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/*
Copyright (C) 2016 Pascal Molin
This file is part of FLINT.
FLINT is free software: you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License (LGPL) as published
by the Free Software Foundation; either version 3 of the License, or
(at your option) any later version. See <https://www.gnu.org/licenses/>.
*/
#include "nmod.h"
#include "dlog.h"
/* assume non invertible and 1 mod n already set */
void
dlog_vec_eratos_add(ulong *v, ulong nv, ulong a, ulong va, nmod_t mod, ulong na, nmod_t order)
{
ulong p, k, n;
dlog_precomp_t pre;
n_primes_t iter;
/* discrete log on primes */
n = (nv < mod.n) ? nv : mod.n;
dlog_precomp_n_init(pre, a, mod.n, na, n_prime_pi(n));
n_primes_init(iter);
while ((p = n_primes_next(iter)) < n)
{
ulong wp, pe;
if (v[p] == DLOG_NOT_FOUND)
continue; /* won't be attained another time */
wp = nmod_mul(dlog_precomp(pre, p), va, order);
/* FIXME: could be faster sieving m*pe? but cannot
* use v[p*m]=v[p]*v[m]... */
for (pe = p; pe < n; pe *= p)
for (k = pe; k < n; k += pe)
if (v[k] != DLOG_NOT_FOUND)
v[k] = nmod_add(v[k], wp, order);
}
n_primes_clear(iter);
for (k = mod.n + 1; k < nv; k++)
v[k] = v[k - mod.n];
dlog_precomp_clear(pre);
}