mirror of
https://github.com/tildearrow/furnace.git
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82 lines
2.3 KiB
C
82 lines
2.3 KiB
C
/*
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* Copyright (c) 2003, 2007-14 Matteo Frigo
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* Copyright (c) 2003, 2007-14 Massachusetts Institute of Technology
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*/
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/* routines shared by the various buffered solvers */
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#include "kernel/ifftw.h"
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#define DEFAULT_MAXNBUF ((INT)256)
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/* approx. 512KB of buffers for complex data */
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#define MAXBUFSZ (256 * 1024 / (INT)(sizeof(R)))
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INT X(nbuf)(INT n, INT vl, INT maxnbuf)
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{
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INT i, nbuf, lb;
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if (!maxnbuf)
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maxnbuf = DEFAULT_MAXNBUF;
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nbuf = X(imin)(maxnbuf,
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X(imin)(vl, X(imax)((INT)1, MAXBUFSZ / n)));
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/*
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* Look for a buffer number (not too small) that divides the
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* vector length, in order that we only need one child plan:
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*/
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lb = X(imax)(1, nbuf / 4);
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for (i = nbuf; i >= lb; --i)
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if (vl % i == 0)
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return i;
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/* whatever... */
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return nbuf;
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}
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#define SKEW 6 /* need to be even for SIMD */
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#define SKEWMOD 8
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INT X(bufdist)(INT n, INT vl)
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{
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if (vl == 1)
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return n;
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else
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/* return smallest X such that X >= N and X == SKEW (mod SKEWMOD) */
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return n + X(modulo)(SKEW - n, SKEWMOD);
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}
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int X(toobig)(INT n)
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{
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return n > MAXBUFSZ;
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}
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/* TRUE if there exists i < which such that maxnbuf[i] and
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maxnbuf[which] yield the same value, in which case we canonicalize
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on the minimum value */
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int X(nbuf_redundant)(INT n, INT vl, size_t which,
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const INT *maxnbuf, size_t nmaxnbuf)
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{
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size_t i;
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(void)nmaxnbuf; /* UNUSED */
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for (i = 0; i < which; ++i)
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if (X(nbuf)(n, vl, maxnbuf[i]) == X(nbuf)(n, vl, maxnbuf[which]))
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return 1;
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return 0;
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}
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