/*
* Copyright (c) 2003, 2007-11 Matteo Frigo
* Copyright (c) 2003, 2007-11 Massachusetts Institute of Technology
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include "rdft.h"
/* Check if the vecsz/sz strides are consistent with the problem
being in-place for vecsz.dim[vdim], or for all dimensions
if vdim == RNK_MINFTY. We can't just use tensor_inplace_strides
because rdft transforms have the unfortunate property of
differing input and output sizes. This routine is not
exhaustive; we only return 1 for the most common case. */
int X(rdft2_inplace_strides)(const problem_rdft2 *p, int vdim)
{
INT N, Nc;
INT rs, cs;
int i;
for (i = 0; i + 1 < p->sz->rnk; ++i)
if (p->sz->dims[i].is != p->sz->dims[i].os)
return 0;
if (!FINITE_RNK(p->vecsz->rnk) || p->vecsz->rnk == 0)
return 1;
if (!FINITE_RNK(vdim)) { /* check all vector dimensions */
for (vdim = 0; vdim < p->vecsz->rnk; ++vdim)
if (!X(rdft2_inplace_strides)(p, vdim))
return 0;
return 1;
}
A(vdim < p->vecsz->rnk);
if (p->sz->rnk == 0)
return(p->vecsz->dims[vdim].is == p->vecsz->dims[vdim].os);
N = X(tensor_sz)(p->sz);
Nc = (N / p->sz->dims[p->sz->rnk-1].n) *
(p->sz->dims[p->sz->rnk-1].n/2 + 1);
X(rdft2_strides)(p->kind, p->sz->dims + p->sz->rnk - 1, &rs, &cs);
/* the factor of 2 comes from the fact that RS is the stride
of p->r0 and p->r1, which is twice as large as the strides
in the r2r case */
return(p->vecsz->dims[vdim].is == p->vecsz->dims[vdim].os
&& (X(iabs)(2 * p->vecsz->dims[vdim].os)
>= X(imax)(2 * Nc * X(iabs)(cs), N * X(iabs)(rs))));
}