arb/acb_dirichlet/char_conductor.c

56 lines
1.8 KiB
C

/*=============================================================================
This file is part of ARB.
ARB is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
ARB is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with ARB; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
=============================================================================*/
/******************************************************************************
Copyright (C) 2016 Pascal Molin
******************************************************************************/
#include "acb_dirichlet.h"
ulong
acb_dirichlet_char_conductor(const acb_dirichlet_group_t G, const acb_dirichlet_char_t chi)
{
int k, f;
ulong cond = 1;
if (G->neven >= 1 && chi->expo[0] == 1)
cond = 4;
if (G->neven == 2 && chi->expo[1])
{
ulong l2 = chi->expo[1];
f = n_remove(&l2, 2);
cond = G->primepowers[1] >> f;
}
for (k = G->neven; k < G->neven; k++)
{
if (chi->expo[k])
{
ulong p, lp;
p = G->primes[k];
lp = chi->expo[k];
f = n_remove(&lp, p);
if (f)
cond *= n_pow(p, G->exponents[k] - f);
else
cond *= G->primepowers[k];
}
}
return cond;
}