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/*=============================================================================
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 William Hart
Copyright (C) 2013 Mike Hansen
******************************************************************************/
#include <gmp.h>
#include <stdlib.h>
#include "flint.h"
#include "ulong_extras.h"
#include "nmod_poly.h"
void
nmod_poly_randtest(nmod_poly_t poly, flint_rand_t state, slong len)
{
nmod_poly_fit_length(poly, len);
_nmod_vec_randtest(poly->coeffs, state, len, poly->mod);
poly->length = len;
_nmod_poly_normalise(poly);
}
void
nmod_poly_randtest_monic(nmod_poly_t poly, flint_rand_t state, slong len)
{
nmod_poly_fit_length(poly, len);
_nmod_vec_randtest(poly->coeffs, state, len - 1, poly->mod);
poly->coeffs[len - 1] = 1;
poly->length = len;
}
void
nmod_poly_randtest_irreducible(nmod_poly_t poly, flint_rand_t state, slong len)
{
do {
nmod_poly_randtest(poly, state, len);
} while (nmod_poly_is_zero(poly) || !(nmod_poly_is_irreducible(poly)));
}
void
nmod_poly_randtest_monic_irreducible(nmod_poly_t poly, flint_rand_t state, slong len)
{
do {
nmod_poly_randtest_monic(poly, state, len);
} while (nmod_poly_is_zero(poly) || !(nmod_poly_is_irreducible(poly)));
}
void
nmod_poly_randtest_trinomial(nmod_poly_t poly, flint_rand_t state, slong len)
{
ulong k;
nmod_poly_fit_length(poly, len);
_nmod_vec_zero(poly->coeffs, len);
poly->coeffs[0] = n_randtest(state) % poly->mod.n;
poly->coeffs[len - 1] = 1;
k = (n_randtest(state) % (len - 2)) + 1;
poly->coeffs[k] = n_randtest(state) % poly->mod.n;
_nmod_poly_set_length(poly, len);
}
void
nmod_poly_randtest_pentomial(nmod_poly_t poly, flint_rand_t state, slong len)
{
nmod_poly_fit_length(poly, len);
_nmod_vec_zero(poly->coeffs, len);
poly->coeffs[0] = n_randtest(state) % poly->mod.n;
poly->coeffs[1] = n_randtest(state) % poly->mod.n;
poly->coeffs[2] = n_randtest(state) % poly->mod.n;
poly->coeffs[3] = n_randtest(state) % poly->mod.n;
poly->coeffs[len - 1] = 1;
_nmod_poly_set_length(poly, len);
}
int
nmod_poly_randtest_trinomial_irreducible(nmod_poly_t poly, flint_rand_t state,
slong len, slong max_attempts)
{
slong i = 0;
while (max_attempts == 0 || i < max_attempts)
{
nmod_poly_randtest_trinomial(poly, state, len);
if (!nmod_poly_is_zero(poly) && nmod_poly_is_irreducible(poly))
{
return 1;
}
i++;
}
return 0;
}
int
nmod_poly_randtest_pentomial_irreducible(nmod_poly_t poly, flint_rand_t state,
slong len, slong max_attempts)
{
slong i = 0;
while (max_attempts == 0 || i < max_attempts)
{
nmod_poly_randtest_pentomial(poly, state, len);
if (!nmod_poly_is_zero(poly) && nmod_poly_is_irreducible(poly))
{
return 1;
}
i++;
}
return 0;
}
void
nmod_poly_randtest_sparse_irreducible(nmod_poly_t poly, flint_rand_t state, slong len)
{
if (len < 3)
{
nmod_poly_randtest_monic_irreducible(poly, state, len);
return;
}
/* Try trinomials */
if (nmod_poly_randtest_trinomial_irreducible(poly, state, len, 2*len))
return;
if (len < 5)
{
nmod_poly_randtest_monic_irreducible(poly, state, len);
return;
}
/* Try pentomials */
if (nmod_poly_randtest_pentomial_irreducible(poly, state, len, 2*len))
return;
/* Give up */
nmod_poly_randtest_monic_irreducible(poly, state, len);
}
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