pqc/external/flint-2.4.3/qsieve/ll_collect_relations.c

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2014-05-18 22:03:37 +00:00
/*=============================================================================
This file is part of FLINT.
FLINT 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.
FLINT 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 FLINT; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
=============================================================================*/
/******************************************************************************
Copyright (C) 2006, 2011 William Hart
******************************************************************************/
#define ulong ulongxx /* interferes with system includes */
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#undef ulong
#define ulong mp_limb_t
#include <gmp.h>
#include "flint.h"
#include "ulong_extras.h"
#include "qsieve.h"
#include "fmpz.h"
void qsieve_ll_do_sieving(qs_t qs_inf, char * sieve)
{
slong num_primes = qs_inf->num_primes;
mp_limb_t * soln1 = qs_inf->soln1;
mp_limb_t * soln2 = qs_inf->soln2;
prime_t * factor_base = qs_inf->factor_base;
mp_limb_t p;
char * end = sieve + qs_inf->sieve_size;
register char * pos1;
register char * pos2;
register char * bound;
slong size;
slong diff;
slong pind;
memset(sieve, 0, qs_inf->sieve_size + sizeof(ulong));
*end = (char) 255;
for (pind = qs_inf->small_primes; pind < num_primes; pind++)
{
if (soln2[pind] == -1) continue; /* don't sieve with A factors */
p = factor_base[pind].p;
size = factor_base[pind].size;
pos1 = sieve + soln1[pind];
pos2 = sieve + soln2[pind];
diff = pos2 - pos1;
bound = end - 2*p;
while (bound - pos1 > 0)
{
(*pos1) += size, (*(pos1 + diff)) += size, pos1 += p;
(*pos1) += size, (*(pos1 + diff)) += size, pos1 += p;
}
while ((end - pos1 > 0) && (end - pos1 - diff > 0))
{
(*pos1) += size, (*(pos1 + diff)) += size, pos1 += p;
}
pos2 = pos1 + diff;
if (end - pos2 > 0)
{
(*pos2) += size;
}
if (end - pos1 > 0)
{
(*pos1) += size;
}
}
}
slong qsieve_ll_evaluate_candidate(qs_t qs_inf, slong i, char * sieve)
{
slong bits, exp, extra_bits;
mp_limb_t modp, prime;
slong num_primes = qs_inf->num_primes;
prime_t * factor_base = qs_inf->factor_base;
fac_t * factor = qs_inf->factor;
mp_limb_t * soln1 = qs_inf->soln1;
mp_limb_t * soln2 = qs_inf->soln2;
slong * small = qs_inf->small;
mp_limb_t A = qs_inf->A;
mp_limb_t B = qs_inf->B;
mp_limb_t pinv;
slong num_factors = 0;
slong relations = 0;
slong j;
fmpz_t X, Y, res, p;
fmpz_init(X);
fmpz_init(Y);
fmpz_init(res);
fmpz_init(p);
fmpz_set_ui(X, i);
fmpz_sub_ui(X, X, qs_inf->sieve_size/2); /* X */
#if (QS_DEBUG & 32)
flint_printf("i = "); fmpz_print(X); flint_printf("\n");
#endif
fmpz_mul_ui(Y, X, A);
if ((mp_limb_signed_t) B < 0)
{
fmpz_sub_ui(Y, Y, -B); /* Y = AX + B */
fmpz_sub_ui(res, Y, -B);
} else
{
fmpz_add_ui(Y, Y, B);
fmpz_add_ui(res, Y, B);
}
fmpz_mul(res, res, X);
fmpz_add(res, res, qs_inf->C); /* res = AX^2 + 2BX + C */
bits = FLINT_ABS(fmpz_bits(res));
bits -= BITS_ADJUST;
extra_bits = 0;
fmpz_set_ui(p, 2); /* divide out by powers of 2 */
exp = fmpz_remove(res, res, p);
#if (QS_DEBUG & 8)
if (exp) flint_printf("2^%wd ", exp);
#endif
extra_bits += exp;
small[1] = exp;
if (factor_base[0].p != 1) /* divide out powers of the multiplier */
{
fmpz_set_ui(p, factor_base[0].p);
exp = fmpz_remove(res, res, p);
if (exp) extra_bits += exp*qs_inf->factor_base[0].size;
small[0] = exp;
#if (QS_DEBUG & 8)
if (exp) flint_printf("%d^%wd ", factor_base[0].p, exp);
#endif
} else small[0] = 0;
for (j = 2; j < qs_inf->small_primes; j++) /* pull out small primes */
{
prime = factor_base[j].p;
pinv = factor_base[j].pinv;
modp = n_mod2_preinv(i, prime, pinv);
if ((modp == soln1[j]) || (modp == soln2[j]))
{
fmpz_set_ui(p, prime);
exp = fmpz_remove(res, res, p);
if (exp) extra_bits += qs_inf->factor_base[j].size;
small[j] = exp;
#if (QS_DEBUG & 8)
if (exp)
{
fmpz_print(p);
flint_printf("^%wd ", exp);
}
#endif
} else small[j] = 0;
}
if (extra_bits + sieve[i] > bits)
{
sieve[i] += extra_bits;
/* pull out remaining primes */
for (j = qs_inf->small_primes; j < num_primes && extra_bits < sieve[i]; j++)
{
prime = factor_base[j].p;
pinv = factor_base[j].pinv;
modp = n_mod2_preinv(i, prime, pinv);
if (soln2[j] != -1)
{
if ((modp == soln1[j]) || (modp == soln2[j]))
{
fmpz_set_ui(p, prime);
exp = fmpz_remove(res, res, p);
#if (QS_DEBUG & 8)
if (exp)
{
fmpz_print(p);
flint_printf("^%wd ", exp);
}
#endif
if (exp)
{
extra_bits += qs_inf->factor_base[j].size;
factor[num_factors].ind = j;
factor[num_factors++].exp = exp;
}
}
} else
{
fmpz_set_ui(p, prime);
exp = fmpz_remove(res, res, p);
factor[num_factors].ind = j;
factor[num_factors++].exp = exp + 1;
#if (QS_DEBUG & 8)
if (exp)
{
fmpz_print(p);
flint_printf("^%wd ", exp);
}
#endif
}
}
if (fmpz_cmp_ui(res, 1) == 0 || fmpz_cmp_si(res, -1) == 0) /* We've found a relation */
{
mp_limb_t * A_ind = qs_inf->A_ind;
slong i;
for (i = 0; i < qs_inf->s; i++) /* Commit any outstanding A factors */
{
if (A_ind[i] >= j)
{
factor[num_factors].ind = A_ind[i];
factor[num_factors++].exp = 1;
}
}
qs_inf->num_factors = num_factors;
relations += qsieve_ll_insert_relation(qs_inf, Y); /* Insert the relation in the matrix */
if (qs_inf->num_relations >= qs_inf->buffer_size)
{
flint_printf("Error: too many duplicate relations!\n");
flint_printf("s = %wd, bits = %wd\n", qs_inf->s, qs_inf->bits);
abort();
}
goto cleanup;
}
}
#if (QS_DEBUG & 8)
flint_printf("\n");
#endif
cleanup:
fmpz_clear(X);
fmpz_clear(Y);
fmpz_clear(res);
fmpz_clear(p);
return relations;
}
slong qsieve_ll_evaluate_sieve(qs_t qs_inf, char * sieve)
{
slong i = 0, j = 0;
ulong * sieve2 = (ulong *) sieve;
char bits = qs_inf->sieve_bits;
slong rels = 0;
#if (QS_DEBUG & 16)
slong stats_limit;
for (i = 0; i < 256; i++)
qs_inf->sieve_tally[i] = 0;
#endif
#if (QS_DEBUG & 4)
flint_printf("%wdX^2+2*%wdX+", qs_inf->A, qs_inf->B);
fmpz_print(qs_inf->C); flint_printf("\n");
#endif
while (j < qs_inf->sieve_size/sizeof(ulong))
{
#if FLINT64
while ((sieve2[j] & UWORD(0xE0E0E0E0E0E0E0E0)) == 0)
#else
while ((sieve2[j] & UWORD(0xE0E0E0E0)) == 0)
#endif
{
#if (QS_DEBUG & 16)
for (i = j*sizeof(ulong); i < (j+1)*sizeof(ulong) && i < qs_inf->sieve_size; i++)
qs_inf->sieve_tally[(int)sieve[i]]++;
#endif
j++;
}
i = j*sizeof(ulong);
while (i < (j+1)*sizeof(ulong) && i < qs_inf->sieve_size)
{
#if (QS_DEBUG & 16)
qs_inf->sieve_tally[(int)sieve[i]]++;
#endif
if (sieve[i] > bits)
rels += qsieve_ll_evaluate_candidate(qs_inf, i, sieve);
i++;
}
j++;
}
#if (QS_DEBUG & 16)
for (stats_limit = 255; stats_limit >= 0; stats_limit--)
if (qs_inf->sieve_tally[stats_limit] != 0)
break;
for (i = 0; i <= stats_limit; i++)
{
if ((i % 16) == 0)
flint_printf("|%wd:", i);
flint_printf(" %wd", qs_inf->sieve_tally[i]);
}
flint_printf("|\n");
flint_printf("Total of %wd relations for this sieve interval\n", rels);
#endif
return rels;
}
void qsieve_ll_update_offsets(int poly_add, mp_limb_t * poly_corr, qs_t qs_inf)
{
slong num_primes = qs_inf->num_primes;
mp_limb_t * soln1 = qs_inf->soln1;
mp_limb_t * soln2 = qs_inf->soln2;
prime_t * factor_base = qs_inf->factor_base;
mp_limb_t p, correction;
slong pind;
for (pind = 2; pind < num_primes; pind++)
{
p = factor_base[pind].p;
correction = (poly_add ? p - poly_corr[pind] : poly_corr[pind]);
soln1[pind] += correction;
if (soln1[pind] >= p) soln1[pind] -= p;
if (soln2[pind] == -1) continue;
soln2[pind] += correction;
if (soln2[pind] >= p) soln2[pind] -= p;
}
}
slong qsieve_ll_collect_relations(qs_t qs_inf, char * sieve)
{
slong s = qs_inf->s;
mp_limb_t ** A_inv2B = qs_inf->A_inv2B;
mp_limb_t * poly_corr;
slong relations = 0;
slong poly_index, j;
int poly_add;
qsieve_ll_compute_poly_data(qs_inf);
for (poly_index = 1; poly_index < (1<<(s - 1)); poly_index++)
{
for (j = 0; j < s; j++)
if (((poly_index >> j) & UWORD(1)) != UWORD(0)) break;
poly_add = ((poly_index >> j) & 2);
poly_corr = A_inv2B[j];
qsieve_ll_do_sieving(qs_inf, sieve);
relations += qsieve_ll_evaluate_sieve(qs_inf, sieve);
qsieve_ll_update_offsets(poly_add, poly_corr, qs_inf);
if (poly_add) qs_inf->B += (2*qs_inf->B_terms[j]);
else qs_inf->B -= (2*qs_inf->B_terms[j]);
qsieve_ll_compute_C(qs_inf);
qsieve_ll_compute_A_factor_offsets(qs_inf);
if (qs_inf->columns >= qs_inf->num_primes + qs_inf->extra_rels)
break;
}
if (qs_inf->columns < qs_inf->num_primes + qs_inf->extra_rels)
{
qsieve_ll_do_sieving(qs_inf, sieve);
relations += qsieve_ll_evaluate_sieve(qs_inf, sieve);
relations += qsieve_ll_merge_relations(qs_inf);
}
return relations;
}