90 lines
2.6 KiB
C
90 lines
2.6 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) 2009 William Hart
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Copyright (C) 2010 Sebastian Pancratz
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******************************************************************************/
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#include <limits.h>
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#include <gmp.h>
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#include "flint.h"
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#include "fmpz.h"
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#include "ulong_extras.h"
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mp_limb_t n_randtest_bits(flint_rand_t state, int bits)
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{
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mp_limb_t m;
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mp_limb_t n;
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m = n_randlimb(state);
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if (m & UWORD(7))
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{
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n = n_randbits(state, bits);
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}
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else
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{
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m >>= 3;
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switch (m & UWORD(7))
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{
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case 0: n = 0; break;
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case 1: n = 1; break;
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case 2: n = COEFF_MAX; break;
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case 3: n = WORD_MAX; break;
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case 4: n = UWORD_MAX; break;
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case 5: n = (UWORD(1)<<n_randint(state, FLINT_BITS))
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- (UWORD(1)<<n_randint(state, FLINT_BITS));
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break;
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case 6: n = (UWORD(1)<<n_randint(state, FLINT_BITS));
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break;
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case 7: n = -(UWORD(1)<<n_randint(state, FLINT_BITS));
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break;
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default: n = 0;
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}
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if (bits < FLINT_BITS)
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n &= ((UWORD(1)<<bits) - UWORD(1)); /* mask it off */
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if (bits) /* set most significant bit */
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n |= (UWORD(1)<<(bits - 1));
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else
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n = 0;
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}
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return n;
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}
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mp_limb_t n_randtest(flint_rand_t state)
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{
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return n_randtest_bits(state, n_randint(state, FLINT_BITS + 1));
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}
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mp_limb_t n_randtest_not_zero(flint_rand_t state)
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{
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mp_limb_t n;
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while ((n = n_randtest(state)) == 0) ;
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return n;
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}
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