/*
* 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
*
*/
/* routines shared by the various buffered solvers */
#include "ifftw.h"
#define DEFAULT_MAXNBUF ((INT)256)
/* approx. 512KB of buffers for complex data */
#define MAXBUFSZ (256 * 1024 / (INT)(sizeof(R)))
INT X(nbuf)(INT n, INT vl, INT maxnbuf)
{
INT i, nbuf, lb;
if (!maxnbuf)
maxnbuf = DEFAULT_MAXNBUF;
nbuf = X(imin)(maxnbuf,
X(imin)(vl, X(imax)((INT)1, MAXBUFSZ / n)));
/*
* Look for a buffer number (not too small) that divides the
* vector length, in order that we only need one child plan:
*/
lb = X(imax)(1, nbuf / 4);
for (i = nbuf; i >= lb; --i)
if (vl % i == 0)
return i;
/* whatever... */
return nbuf;
}
#define SKEW 6 /* need to be even for SIMD */
#define SKEWMOD 8
INT X(bufdist)(INT n, INT vl)
{
if (vl == 1)
return n;
else
/* return smallest X such that X >= N and X == SKEW (mod SKEWMOD) */
return n + X(modulo)(SKEW - n, SKEWMOD);
}
int X(toobig)(INT n)
{
return n > MAXBUFSZ;
}
/* TRUE if there exists i < which such that maxnbuf[i] and
maxnbuf[which] yield the same value, in which case we canonicalize
on the minimum value */
int X(nbuf_redundant)(INT n, INT vl, int which,
const INT *maxnbuf, int nmaxnbuf)
{
int i;
for (i = 0; i < which; ++i)
if (X(nbuf)(n, vl, maxnbuf[i]) == X(nbuf)(n, vl, maxnbuf[which]))
return 1;
return 0;
}