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

139 lines
3.6 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) 2012 Fredrik Johansson
******************************************************************************/
#include "flint.h"
#include "nmod_poly.h"
#include "nmod_poly_mat.h"
void
nmod_poly_mat_sqr_interpolate(nmod_poly_mat_t C, const nmod_poly_mat_t A)
{
slong i, j, k;
slong A_len, len;
nmod_mat_t *C_mod, *A_mod;
mp_ptr xs;
mp_ptr tt, uu;
mp_ptr * tree;
mp_ptr weights;
nmod_t mod;
if (A->c == 0)
{
nmod_poly_mat_zero(C);
return;
}
A_len = nmod_poly_mat_max_length(A);
if (A_len == 0)
{
nmod_poly_mat_zero(C);
return;
}
len = 2 * A_len - 1;
nmod_init(&mod, nmod_poly_mat_modulus(A));
if (mod.n < len)
{
flint_printf("Exception (nmod_poly_mat_sqr_interpolate). \n"
"Characteristic is too small.\n");
abort();
}
xs = _nmod_vec_init(len);
tt = _nmod_vec_init(len);
uu = _nmod_vec_init(len);
weights = _nmod_vec_init(len);
A_mod = flint_malloc(sizeof(nmod_mat_t) * len);
C_mod = flint_malloc(sizeof(nmod_mat_t) * len);
for (i = 0; i < len; i++)
{
xs[i] = i;
nmod_mat_init(A_mod[i], A->r, A->c, mod.n);
nmod_mat_init(C_mod[i], C->r, C->c, mod.n);
}
tree = _nmod_poly_tree_alloc(len);
_nmod_poly_tree_build(tree, xs, len, mod);
_nmod_poly_interpolation_weights(weights, tree, len, mod);
for (i = 0; i < A->r; i++)
{
for (j = 0; j < A->c; j++)
{
_nmod_poly_evaluate_nmod_vec_fast_precomp(tt,
nmod_poly_mat_entry(A, i, j)->coeffs,
nmod_poly_mat_entry(A, i, j)->length,
tree, len, mod);
for (k = 0; k < len; k++)
A_mod[k]->rows[i][j] = tt[k];
}
}
/* should be nmod_mat_sqr */
for (i = 0; i < len; i++)
nmod_mat_mul(C_mod[i], A_mod[i], A_mod[i]);
for (i = 0; i < C->r; i++)
{
for (j = 0; j < C->c; j++)
{
nmod_poly_struct * poly;
for (k = 0; k < len; k++)
tt[k] = C_mod[k]->rows[i][j];
poly = nmod_poly_mat_entry(C, i, j);
nmod_poly_fit_length(poly, len);
_nmod_poly_interpolate_nmod_vec_fast_precomp(poly->coeffs,
tt, tree, weights, len, mod);
poly->length = len;
_nmod_poly_normalise(poly);
}
}
_nmod_poly_tree_free(tree, len);
for (i = 0; i < len; i++)
{
nmod_mat_clear(A_mod[i]);
nmod_mat_clear(C_mod[i]);
}
flint_free(A_mod);
flint_free(C_mod);
_nmod_vec_clear(xs);
_nmod_vec_clear(tt);
_nmod_vec_clear(uu);
_nmod_vec_clear(weights);
}