arb/acb_dirichlet/group_init.c
2016-02-21 23:23:51 +01:00

98 lines
2.6 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) 2015 Jonathan Bober
Copyright (C) 2016 Fredrik Johansson
******************************************************************************/
#include "acb_dirichlet.h"
static ulong
primitive_root_p_and_p2(ulong p)
{
if (p == 40487)
return 10;
#if FLINT_BITS == 64
if (p == UWORD(6692367337))
return 7;
if (p > UWORD(1000000000000))
{
printf("primitive root: p > 10^12 not implemented");
abort();
}
#endif
return n_primitive_root_prime(p);
}
void
acb_dirichlet_group_init(acb_dirichlet_group_t G, ulong q)
{
slong k;
n_factor_t fac;
G->q = q;
G->q_odd = q;
G->q_even = 1;
while (G->q_odd % 2 == 0)
{
G->q_odd /= 2;
G->q_even *= 2;
}
n_factor_init(&fac);
n_factor(&fac, G->q_odd, 1);
G->num = fac.num;
G->primes = flint_malloc(G->num * sizeof(ulong));
G->exponents = flint_malloc(G->num * sizeof(ulong));
G->generators = flint_malloc(G->num * sizeof(ulong));
G->PHI = flint_malloc(G->num * sizeof(ulong));
for (k = 0; k < G->num; k++)
{
G->primes[k] = fac.p[k];
G->exponents[k] = fac.exp[k];
}
G->phi_q_odd = 1;
for (k = 0; k < G->num; k++)
G->phi_q_odd *= (G->primes[k] - 1) * n_pow(G->primes[k], G->exponents[k]-1);
if (G->q_even == 1)
G->phi_q = G->phi_q_odd;
else
G->phi_q = G->phi_q_odd * (G->q_even / 2);
for (k = 0; k < G->num; k++)
{
ulong phi;
G->generators[k] = primitive_root_p_and_p2(G->primes[k]);
phi = n_pow(G->primes[k], G->exponents[k] - 1) * (G->primes[k] - 1);
G->PHI[k] = G->phi_q_odd / phi;
}
}