/*

 * Copyright (c) 2003, 2007-14 Matteo Frigo

 * Copyright (c) 2003, 2007-14 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

 *

 */

#include "rdft/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))));

}