arb/dlog/vec_loop_add.c
2016-09-06 16:23:12 +02:00

27 lines
805 B
C

/*
Copyright (C) 2016 Pascal Molin
This file is part of Arb.
Arb 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 2.1 of the License, or
(at your option) any later version. See <http://www.gnu.org/licenses/>.
*/
#include "dlog.h"
/* vector of log(k,a)*loga % order in Z/modZ */
void
dlog_vec_loop_add(ulong * v, ulong nv, ulong a, ulong va, nmod_t mod, ulong na, nmod_t order)
{
ulong x, xp, vx;
vx = 0;
for (x = a; x != 1; x = nmod_mul(x, a, mod))
{
vx = nmod_add(vx, va, order);
for(xp = x; xp < nv; xp+=mod.n)
if (v[xp] != DLOG_NONE)
v[xp] = nmod_add(v[xp], vx, order);
}
}