pqc/external/flint-2.4.3/fmpq_mat/get_fmpz_mat_colwise.c

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2014-05-18 22:03:37 +00:00
/*=============================================================================
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) 2011 Fredrik Johansson
******************************************************************************/
#include "fmpq_mat.h"
void
fmpq_mat_get_fmpz_mat_colwise(fmpz_mat_t num, fmpz * den, const fmpq_mat_t mat)
{
fmpz_t t, lcm;
slong i, j;
if (fmpq_mat_is_empty(mat))
return;
fmpz_init(t);
fmpz_init(lcm);
for (j = 0; j < mat->c; j++)
{
/* Compute common denominator of column */
fmpz_set(lcm, fmpq_mat_entry_den(mat, 0, j));
for (i = 1; i < mat->r; i++)
fmpz_lcm(lcm, lcm, fmpq_mat_entry_den(mat, i, j));
if (den != NULL)
fmpz_set(den + j, lcm);
/* Rescale numerators in column */
if (fmpz_is_one(lcm))
{
for (i = 0; i < mat->r; i++)
fmpz_set(fmpz_mat_entry(num, i, j),
fmpq_mat_entry_num(mat, i, j));
}
else
{
for (i = 0; i < mat->r; i++)
{
fmpz_divexact(t, lcm, fmpq_mat_entry_den(mat, i, j));
fmpz_mul(fmpz_mat_entry(num, i, j),
fmpq_mat_entry_num(mat, i, j), t);
}
}
}
fmpz_clear(t);
fmpz_clear(lcm);
}