94 lines
2.8 KiB
C
94 lines
2.8 KiB
C
/*=============================================================================
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This file is part of FLINT.
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FLINT 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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FLINT 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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You should have received a copy of the GNU General Public License
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along with FLINT; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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=============================================================================*/
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/******************************************************************************
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Copyright (C) 2008, 2009 William Hart
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Copyright (C) 2009 Thomas Boothby
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******************************************************************************/
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#define ulong ulongxx /* interferes with standard libraries */
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#include <math.h>
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#undef ulong
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#include <gmp.h>
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#include "flint.h"
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#include "ulong_extras.h"
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mp_limb_t n_factor_power235(ulong * exp, mp_limb_t n)
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{
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static char mod63[63] = {7,7,4,0,5,4,0,5,6,5,4,4,0,4,4,0,5,4,5,4,4,0,
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5,4,0,5,4,6,7,4,0,4,4,0,4,6,7,5,4,0,4,4,0,5,
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4,4,5,4,0,5,4,0,4,4,4,6,4,0,5,4,0,4,6};
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static char mod61[61] = {7,7,0,3,1,1,0,0,2,3,0,6,1,5,5,1,1,0,0,1,3,4,
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1,2,2,1,0,3,2,4,0,0,4,2,3,0,1,2,2,1,4,3,1,0,
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0,1,1,5,5,1,6,0,3,2,0,0,1,1,3,0,7};
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static char mod44[44] = {7,7,0,2,3,3,0,2,2,3,0,6,7,2,0,2,3,2,0,2,3,6,
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0,6,2,3,0,2,2,2,0,2,6,7,0,2,3,3,0,2,2,2,0,6};
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static char mod31[31] = {7,7,3,0,3,5,4,1,3,1,1,0,0,0,1,2,3,0,1,1,1,0,
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0,2,0,5,4,2,1,2,6};
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char t;
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t = mod31[n%31];
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if (!t) return UWORD(0);
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t &= mod44[n%44];
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if (!t) return UWORD(0);
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t &= mod61[n%61];
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if (!t) return UWORD(0);
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t&= mod63[n%63];
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if (t & 1)
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{
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double x = sqrt((double) n);
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mp_limb_t y = (mp_limb_t) (x + 0.5);
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if (n == n_pow(y, 2))
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{
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*exp = 2;
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return y;
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}
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}
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if (t & 2)
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{
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double x = pow((double) n, 1.0 / 3.0);
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mp_limb_t y = (mp_limb_t) (x + 0.5);
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if (n == n_pow(y, 3))
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{
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*exp = 3;
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return y;
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}
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}
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if (t & 4)
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{
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double x = pow((double) n, 1.0 / 5.0);
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mp_limb_t y = (mp_limb_t) (x + 0.5);
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if (n == n_pow(y, 5))
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{
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*exp = 5;
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return y;
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}
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}
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return UWORD(0);
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}
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