pqc/external/flint-2.4.3/nmod_mat/randrank.c
2014-05-24 23:16:06 +02:00

53 lines
1.6 KiB
C

/*=============================================================================
This file is part of FLINT.
FLINT 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.
FLINT 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 FLINT; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
=============================================================================*/
/******************************************************************************
Copyright (C) 2010 Fredrik Johansson
******************************************************************************/
#include <stdio.h>
#include "flint.h"
#include "ulong_extras.h"
#include "nmod_mat.h"
#include "nmod_vec.h"
void
nmod_mat_randrank(nmod_mat_t mat, flint_rand_t state, slong rank)
{
slong i;
mp_limb_t * diag;
if (rank < 0 || rank > mat->r || rank > mat->c)
{
flint_printf("Exception (nmod_mat_randrank). Impossible rank.\n");
abort();
}
diag = _nmod_vec_init(rank);
for (i = 0; i < rank; i++)
diag[i] = 1 + n_randint(state, mat->mod.n - 1);
nmod_mat_randpermdiag(mat, state, diag, rank);
_nmod_vec_clear(diag);
}