annotate src/fftw-3.3.8/rdft/rdft2-inplace-strides.c @ 82:d0c2a83c1364

Add FFTW 3.3.8 source, and a Linux build
author Chris Cannam
date Tue, 19 Nov 2019 14:52:55 +0000
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Chris@82 1 /*
Chris@82 2 * Copyright (c) 2003, 2007-14 Matteo Frigo
Chris@82 3 * Copyright (c) 2003, 2007-14 Massachusetts Institute of Technology
Chris@82 4 *
Chris@82 5 * This program is free software; you can redistribute it and/or modify
Chris@82 6 * it under the terms of the GNU General Public License as published by
Chris@82 7 * the Free Software Foundation; either version 2 of the License, or
Chris@82 8 * (at your option) any later version.
Chris@82 9 *
Chris@82 10 * This program is distributed in the hope that it will be useful,
Chris@82 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
Chris@82 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
Chris@82 13 * GNU General Public License for more details.
Chris@82 14 *
Chris@82 15 * You should have received a copy of the GNU General Public License
Chris@82 16 * along with this program; if not, write to the Free Software
Chris@82 17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
Chris@82 18 *
Chris@82 19 */
Chris@82 20
Chris@82 21
Chris@82 22 #include "rdft/rdft.h"
Chris@82 23
Chris@82 24 /* Check if the vecsz/sz strides are consistent with the problem
Chris@82 25 being in-place for vecsz.dim[vdim], or for all dimensions
Chris@82 26 if vdim == RNK_MINFTY. We can't just use tensor_inplace_strides
Chris@82 27 because rdft transforms have the unfortunate property of
Chris@82 28 differing input and output sizes. This routine is not
Chris@82 29 exhaustive; we only return 1 for the most common case. */
Chris@82 30 int X(rdft2_inplace_strides)(const problem_rdft2 *p, int vdim)
Chris@82 31 {
Chris@82 32 INT N, Nc;
Chris@82 33 INT rs, cs;
Chris@82 34 int i;
Chris@82 35
Chris@82 36 for (i = 0; i + 1 < p->sz->rnk; ++i)
Chris@82 37 if (p->sz->dims[i].is != p->sz->dims[i].os)
Chris@82 38 return 0;
Chris@82 39
Chris@82 40 if (!FINITE_RNK(p->vecsz->rnk) || p->vecsz->rnk == 0)
Chris@82 41 return 1;
Chris@82 42 if (!FINITE_RNK(vdim)) { /* check all vector dimensions */
Chris@82 43 for (vdim = 0; vdim < p->vecsz->rnk; ++vdim)
Chris@82 44 if (!X(rdft2_inplace_strides)(p, vdim))
Chris@82 45 return 0;
Chris@82 46 return 1;
Chris@82 47 }
Chris@82 48
Chris@82 49 A(vdim < p->vecsz->rnk);
Chris@82 50 if (p->sz->rnk == 0)
Chris@82 51 return(p->vecsz->dims[vdim].is == p->vecsz->dims[vdim].os);
Chris@82 52
Chris@82 53 N = X(tensor_sz)(p->sz);
Chris@82 54 Nc = (N / p->sz->dims[p->sz->rnk-1].n) *
Chris@82 55 (p->sz->dims[p->sz->rnk-1].n/2 + 1);
Chris@82 56 X(rdft2_strides)(p->kind, p->sz->dims + p->sz->rnk - 1, &rs, &cs);
Chris@82 57
Chris@82 58 /* the factor of 2 comes from the fact that RS is the stride
Chris@82 59 of p->r0 and p->r1, which is twice as large as the strides
Chris@82 60 in the r2r case */
Chris@82 61 return(p->vecsz->dims[vdim].is == p->vecsz->dims[vdim].os
Chris@82 62 && (X(iabs)(2 * p->vecsz->dims[vdim].os)
Chris@82 63 >= X(imax)(2 * Nc * X(iabs)(cs), N * X(iabs)(rs))));
Chris@82 64 }