arb/acb_modular/psl2z_is_correct.c
2014-10-01 15:25:50 +02:00

47 lines
1.4 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) 2014 Fredrik Johansson
******************************************************************************/
#include "acb_modular.h"
int
psl2z_is_correct(const psl2z_t g)
{
int res;
fmpz_t t;
if (fmpz_sgn(&g->c) < 0)
return 0;
if (fmpz_is_zero(&g->c) && fmpz_sgn(&g->d) <= 0)
return 0;
fmpz_init(t);
fmpz_mul(t, &g->a, &g->d);
fmpz_submul(t, &g->b, &g->c);
res = fmpz_is_one(t);
fmpz_clear(t);
return res;
}