Mercurial > hg > peckfft
comparison peck_fftr.c @ 0:723f588b82ac
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| author | Peter Meerwald <p.meerwald@bct-electronic.com> |
|---|---|
| date | Fri, 16 Sep 2011 12:53:08 +0200 |
| parents | |
| children | 3b31bd44a09f |
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| -1:000000000000 | 0:723f588b82ac |
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| 1 /* | |
| 2 Copyright (c) 2003-2004, Mark Borgerding | |
| 3 | |
| 4 All rights reserved. | |
| 5 | |
| 6 Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: | |
| 7 | |
| 8 * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. | |
| 9 * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. | |
| 10 * Neither the author nor the names of any contributors may be used to endorse or promote products derived from this software without specific prior written permission. | |
| 11 | |
| 12 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
| 13 */ | |
| 14 | |
| 15 #include "peck_fftr.h" | |
| 16 #include "_peck_fft_guts.h" | |
| 17 | |
| 18 struct peck_fftr_state{ | |
| 19 peck_fft_cfg substate; | |
| 20 peck_fft_cpx *tmpbuf; | |
| 21 peck_fft_cpx *super_twiddles; | |
| 22 #ifdef USE_SIMD | |
| 23 void * pad; | |
| 24 #endif | |
| 25 }; | |
| 26 | |
| 27 peck_fftr_cfg peck_fftr_alloc(int nfft, int inverse_fft, void *mem, size_t *lenmem) { | |
| 28 int i; | |
| 29 peck_fftr_cfg st = NULL; | |
| 30 size_t subsize, memneeded; | |
| 31 | |
| 32 if (nfft & 1) { | |
| 33 fprintf(stderr, "Real FFT must be even.\n"); | |
| 34 return NULL; | |
| 35 } | |
| 36 nfft >>= 1; | |
| 37 | |
| 38 peck_fft_alloc(nfft, inverse_fft, NULL, &subsize); | |
| 39 memneeded = sizeof(struct peck_fftr_state) + subsize + sizeof(peck_fft_cpx) * (nfft * 3 / 2); | |
| 40 | |
| 41 if (lenmem == NULL) { | |
| 42 st = (peck_fftr_cfg) PECK_FFT_MALLOC(memneeded); | |
| 43 } else { | |
| 44 if (*lenmem >= memneeded) | |
| 45 st = (peck_fftr_cfg) mem; | |
| 46 *lenmem = memneeded; | |
| 47 } | |
| 48 if (!st) | |
| 49 return NULL; | |
| 50 | |
| 51 st->substate = (peck_fft_cfg) (st + 1); /* just beyond peck_fftr_state struct */ | |
| 52 st->tmpbuf = (peck_fft_cpx *) (((char *) st->substate) + subsize); | |
| 53 st->super_twiddles = st->tmpbuf + nfft; | |
| 54 peck_fft_alloc(nfft, inverse_fft, st->substate, &subsize); | |
| 55 | |
| 56 for (i = 0; i < nfft/2; ++i) { | |
| 57 float phase = | |
| 58 -3.14159265359f * ((float) (i+1) / nfft + 0.5f); | |
| 59 if (inverse_fft) | |
| 60 phase *= -1; | |
| 61 kf_cexp(st->super_twiddles+i,phase); | |
| 62 } | |
| 63 return st; | |
| 64 } | |
| 65 | |
| 66 void peck_fftr(peck_fftr_cfg st, const peck_fft_scalar *timedata, peck_fft_cpx *freqdata) { | |
| 67 /* Input buffer timedata is stored row-wise */ | |
| 68 int k, ncfft; | |
| 69 peck_fft_cpx fpnk, fpk, f1k, f2k, tw, tdc; | |
| 70 | |
| 71 if (st->substate->inverse) { | |
| 72 fprintf(stderr, "peck_fft usage error: improper alloc\n"); | |
| 73 exit(EXIT_FAILURE); | |
| 74 } | |
| 75 | |
| 76 ncfft = st->substate->nfft; | |
| 77 | |
| 78 /* Perform the parallel FFT of two real signals packed in real,imag */ | |
| 79 peck_fft(st->substate, (const peck_fft_cpx*)timedata, st->tmpbuf); | |
| 80 /* The real part of the DC element of the frequency spectrum in st->tmpbuf | |
| 81 * contains the sum of the even-numbered elements of the input time sequence. | |
| 82 * The imag part is the sum of the odd-numbered elements. | |
| 83 * | |
| 84 * The sum of tdc.r and tdc.i is the sum of the input time sequence, | |
| 85 * yielding DC of the input time sequence. | |
| 86 * The difference of tdc.r - tdc.i is the sum of the input (dot product) [1,-1,1,-1,... | |
| 87 * yielding the Nyquist bin of input time sequence. | |
| 88 */ | |
| 89 | |
| 90 tdc.r = st->tmpbuf[0].r; | |
| 91 tdc.i = st->tmpbuf[0].i; | |
| 92 C_FIXDIV(tdc,2); | |
| 93 CHECK_OVERFLOW_OP(tdc.r ,+, tdc.i); | |
| 94 CHECK_OVERFLOW_OP(tdc.r ,-, tdc.i); | |
| 95 freqdata[0].r = tdc.r + tdc.i; | |
| 96 freqdata[ncfft].r = tdc.r - tdc.i; | |
| 97 #ifdef USE_SIMD | |
| 98 freqdata[ncfft].i = freqdata[0].i = _mm_set1_ps(0); | |
| 99 #else | |
| 100 freqdata[ncfft].i = freqdata[0].i = 0; | |
| 101 #endif | |
| 102 | |
| 103 for (k = 1; k <= ncfft/2; ++k) { | |
| 104 fpk = st->tmpbuf[k]; | |
| 105 fpnk.r = st->tmpbuf[ncfft-k].r; | |
| 106 fpnk.i = - st->tmpbuf[ncfft-k].i; | |
| 107 C_FIXDIV(fpk, 2); | |
| 108 C_FIXDIV(fpnk, 2); | |
| 109 | |
| 110 C_ADD(f1k, fpk, fpnk); | |
| 111 C_SUB(f2k, fpk, fpnk); | |
| 112 C_MUL(tw, f2k, st->super_twiddles[k-1]); | |
| 113 | |
| 114 freqdata[k].r = HALF_OF(f1k.r + tw.r); | |
| 115 freqdata[k].i = HALF_OF(f1k.i + tw.i); | |
| 116 freqdata[ncfft-k].r = HALF_OF(f1k.r - tw.r); | |
| 117 freqdata[ncfft-k].i = HALF_OF(tw.i - f1k.i); | |
| 118 } | |
| 119 } | |
| 120 | |
| 121 void peck_fftri(peck_fftr_cfg st,const peck_fft_cpx *freqdata,peck_fft_scalar *timedata) { | |
| 122 /* input buffer timedata is stored row-wise */ | |
| 123 int k, ncfft; | |
| 124 | |
| 125 if (st->substate->inverse == 0) { | |
| 126 fprintf (stderr, "peck_fft usage error: improper alloc\n"); | |
| 127 exit(EXIT_FAILURE); | |
| 128 } | |
| 129 | |
| 130 ncfft = st->substate->nfft; | |
| 131 | |
| 132 st->tmpbuf[0].r = freqdata[0].r + freqdata[ncfft].r; | |
| 133 st->tmpbuf[0].i = freqdata[0].r - freqdata[ncfft].r; | |
| 134 C_FIXDIV(st->tmpbuf[0], 2); | |
| 135 | |
| 136 for (k = 1; k <= ncfft / 2; ++k) { | |
| 137 peck_fft_cpx fk, fnkc, fek, fok, tmp; | |
| 138 fk = freqdata[k]; | |
| 139 fnkc.r = freqdata[ncfft - k].r; | |
| 140 fnkc.i = -freqdata[ncfft - k].i; | |
| 141 C_FIXDIV(fk , 2); | |
| 142 C_FIXDIV(fnkc , 2); | |
| 143 | |
| 144 C_ADD(fek, fk, fnkc); | |
| 145 C_SUB(tmp, fk, fnkc); | |
| 146 C_MUL(fok, tmp, st->super_twiddles[k-1]); | |
| 147 C_ADD(st->tmpbuf[k], fek, fok); | |
| 148 C_SUB(st->tmpbuf[ncfft - k], fek, fok); | |
| 149 #ifdef USE_SIMD | |
| 150 st->tmpbuf[ncfft - k].i *= _mm_set1_ps(-1.0); | |
| 151 #else | |
| 152 st->tmpbuf[ncfft - k].i *= -1; | |
| 153 #endif | |
| 154 } | |
| 155 peck_fft(st->substate, st->tmpbuf, (peck_fft_cpx *) timedata); | |
| 156 } |