arb/acb_dirichlet/test/t-thetanull.c
2016-09-06 14:33:53 +02:00

143 lines
4.3 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"
int main()
{
slong prec = 64;
ulong q;
flint_printf("thetanull....");
fflush(stdout);
/* check the only theta functions
* theta(chi) = sum chi(k)* k^odd * exp(-Pi * k^2 / q)
* vanishing at 1 correspond to two specific
* characters of moduli 300 and 600 + conjugates
*/
for (q = 3; q < 1000; q ++)
{
acb_dirichlet_group_t G;
acb_dirichlet_conrey_t x;
acb_dirichlet_char_t chi;
ulong * v, nv, k;
acb_t zeta, sum;
acb_ptr z;
arb_t eq;
arb_ptr t, kt, tt;
if (q % 4 == 2)
/* no primitive character mod q */
continue;
acb_dirichlet_group_init(G, q);
acb_dirichlet_conrey_init(x, G);
acb_dirichlet_char_init(chi, G);
acb_init(zeta);
acb_dirichlet_nth_root(zeta, G->expo, prec);
z = _acb_vec_init(G->expo);
_acb_vec_set_powers(z, zeta, G->expo, prec);
nv = acb_dirichlet_theta_length_d(q, 1, prec);
v = flint_malloc(nv * sizeof(ulong));
arb_init(eq);
arb_const_pi(eq, prec);
arb_div_ui(eq, eq, q, prec);
arb_neg(eq, eq);
arb_exp(eq, eq, prec);
t = _arb_vec_init(nv);
acb_dirichlet_arb_quadratic_powers(t, nv, eq, prec);
kt = _arb_vec_init(nv);
for (k = 1; k < nv; k++)
arb_mul_ui(kt + k, t + k, k, prec);
/* theta function on primitive characters */
acb_init(sum);
acb_dirichlet_conrey_first_primitive(x, G);
while (1) {
ulong m;
acb_zero(sum);
acb_dirichlet_char_conrey(chi, G, x);
acb_dirichlet_ui_chi_vec(v, G, chi, nv);
m = G->expo / chi->order;
tt = acb_dirichlet_char_parity(chi) ? kt : t;
for (k = 1; k < nv; k++)
if (v[k] != ACB_DIRICHLET_CHI_NULL)
acb_addmul_arb(sum, z + (v[k] * m), tt + k, prec);
if ((q == 300 && (chi->x->n == 271 || chi->x->n == 131))
|| (q == 600 && (chi->x->n == 11 || chi->x->n == 91)))
{
if (!acb_contains_zero(sum))
{
flint_printf("FAIL: Theta(chi_%wu(%wu))=", q, chi->x->n);
acb_printd(sum, 10);
flint_printf("\n");
acb_dirichlet_char_print(G, chi);
flint_printf("\n");
abort();
}
}
else if (acb_contains_zero(sum))
{
flint_printf("FAIL: Theta(chi_%wu(%wu))=", q, chi->x->n);
acb_printd(sum, 10);
flint_printf("\n");
acb_dirichlet_char_print(G, chi);
flint_printf("\n");
abort();
}
if (acb_dirichlet_conrey_next_primitive(x, G) == G->num)
break;
}
_acb_vec_clear(z, G->expo);
_arb_vec_clear(t, nv);
acb_clear(zeta);
acb_clear(sum);
arb_clear(eq);
flint_free(v);
acb_dirichlet_group_clear(G);
acb_dirichlet_char_clear(chi);
acb_dirichlet_conrey_clear(x);
}
flint_cleanup();
flint_printf("PASS\n");
return EXIT_SUCCESS;
}