mirror of
https://github.com/vale981/arb
synced 2025-03-06 01:41:39 -05:00
146 lines
3.8 KiB
C
146 lines
3.8 KiB
C
/*=============================================================================
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This file is part of ARB.
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ARB 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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ARB 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 ARB; 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) 2016 Pascal Molin
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******************************************************************************/
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#include "math.h"
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#include "dlog.h"
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#define TABLE_P_LIM 50
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#define TABLE_PE_LIM 50
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#define TABLE_N_LIM 50
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#define BSGS_LIM 500
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/* log mod p^e */
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void
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dlog_precomp_modpe_init(dlog_precomp_t pre, ulong a, ulong p, ulong e, ulong pe, ulong num)
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{
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if ( pe < TABLE_PE_LIM )
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{
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pre->type = DLOG_TABLE;
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dlog_table_init(pre->t.table, a, pe);
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return;
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}
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if (e > 1)
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{
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pre->type = DLOG_MODPE;
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dlog_modpe_init(pre->t.modpe, a, p, e, pe, num);
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}
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else
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{
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dlog_precomp_n_init(pre, a, p, p - 1, num);
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}
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}
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/* group of order n modulo mod, mod a prime and no information on n */
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void
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dlog_precomp_n_init(dlog_precomp_t pre, ulong a, ulong mod, ulong n, ulong num)
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{
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if (n%2 && n_is_probabprime(n))
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dlog_precomp_p_init(pre, a, mod, n, num);
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else {
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if ( mod < TABLE_N_LIM )
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{
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pre->type = DLOG_TABLE;
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dlog_table_init(pre->t.table, a, mod);
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} else {
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if (n < BSGS_LIM)
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{
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ulong m;
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m = (2 * num < n) ? ceil(sqrt((double) n * num)) : n;
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pre->type = DLOG_BSGS;
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dlog_bsgs_init(pre->t.bsgs, a, mod, n, m);
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} else {
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pre->type = DLOG_CRT;
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dlog_crt_init(pre->t.crt, a, mod, n, num);
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}
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}
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}
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}
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/* we known the order is prime */
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void
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dlog_precomp_p_init(dlog_precomp_t pre, ulong a, ulong mod, ulong p, ulong num)
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{
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if ( p < TABLE_P_LIM )
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{
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pre->type = DLOG_TABLE;
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dlog_table_init(pre->t.table, a, mod);
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}
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else
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{
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ulong m;
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m = (2 * num < p) ? ceil(sqrt((double) p * num)) : p;
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pre->type = DLOG_BSGS;
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dlog_bsgs_init(pre->t.bsgs, a, mod, p, m);
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}
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}
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void
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dlog_precomp_pe_init(dlog_precomp_t pre, ulong a, ulong mod, ulong p, ulong e, ulong pe, ulong num)
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{
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if ( pe < TABLE_PE_LIM )
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{
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pre->type = DLOG_TABLE;
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dlog_table_init(pre->t.table, a, mod);
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}
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else
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{
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if ( e == 1)
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{
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dlog_precomp_p_init(pre, a, mod, p, num);
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}
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else
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{
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pre->type = DLOG_POWER;
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dlog_power_init(pre->t.power, a, mod, p, e, num);
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}
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}
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}
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void
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dlog_precomp_clear(dlog_precomp_t pre)
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{
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switch (pre->type)
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{
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case DLOG_MODPE:
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dlog_modpe_clear(pre->t.modpe);
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break;
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case DLOG_CRT:
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dlog_crt_clear(pre->t.crt);
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break;
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case DLOG_POWER:
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dlog_power_clear(pre->t.power);
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break;
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case DLOG_TABLE:
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dlog_table_clear(pre->t.table);
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break;
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case DLOG_BSGS:
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dlog_bsgs_clear(pre->t.bsgs);
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break;
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default:
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abort();
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break;
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}
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}
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