453 lines
14 KiB
C
453 lines
14 KiB
C
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/*=============================================================================
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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) 2006, 2011 William Hart
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******************************************************************************/
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#define ulong ulongxx /* interferes with system includes */
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#include <stdlib.h>
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#include <stdio.h>
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#undef ulong
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#define ulong mp_limb_t
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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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#include "qsieve.h"
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#include "fmpz.h"
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void balance4(qs_t qs_inf, mp_limb_t * A_ind,
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prime_t * factor_base, slong min, slong fact, slong span, mp_limb_t target)
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{
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slong i, j;
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mp_limb_t prod = factor_base[A_ind[0]].p * factor_base[A_ind[1]].p;
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i = fact;
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j = i + 1;
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while (j < min + span)
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{
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while (j < min + span)
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{
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if (prod*factor_base[i].p*factor_base[j].p >= target/P_GOODNESS)
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break;
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j++;
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}
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i++;
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j = i + 1;
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}
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A_ind[2] = i;
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A_ind[3] = j;
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}
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void balance5(qs_t qs_inf, mp_limb_t * A_ind,
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prime_t * factor_base, slong min, slong high, slong span, mp_limb_t target)
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{
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slong i, j;
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mp_limb_t prod = factor_base[A_ind[0]].p * factor_base[A_ind[1]].p
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* factor_base[A_ind[2]].p;
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i = A_ind[2] + 1;
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j = i + 1;
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while (j < min + span)
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{
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while (j < min + span)
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{
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if (prod*factor_base[i].p*factor_base[j].p >= target/P_GOODNESS)
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break;
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j++;
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}
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i++;
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j = i + 1;
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}
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A_ind[3] = i;
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A_ind[4] = j;
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}
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void try_compute_A(qs_t qs_inf)
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{
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slong min = qs_inf->min;
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slong span = qs_inf->span;
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slong fact = qs_inf->fact;
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slong mid = qs_inf->mid;
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slong high = qs_inf->high;
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slong s = qs_inf->s;
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mp_limb_t * A_ind = qs_inf->A_ind;
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mp_limb_t target = qs_inf->target_A;
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prime_t * factor_base = qs_inf->factor_base;
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slong i, j;
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mp_limb_t prod;
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if (qs_inf->A == 0) /* this is our first poly */
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{
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A_ind[0] = min;
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/* try to pick prime factors of A whose product is not much smaller than target_A */
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switch (s) /* we can only have up to 5 factors in A for small factorisations */
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{
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case 1:
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break;
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case 2:
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prod = factor_base[A_ind[0]].p;
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i = A_ind[0] + 1;
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while (prod*factor_base[i].p < target/P_GOODNESS2 && i + 1 < min + span) i++;
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A_ind[1] = i;
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break;
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case 3:
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A_ind[1] = mid;
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prod = factor_base[A_ind[0]].p * factor_base[A_ind[1]].p;
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i = A_ind[1] + 1;
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while (prod*factor_base[i].p < target/P_GOODNESS && i + 1 < min + span) i++;
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A_ind[2] = i;
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break;
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case 4:
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A_ind[1] = A_ind[0] + 1;
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balance4(qs_inf, A_ind, factor_base, min, fact, span, target);
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break;
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case 5:
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A_ind[1] = A_ind[0] + 1;
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A_ind[2] = mid;
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balance5(qs_inf, A_ind, factor_base, min, high, span, target);
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break;
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}
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} else /* update to the next poly */
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{
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switch (s)
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{
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case 1:
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if (A_ind[0] + 1 < min + span)
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A_ind[0]++;
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else
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goto out_of_polys;
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break;
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case 2:
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i = A_ind[0];
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j = A_ind[1] + 1;
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if (j < min + span && factor_base[i].p * factor_base[j].p < P_GOODNESS2*target)
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A_ind[1] = j; /* we can just increment second index */
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else /* must increment first index */
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{
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i++;
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if (i < fact) /* find first appropriate second index */
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{
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A_ind[0] = i;
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prod = factor_base[A_ind[0]].p;
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i = A_ind[0] + 1;
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while (prod*factor_base[i].p < target/P_GOODNESS && i + 1 < min + span) i++;
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A_ind[1] = i;
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} else
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goto out_of_polys;
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}
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break;
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case 3:
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prod = factor_base[A_ind[0]].p * factor_base[A_ind[1]].p;
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j = A_ind[2] + 1;
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if (j < min + span && prod * factor_base[j].p < P_GOODNESS*target)
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A_ind[2] = j; /* increment third index */
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else
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{
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A_ind[1]++; /* increment second index */
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i = A_ind[1] + 1;
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prod = factor_base[A_ind[0]].p * factor_base[A_ind[1]].p;
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if (i < min + span && prod * factor_base[i].p < P_GOODNESS*target)
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{
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while (prod*factor_base[i].p < target/P_GOODNESS && i + 1 < min + span) i++;
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A_ind[2] = i;
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} else /* must increment first index */
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{
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A_ind[0]++;
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if (A_ind[0] < mid)
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{
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A_ind[1] = mid;
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prod = factor_base[A_ind[0]].p * factor_base[A_ind[1]].p;
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i = A_ind[1] + 1;
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while (prod*factor_base[i].p < target/P_GOODNESS && i + 1 < min + span) i++;
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A_ind[2] = i;
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} else
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goto out_of_polys;
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}
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}
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break;
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case 4:
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prod = factor_base[A_ind[0]].p * factor_base[A_ind[1]].p * factor_base[A_ind[2]].p;
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j = A_ind[3] + 1;
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if (j < min + span && prod * factor_base[j].p < P_GOODNESS*target)
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A_ind[3] = j; /* increment fourth index */
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else
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{
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A_ind[2]++; /* increment third index */
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i = A_ind[2] + 1;
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prod = factor_base[A_ind[0]].p * factor_base[A_ind[1]].p * factor_base[A_ind[2]].p;
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if (i < min + span && prod * factor_base[i].p < P_GOODNESS*target)
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{
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while (prod*factor_base[i].p < target/P_GOODNESS && i + 1 < min + span) i++;
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A_ind[3] = i;
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} else
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{
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A_ind[1]++; /* increment second index */
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if (A_ind[1] < fact)
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{
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balance4(qs_inf, A_ind, factor_base, min, fact, span, target);
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} else
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{
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A_ind[0]++; /* increment first factor */
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A_ind[1] = A_ind[0] + 1;
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if (A_ind[1] < fact)
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{
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balance4(qs_inf, A_ind, factor_base, min, fact, span, target);
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} else
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goto out_of_polys;
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}
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}
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}
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break;
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case 5:
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prod = factor_base[A_ind[0]].p * factor_base[A_ind[1]].p * factor_base[A_ind[2]].p * factor_base[A_ind[3]].p;
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j = A_ind[4] + 1;
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if (j < min + span && prod * factor_base[j].p < P_GOODNESS*target)
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A_ind[4] = j; /* increment fifth index */
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else
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{
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A_ind[3]++; /* increment fourth index */
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i = A_ind[3] + 1;
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prod = factor_base[A_ind[0]].p * factor_base[A_ind[1]].p * factor_base[A_ind[2]].p * factor_base[A_ind[3]].p;
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if (i < min + span && prod * factor_base[i].p < P_GOODNESS*target)
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{
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while (prod*factor_base[i].p < target/P_GOODNESS && i + 1 < min + span) i++;
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A_ind[4] = i;
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} else
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{
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A_ind[2]++; /* increment third index */
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if (A_ind[2] < high)
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{
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balance5(qs_inf, A_ind, factor_base, min, high, span, target);
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} else
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{
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A_ind[1]++; /* increment second index */
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if (A_ind[1] < high)
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{
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A_ind[2] = mid;
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balance5(qs_inf, A_ind, factor_base, min, high, span, target);
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} else
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{
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A_ind[0]++; /* increment first factor */
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A_ind[1] = A_ind[0] + 1;
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if (A_ind[1] < mid)
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{
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A_ind[2] = mid;
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balance5(qs_inf, A_ind, factor_base, min, high, span, target);
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} else
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goto out_of_polys;
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}
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}
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}
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}
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break;
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}
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}
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qs_inf->A = 1;
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for (i = 0; i < s; i++)
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qs_inf->A *= factor_base[A_ind[i]].p;
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return;
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out_of_polys:
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flint_printf("Out of polynomials, s = %wd\n", qs_inf->s);
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abort();
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}
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void qsieve_ll_compute_A(qs_t qs_inf)
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{
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slong i;
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do
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{
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try_compute_A(qs_inf);
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} while (((qs_inf->A > P_GOODNESS * qs_inf->target_A
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|| qs_inf->A < qs_inf->target_A / P_GOODNESS) && qs_inf->s > 2)
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|| (((qs_inf->A > P_GOODNESS2 * qs_inf->target_A
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|| qs_inf->A < qs_inf->target_A / P_GOODNESS2) && qs_inf->s == 2)));
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#if QS_DEBUG > 1
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flint_printf("A = %wd, target A = %wd\n", qs_inf->A, qs_inf->target_A);
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#endif
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for (i = 0; i < qs_inf->s; i++)
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{
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mp_limb_t p = qs_inf->factor_base[qs_inf->A_ind[i]].p;
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qs_inf->inv_p2[i] = n_preinvert_limb(p*p);
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}
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}
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void qsieve_ll_compute_B_terms(qs_t qs_inf)
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{
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slong s = qs_inf->s;
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mp_limb_t * A_ind = qs_inf->A_ind;
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mp_limb_t * A_modp = qs_inf->A_modp;
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mp_limb_t * B_terms = qs_inf->B_terms;
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prime_t * factor_base = qs_inf->factor_base;
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mp_limb_t A = qs_inf->A;
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mp_limb_t B;
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mp_limb_t p, temp, temp2, pinv;
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slong i;
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for (i = 0; i < s; i++)
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{
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p = factor_base[A_ind[i]].p;
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pinv = factor_base[A_ind[i]].pinv;
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temp = A/p; /* TODO: possibly use precomputed inverse here */
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A_modp[i] = (temp2 = n_mod2_preinv(temp, p, pinv));
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temp2 = n_invmod(temp2, p);
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temp2 = n_mulmod2_preinv(temp2, qs_inf->sqrts[A_ind[i]], p, pinv);
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if (temp2 > p/2) temp2 = p - temp2;
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B_terms[i] = temp*temp2;
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}
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B = B_terms[0];
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for (i = 1; i < s; i++)
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{
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B += B_terms[i];
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}
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qs_inf->B = B;
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}
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void qsieve_ll_compute_off_adj(qs_t qs_inf)
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{
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slong num_primes = qs_inf->num_primes;
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mp_limb_t A = qs_inf->A;
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mp_limb_t B = qs_inf->B;
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mp_limb_t * A_inv = qs_inf->A_inv;
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mp_limb_t ** A_inv2B = qs_inf->A_inv2B;
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mp_limb_t * B_terms = qs_inf->B_terms;
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mp_limb_t * soln1 = qs_inf->soln1;
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mp_limb_t * soln2 = qs_inf->soln2;
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int * sqrts = qs_inf->sqrts;
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prime_t * factor_base = qs_inf->factor_base;
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slong s = qs_inf->s;
|
||
|
|
mp_limb_t p, temp, pinv;
|
||
|
|
slong i, j;
|
||
|
|
|
||
|
|
for (i = 2; i < num_primes; i++) /* skip k and 2 */
|
||
|
|
{
|
||
|
|
p = factor_base[i].p;
|
||
|
|
pinv = factor_base[i].pinv;
|
||
|
|
|
||
|
|
A_inv[i] = n_invmod(n_mod2_preinv(A, p, pinv), p);
|
||
|
|
|
||
|
|
for (j = 0; j < s; j++)
|
||
|
|
{
|
||
|
|
temp = n_mod2_preinv(B_terms[j], p, pinv);
|
||
|
|
temp = n_mulmod2_preinv(temp, A_inv[i], p, pinv);
|
||
|
|
temp *= 2;
|
||
|
|
if (temp >= p) temp -= p;
|
||
|
|
A_inv2B[j][i] = temp;
|
||
|
|
}
|
||
|
|
|
||
|
|
temp = n_mod2_preinv(B, p, pinv);
|
||
|
|
temp = sqrts[i] + p - temp;
|
||
|
|
temp *= A_inv[i];
|
||
|
|
temp += qs_inf->sieve_size/2;
|
||
|
|
soln1[i] = n_mod2_preinv(temp, p, pinv);
|
||
|
|
temp = p - sqrts[i];
|
||
|
|
if (temp == p) temp -= p;
|
||
|
|
temp = n_mulmod2_preinv(temp, A_inv[i], p, pinv);
|
||
|
|
temp *= 2;
|
||
|
|
if (temp >= p) temp -= p;
|
||
|
|
soln2[i] = temp + soln1[i];
|
||
|
|
if (soln2[i] >= p) soln2[i] -= p;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
void qsieve_ll_compute_A_factor_offsets(qs_t qs_inf)
|
||
|
|
{
|
||
|
|
slong s = qs_inf->s;
|
||
|
|
mp_limb_t * A_ind = qs_inf->A_ind;
|
||
|
|
mp_limb_t * A_modp = qs_inf->A_modp;
|
||
|
|
mp_limb_t * soln1 = qs_inf->soln1;
|
||
|
|
mp_limb_t * soln2 = qs_inf->soln2;
|
||
|
|
mp_limb_t p, D;
|
||
|
|
mp_limb_t hi = qs_inf->hi;
|
||
|
|
mp_limb_t lo = qs_inf->lo;
|
||
|
|
mp_limb_t B = qs_inf->B;
|
||
|
|
mp_limb_t temp, temp2, B_modp2, index, p2;
|
||
|
|
prime_t * factor_base = qs_inf->factor_base;
|
||
|
|
mp_limb_t * inv_p2 = qs_inf->inv_p2;
|
||
|
|
mp_limb_t pinv;
|
||
|
|
slong j;
|
||
|
|
|
||
|
|
for (j = 0; j < s; j++)
|
||
|
|
{
|
||
|
|
index = A_ind[j];
|
||
|
|
p = factor_base[index].p;
|
||
|
|
p2 = p*p;
|
||
|
|
pinv = factor_base[index].pinv;
|
||
|
|
D = n_ll_mod_preinv(hi, lo, p*p, inv_p2[j]);
|
||
|
|
if ((mp_limb_signed_t) B < 0)
|
||
|
|
{
|
||
|
|
B_modp2 = n_mod2_preinv(-B, p2, inv_p2[j]);
|
||
|
|
B_modp2 = p2 - B_modp2;
|
||
|
|
if (B_modp2 == p2) B_modp2 = 0;
|
||
|
|
} else
|
||
|
|
B_modp2 = n_mod2_preinv(B, p2, inv_p2[j]);
|
||
|
|
temp = B_modp2*A_modp[j];
|
||
|
|
temp = n_mod2_preinv(temp, p, pinv);
|
||
|
|
temp2 = n_invmod(temp, p);
|
||
|
|
D -= (B_modp2*B_modp2);
|
||
|
|
if ((mp_limb_signed_t) D < 0)
|
||
|
|
temp = -(-D/p); /* TODO consider using precomputed inverse */
|
||
|
|
else
|
||
|
|
temp = (D/p); /* TODO consider using precomputed inverse */
|
||
|
|
temp *= temp2;
|
||
|
|
temp += qs_inf->sieve_size/2;
|
||
|
|
if ((mp_limb_signed_t) temp < 0)
|
||
|
|
{
|
||
|
|
temp = p - n_mod2_preinv(-temp, p, pinv);
|
||
|
|
if (temp == p) temp = 0;
|
||
|
|
}
|
||
|
|
else temp = n_mod2_preinv(temp, p, pinv);
|
||
|
|
soln1[index] = temp;
|
||
|
|
soln2[index] = -1;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
void qsieve_ll_compute_C(qs_t qs_inf)
|
||
|
|
{
|
||
|
|
mp_limb_t A = qs_inf->A;
|
||
|
|
mp_limb_t B = qs_inf->B;
|
||
|
|
|
||
|
|
if ((mp_limb_signed_t) B < WORD(0)) B = -B;
|
||
|
|
fmpz_set_ui(qs_inf->C, B);
|
||
|
|
fmpz_mul_ui(qs_inf->C, qs_inf->C, B);
|
||
|
|
fmpz_sub(qs_inf->C, qs_inf->C, qs_inf->kn);
|
||
|
|
fmpz_divexact_ui(qs_inf->C, qs_inf->C, A);
|
||
|
|
}
|
||
|
|
|
||
|
|
void qsieve_ll_compute_poly_data(qs_t qs_inf)
|
||
|
|
{
|
||
|
|
qsieve_ll_compute_A(qs_inf);
|
||
|
|
qsieve_ll_compute_B_terms(qs_inf);
|
||
|
|
qsieve_ll_compute_off_adj(qs_inf);
|
||
|
|
qsieve_ll_compute_A_factor_offsets(qs_inf);
|
||
|
|
qsieve_ll_compute_C(qs_inf);
|
||
|
|
}
|
||
|
|
|