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https://github.com/vale981/arb
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48 lines
1.7 KiB
C
48 lines
1.7 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) 2016 Pascal Molin
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******************************************************************************/
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#include <stdlib.h>
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#include "dlog.h"
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ulong
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dlog_bsgs(const dlog_bsgs_t t, ulong b)
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{
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ulong i;
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apow_t c, * x;
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c.ak = b;
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for (i = 0; i < t->g; i++)
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{
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x = bsearch(&c, t->table, t->m, sizeof(apow_t),
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(int(*)(const void*,const void*))apow_cmp);
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if (x != NULL)
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return i * t->m + x->k;
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c.ak = nmod_mul(c.ak, t->am, t->mod);
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}
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flint_printf("Exception (dlog_bsgs). discrete log not found.\n");
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flint_printf(" table size %wu, cosize %wu mod %wu. %wu not found (a^-m=%wu)\n",
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t->m, t->g, t->mod.n, b, t->am);
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abort();
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}
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