAVE_FFTW3
cannam@101 153 m_plan(0),
cannam@101 154 m_cbuf(0)
cannam@101 155 #else
cannam@101 156 m_ro(0),
cannam@101 157 m_io(0)
cannam@101 158 #endif
cannam@64 159 {
cannam@64 160 }
cannam@64 161
cannam@70 162 PluginInputDomainAdapter::Impl::~Impl()
cannam@64 163 {
cannam@70 164 // the adapter will delete the plugin
cannam@70 165
cannam@70 166 if (m_channels > 0) {
cannam@101 167 for (int c = 0; c < m_channels; ++c) {
cannam@70 168 delete[] m_freqbuf[c];
cannam@70 169 }
cannam@70 170 delete[] m_freqbuf;
cannam@101 171 #ifdef HAVE_FFTW3
cannam@101 172 if (m_plan) {
cannam@101 173 fftw_destroy_plan(m_plan);
cannam@101 174 fftw_free(m_ri);
cannam@101 175 fftw_free(m_cbuf);
cannam@101 176 m_plan = 0;
cannam@101 177 }
cannam@101 178 #else
cannam@70 179 delete[] m_ri;
cannam@70 180 delete[] m_ro;
cannam@70 181 delete[] m_io;
cannam@101 182 #endif
cannam@101 183 delete[] m_window;
cannam@70 184 }
cannam@64 185 }
cannam@101 186
cannam@101 187 // for some visual studii apparently
cannam@101 188 #ifndef M_PI
cannam@101 189 #define M_PI 3.14159265358979232846
cannam@101 190 #endif
cannam@64 191
cannam@64 192 bool
cannam@70 193 PluginInputDomainAdapter::Impl::initialise(size_t channels, size_t stepSize, size_t blockSize)
cannam@64 194 {
cannam@64 195 if (m_plugin->getInputDomain() == TimeDomain) {
cannam@64 196
cannam@101 197 m_blockSize = int(blockSize);
cannam@101 198 m_channels = int(channels);
cannam@64 199
cannam@64 200 return m_plugin->initialise(channels, stepSize, blockSize);
cannam@64 201 }
cannam@64 202
cannam@64 203 if (blockSize < 2) {
cannam@70 204 std::cerr << "ERROR: Vamp::HostExt::PluginInputDomainAdapter::Impl::initialise: blocksize < 2 not supported" << std::endl;
cannam@64 205 return false;
cannam@64 206 }
cannam@64 207
cannam@64 208 if (blockSize & (blockSize-1)) {
cannam@70 209 std::cerr << "ERROR: Vamp::HostExt::PluginInputDomainAdapter::Impl::initialise: non-power-of-two\nblocksize " << blockSize << " not supported" << std::endl;
cannam@64 210 return false;
cannam@64 211 }
cannam@64 212
cannam@64 213 if (m_channels > 0) {
cannam@101 214 for (int c = 0; c < m_channels; ++c) {
cannam@64 215 delete[] m_freqbuf[c];
cannam@64 216 }
cannam@64 217 delete[] m_freqbuf;
cannam@101 218 #ifdef HAVE_FFTW3
cannam@101 219 if (m_plan) {
cannam@101 220 fftw_destroy_plan(m_plan);
cannam@101 221 fftw_free(m_ri);
cannam@101 222 fftw_free(m_cbuf);
cannam@101 223 m_plan = 0;
cannam@101 224 }
cannam@101 225 #else
cannam@64 226 delete[] m_ri;
cannam@64 227 delete[] m_ro;
cannam@64 228 delete[] m_io;
cannam@101 229 #endif
cannam@101 230 delete[] m_window;
cannam@64 231 }
cannam@64 232
cannam@101 233 m_blockSize = int(blockSize);
cannam@101 234 m_channels = int(channels);
cannam@64 235
cannam@64 236 m_freqbuf = new float *[m_channels];
cannam@101 237 for (int c = 0; c < m_channels; ++c) {
cannam@64 238 m_freqbuf[c] = new float[m_blockSize + 2];
cannam@64 239 }
cannam@101 240 m_window = new double[m_blockSize];
cannam@101 241
cannam@101 242 for (int i = 0; i < m_blockSize; ++i) {
cannam@101 243 // Hanning window
cannam@101 244 m_window[i] = (0.50 - 0.50 * cos((2.0 * M_PI * i) / m_blockSize));
cannam@101 245 }
cannam@101 246
cannam@101 247 #ifdef HAVE_FFTW3
cannam@101 248 m_ri = (double *)fftw_malloc(blockSize * sizeof(double));
cannam@101 249 m_cbuf = (fftw_complex *)fftw_malloc((blockSize/2 + 1) * sizeof(fftw_complex));
cannam@101 250 m_plan = fftw_plan_dft_r2c_1d(blockSize, m_ri, m_cbuf, FFTW_MEASURE);
cannam@101 251 #else
cannam@64 252 m_ri = new double[m_blockSize];
cannam@64 253 m_ro = new double[m_blockSize];
cannam@64 254 m_io = new double[m_blockSize];
cannam@101 255 #endif
cannam@64 256
cannam@64 257 return m_plugin->initialise(channels, stepSize, blockSize);
cannam@64 258 }
cannam@64 259
cannam@64 260 size_t
cannam@70 261 PluginInputDomainAdapter::Impl::getPreferredStepSize() const
cannam@64 262 {
cannam@64 263 size_t step = m_plugin->getPreferredStepSize();
cannam@64 264
cannam@64 265 if (step == 0 && (m_plugin->getInputDomain() == FrequencyDomain)) {
cannam@64 266 step = getPreferredBlockSize() / 2;
cannam@64 267 }
cannam@64 268
cannam@64 269 return step;
cannam@64 270 }
cannam@64 271
cannam@64 272 size_t
cannam@70 273 PluginInputDomainAdapter::Impl::getPreferredBlockSize() const
cannam@64 274 {
cannam@64 275 size_t block = m_plugin->getPreferredBlockSize();
cannam@64 276
cannam@64 277 if (m_plugin->getInputDomain() == FrequencyDomain) {
cannam@64 278 if (block == 0) {
cannam@64 279 block = 1024;
cannam@64 280 } else {
cannam@64 281 block = makeBlockSizeAcceptable(block);
cannam@64 282 }
cannam@64 283 }
cannam@64 284
cannam@64 285 return block;
cannam@64 286 }
cannam@64 287
cannam@64 288 size_t
cannam@70 289 PluginInputDomainAdapter::Impl::makeBlockSizeAcceptable(size_t blockSize) const
cannam@64 290 {
cannam@64 291 if (blockSize < 2) {
cannam@64 292
cannam@70 293 std::cerr << "WARNING: Vamp::HostExt::PluginInputDomainAdapter::Impl::initialise: blocksize < 2 not" << std::endl
cannam@64 294 << "supported, increasing from " << blockSize << " to 2" << std::endl;
cannam@64 295 blockSize = 2;
cannam@64 296
cannam@64 297 } else if (blockSize & (blockSize-1)) {
cannam@64 298
cannam@101 299 #ifdef HAVE_FFTW3
cannam@101 300 // not an issue with FFTW
cannam@101 301 #else
cannam@101 302
cannam@101 303 // not a power of two, can't handle that with our built-in FFT
cannam@64 304 // implementation
cannam@64 305
cannam@64 306 size_t nearest = blockSize;
cannam@64 307 size_t power = 0;
cannam@64 308 while (nearest > 1) {
cannam@64 309 nearest >>= 1;
cannam@64 310 ++power;
cannam@64 311 }
cannam@64 312 nearest = 1;
cannam@64 313 while (power) {
cannam@64 314 nearest <<= 1;
cannam@64 315 --power;
cannam@64 316 }
cannam@64 317
cannam@64 318 if (blockSize - nearest > (nearest*2) - blockSize) {
cannam@64 319 nearest = nearest*2;
cannam@64 320 }
cannam@64 321
cannam@70 322 std::cerr << "WARNING: Vamp::HostExt::PluginInputDomainAdapter::Impl::initialise: non-power-of-two\nblocksize " << blockSize << " not supported, using blocksize " << nearest << " instead" << std::endl;
cannam@64 323 blockSize = nearest;
cannam@101 324
cannam@101 325 #endif
cannam@64 326 }
cannam@64 327
cannam@64 328 return blockSize;
cannam@64 329 }
cannam@64 330
cannam@64 331 Plugin::FeatureSet
cannam@70 332 PluginInputDomainAdapter::Impl::process(const float *const *inputBuffers,
cannam@70 333 RealTime timestamp)
cannam@64 334 {
cannam@64 335 if (m_plugin->getInputDomain() == TimeDomain) {
cannam@64 336 return m_plugin->process(inputBuffers, timestamp);
cannam@64 337 }
cannam@64 338
cannam@64 339 // The timestamp supplied should be (according to the Vamp::Plugin
cannam@64 340 // spec) the time of the start of the time-domain input block.
cannam@64 341 // However, we want to pass to the plugin an FFT output calculated
cannam@64 342 // from the block of samples _centred_ on that timestamp.
cannam@64 343 //
cannam@64 344 // We have two options:
cannam@64 345 //
cannam@64 346 // 1. Buffer the input, calculating the fft of the values at the
cannam@64 347 // passed-in block minus blockSize/2 rather than starting at the
cannam@64 348 // passed-in block. So each time we call process on the plugin,
cannam@64 349 // we are passing in the same timestamp as was passed to our own
cannam@64 350 // process plugin, but not (the frequency domain representation
cannam@64 351 // of) the same set of samples. Advantages: avoids confusion in
cannam@64 352 // the host by ensuring the returned values have timestamps
cannam@64 353 // comparable with that passed in to this function (in fact this
cannam@64 354 // is pretty much essential for one-value-per-block outputs);
cannam@64 355 // consistent with hosts such as SV that deal with the
cannam@64 356 // frequency-domain transform themselves. Disadvantages: means
cannam@64 357 // making the not necessarily correct assumption that the samples
cannam@64 358 // preceding the first official block are all zero (or some other
cannam@64 359 // known value).
cannam@64 360 //
cannam@64 361 // 2. Increase the passed-in timestamps by half the blocksize. So
cannam@64 362 // when we call process, we are passing in the frequency domain
cannam@64 363 // representation of the same set of samples as passed to us, but
cannam@64 364 // with a different timestamp. Advantages: simplicity; avoids
cannam@64 365 // iffy assumption mentioned above. Disadvantages: inconsistency
cannam@64 366 // with SV in cases where stepSize != blockSize/2; potential
cannam@64 367 // confusion arising from returned timestamps being calculated
cannam@64 368 // from the adjusted input timestamps rather than the original
cannam@64 369 // ones (and inaccuracy where the returned timestamp is implied,
cannam@64 370 // as in one-value-per-block).
cannam@64 371 //
cannam@64 372 // Neither way is ideal, but I don't think either is strictly
cannam@64 373 // incorrect either. I think this is just a case where the same
cannam@64 374 // plugin can legitimately produce differing results from the same
cannam@64 375 // input data, depending on how that data is packaged.
cannam@64 376 //
cannam@64 377 // We'll go for option 2, adjusting the timestamps. Note in
cannam@64 378 // particular that this means some results can differ from those
cannam@64 379 // produced by SV.
cannam@64 380
cannam@65 381 // std::cerr << "PluginInputDomainAdapter: sampleRate " << m_inputSampleRate << ", blocksize " << m_blockSize << ", adjusting time from " << timestamp;
cannam@64 382
cannam@68 383 timestamp = timestamp + RealTime::frame2RealTime
cannam@68 384 (m_blockSize/2, int(m_inputSampleRate + 0.5));
cannam@64 385
cannam@65 386 // std::cerr << " to " << timestamp << std::endl;
cannam@64 387
cannam@101 388 for (int c = 0; c < m_channels; ++c) {
cannam@64 389
cannam@101 390 for (int i = 0; i < m_blockSize; ++i) {
cannam@101 391 m_ri[i] = double(inputBuffers[c][i]) * m_window[i];
cannam@64 392 }
cannam@64 393
cannam@101 394 for (int i = 0; i < m_blockSize/2; ++i) {
cannam@64 395 // FFT shift
cannam@64 396 double value = m_ri[i];
cannam@64 397 m_ri[i] = m_ri[i + m_blockSize/2];
cannam@64 398 m_ri[i + m_blockSize/2] = value;
cannam@64 399 }
cannam@64 400
cannam@101 401 #ifdef HAVE_FFTW3
cannam@101 402
cannam@101 403 fftw_execute(m_plan);
cannam@101 404
cannam@101 405 for (int i = 0; i <= m_blockSize/2; ++i) {
cannam@101 406 m_freqbuf[c][i * 2] = float(m_cbuf[i][0]);
cannam@101 407 m_freqbuf[c][i * 2 + 1] = float(m_cbuf[i][1]);
cannam@101 408 }
cannam@101 409
cannam@101 410 #else
cannam@101 411
cannam@64 412 fft(m_blockSize, false, m_ri, 0, m_ro, m_io);
cannam@64 413
cannam@101 414 for (int i = 0; i <= m_blockSize/2; ++i) {
cannam@101 415 m_freqbuf[c][i * 2] = float(m_ro[i]);
cannam@101 416 m_freqbuf[c][i * 2 + 1] = float(m_io[i]);
cannam@64 417 }
cannam@101 418
cannam@101 419 #endif
cannam@64 420 }
cannam@64 421
cannam@64 422 return m_plugin->process(m_freqbuf, timestamp);
cannam@64 423 }
cannam@64 424
cannam@101 425 #ifndef HAVE_FFTW3
cannam@101 426
cannam@64 427 void
cannam@70 428 PluginInputDomainAdapter::Impl::fft(unsigned int n, bool inverse,
cannam@70 429 double *ri, double *ii, double *ro, double *io)
cannam@64 430 {
cannam@64 431 if (!ri || !ro || !io) return;
cannam@64 432
cannam@64 433 unsigned int bits;
cannam@64 434 unsigned int i, j, k, m;
cannam@64 435 unsigned int blockSize, blockEnd;
cannam@64 436
cannam@64 437 double tr, ti;
cannam@64 438
cannam@64 439 if (n < 2) return;
cannam@64 440 if (n & (n-1)) return;
cannam@64 441
cannam@64 442 double angle = 2.0 * M_PI;
cannam@64 443 if (inverse) angle = -angle;
cannam@64 444
cannam@64 445 for (i = 0; ; ++i) {
cannam@64 446 if (n & (1 << i)) {
cannam@64 447 bits = i;
cannam@64 448 break;
cannam@64 449 }
cannam@64 450 }
cannam@64 451
cannam@64 452 static unsigned int tableSize = 0;
cannam@64 453 static int *table = 0;
cannam@64 454
cannam@64 455 if (tableSize != n) {
cannam@64 456
cannam@64 457 delete[] table;
cannam@64 458
cannam@64 459 table = new int[n];
cannam@64 460
cannam@64 461 for (i = 0; i < n; ++i) {
cannam@64 462
cannam@64 463 m = i;
cannam@64 464
cannam@64 465 for (j = k = 0; j < bits; ++j) {
cannam@64 466 k = (k << 1) | (m & 1);
cannam@64 467 m >>= 1;
cannam@64 468 }
cannam@64 469
cannam@64 470 table[i] = k;
cannam@64 471 }
cannam@64 472
cannam@64 473 tableSize = n;
cannam@64 474 }
cannam@64 475
cannam@64 476 if (ii) {
cannam@64 477 for (i = 0; i < n; ++i) {
cannam@64 478 ro[table[i]] = ri[i];
cannam@64 479 io[table[i]] = ii[i];
cannam@64 480 }
cannam@64 481 } else {
cannam@64 482 for (i = 0; i < n; ++i) {
cannam@64 483 ro[table[i]] = ri[i];
cannam@64 484 io[table[i]] = 0.0;
cannam@64 485 }
cannam@64 486 }
cannam@64 487
cannam@64 488 blockEnd = 1;
cannam@64 489
cannam@64 490 for (blockSize = 2; blockSize <= n; blockSize <<= 1) {
cannam@64 491
cannam@64 492 double delta = angle / (double)blockSize;
cannam@64 493 double sm2 = -sin(-2 * delta);
cannam@64 494 double sm1 = -sin(-delta);
cannam@64 495 double cm2 = cos(-2 * delta);
cannam@64 496 double cm1 = cos(-delta);
cannam@64 497 double w = 2 * cm1;
cannam@64 498 double ar[3], ai[3];
cannam@64 499
cannam@64 500 for (i = 0; i < n; i += blockSize) {
cannam@64 501
cannam@64 502 ar[2] = cm2;
cannam@64 503 ar[1] = cm1;
cannam@64 504
cannam@64 505 ai[2] = sm2;
cannam@64 506 ai[1] = sm1;
cannam@64 507
cannam@64 508 for (j = i, m = 0; m < blockEnd; j++, m++) {
cannam@64 509
cannam@64 510 ar[0] = w * ar[1] - ar[2];
cannam@64 511 ar[2] = ar[1];
cannam@64 512 ar[1] = ar[0];
cannam@64 513
cannam@64 514 ai[0] = w * ai[1] - ai[2];
cannam@64 515 ai[2] = ai[1];
cannam@64 516 ai[1] = ai[0];
cannam@64 517
cannam@64 518 k = j + blockEnd;
cannam@64 519 tr = ar[0] * ro[k] - ai[0] * io[k];
cannam@64 520 ti = ar[0] * io[k] + ai[0] * ro[k];
cannam@64 521
cannam@64 522 ro[k] = ro[j] - tr;
cannam@64 523 io[k] = io[j] - ti;
cannam@64 524
cannam@64 525 ro[j] += tr;
cannam@64 526 io[j] += ti;
cannam@64 527 }
cannam@64 528 }
cannam@64 529
cannam@64 530 blockEnd = blockSize;
cannam@64 531 }
cannam@64 532
cannam@64 533 if (inverse) {
cannam@64 534
cannam@64 535 double denom = (double)n;
cannam@64 536
cannam@64 537 for (i = 0; i < n; i++) {
cannam@64 538 ro[i] /= denom;
cannam@64 539 io[i] /= denom;
cannam@64 540 }
cannam@64 541 }
cannam@64 542 }
cannam@64 543
cannam@101 544 #endif
cannam@101 545
cannam@64 546 }
cannam@64 547
cannam@64 548 }
cannam@64 549