mirror of
https://github.com/vale981/arb
synced 2025-03-04 17:01:40 -05:00
44 lines
1.1 KiB
C
44 lines
1.1 KiB
C
/*
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Copyright (C) 2016 Pascal Molin
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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 it under
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the terms of the GNU Lesser General Public License (LGPL) as published
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by the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version. See <http://www.gnu.org/licenses/>.
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*/
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#include "dlog.h"
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/* todo: recursion could be made quadratic (not very useful for ulongs) */
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ulong
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dlog_modpe_init(dlog_modpe_t t, ulong a, ulong p, ulong e, ulong pe, ulong num)
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{
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ulong a1;
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t->p = p;
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t->e = e;
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nmod_init(&t->pe, pe);
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t->inva = nmod_inv(a, t->pe);
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if (p == 2)
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{
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t->modp = NULL;
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t->pe1 = (e <= 2) ? 2 : pe / 4;
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t->modpe->inv1p = t->inva;
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t->modpe->invloga1 = 1;
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return e - 2;
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}
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else
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{
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t->modp = flint_malloc(sizeof(dlog_precomp_struct));
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t->pe1 = pe / p;
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dlog_precomp_n_init(t->modp, a, p, p - 1, num);
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a1 = nmod_pow_ui(a, p - 1, t->pe);
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dlog_1modpe_init(t->modpe, a1, p, e, t->pe);
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return t->modp->cost + e;
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}
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}
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