arb/acb_dirichlet/jacobi_sum_naive.c

76 lines
2.3 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"
void
acb_dirichlet_jacobi_sum_naive(acb_t res, const acb_dirichlet_group_t G, const acb_dirichlet_char_t chi1, const acb_dirichlet_char_t chi2, slong prec)
{
ulong k1, k2, m1, m2, g, e;
ulong * v1, * v2;
slong *v;
nmod_t order;
acb_t z;
v1 = flint_malloc(G->q * sizeof(ulong));
v2 = flint_malloc(G->q * sizeof(ulong));
acb_dirichlet_ui_vec_set_null(v1, G, G->q);
acb_dirichlet_ui_chi_vec_loop(v1, G, chi1, G->q);
acb_dirichlet_ui_vec_set_null(v2, G, G->q);
acb_dirichlet_ui_chi_vec_loop(v2, G, chi2, G->q);
m1 = chi1->order;
m2 = chi2->order;
g = n_gcd(m1, m2);
nmod_init(&order, m1 * (m2 / g));
m1 = order.n / m1;
m2 = order.n / m2;
v = flint_malloc(order.n * sizeof(slong));
for (e = 0; e < order.n; e++)
v[e] = 0;
for (k1 = 2, k2 = G->q - 1; k2 > 1; k1++, k2--)
{
if (v1[k1] == ACB_DIRICHLET_CHI_NULL ||
v2[k2] == ACB_DIRICHLET_CHI_NULL)
continue;
e = nmod_add(v1[k1] * m1, v2[k2] * m2, order);
v[e]++;
}
acb_init(z);
acb_dirichlet_nth_root(z, order.n, prec);
acb_dirichlet_si_poly_evaluate(res, v, order.n, z, prec);
acb_clear(z);
flint_free(v);
flint_free(v2);
flint_free(v1);
}