237 lines
6.3 KiB
C
237 lines
6.3 KiB
C
/*=============================================================================
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This file is part of FLINT.
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FLINT is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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FLINT is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with FLINT; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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=============================================================================*/
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/******************************************************************************
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Copyright (C) 2011 Fredrik Johansson
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Copyright (C) 2013 Martin Lee
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******************************************************************************/
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#include <gmp.h>
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#include "flint.h"
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#include "nmod_vec.h"
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#include "nmod_poly.h"
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#include "nmod_mat.h"
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#include "ulong_extras.h"
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void
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_nmod_poly_reduce_matrix_mod_poly (nmod_mat_t A, const nmod_mat_t B,
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const nmod_poly_t f)
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{
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mp_ptr tmp1;
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slong n = f->length - 1;
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slong i, m = n_sqrt(n) + 1;
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nmod_mat_init(A, m, n, f->mod.n);
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A->rows[0][0] = UWORD(1);
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tmp1 = _nmod_vec_init(B->c - f->length + 1);
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for (i= 1; i < m; i++)
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_nmod_poly_divrem (tmp1, A->rows[i], B->rows[i], B->c, f->coeffs,
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f->length, f->mod);
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_nmod_vec_clear (tmp1);
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}
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void
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_nmod_poly_precompute_matrix (nmod_mat_t A, mp_srcptr poly1, mp_srcptr poly2,
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slong len2, mp_srcptr poly2inv, slong len2inv,
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nmod_t mod)
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{
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/* Set rows of A to powers of poly1 */
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slong i, n, m;
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n = len2 - 1;
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m = n_sqrt(n) + 1;
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A->rows[0][0] = UWORD(1);
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_nmod_vec_set(A->rows[1], poly1, n);
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for (i = 2; i < m; i++)
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_nmod_poly_mulmod_preinv(A->rows[i], A->rows[i - 1],
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n, poly1, n, poly2, len2, poly2inv, len2inv, mod);
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}
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void
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nmod_poly_precompute_matrix (nmod_mat_t A, const nmod_poly_t poly1,
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const nmod_poly_t poly2, const nmod_poly_t poly2inv)
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{
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slong len1 = poly1->length;
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slong len2 = poly2->length;
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slong len = len2 - 1;
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slong m = n_sqrt(len) + 1;
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mp_ptr ptr1;
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if (len2 == 0)
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{
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flint_printf("Exception (nmod_poly_precompute_matrix). Division by zero.\n");
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abort();
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}
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if (A->r != m || A->c != len)
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{
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flint_printf("Exception (nmod_poly_precompute_matrix). Wrong dimensions.\n");
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abort();
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}
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if (len2 == 1)
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{
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nmod_mat_zero(A);
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return;
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}
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ptr1 = _nmod_vec_init(len);
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if (len1 <= len)
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{
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flint_mpn_copyi(ptr1, poly1->coeffs, len1);
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flint_mpn_zero(ptr1 + len1, len - len1);
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}
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else
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{
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_nmod_poly_rem(ptr1, poly1->coeffs, len1,
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poly2->coeffs, len2, A->mod);
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}
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_nmod_poly_precompute_matrix (A, ptr1, poly2->coeffs, len2, poly2inv->coeffs,
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poly2inv->length, A->mod);
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_nmod_vec_clear (ptr1);
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}
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void
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_nmod_poly_compose_mod_brent_kung_precomp_preinv
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(mp_ptr res, mp_srcptr poly1, slong len1,
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const nmod_mat_t A, mp_srcptr poly3, slong len3,
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mp_srcptr poly3inv, slong len3inv, nmod_t mod)
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{
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nmod_mat_t B, C;
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mp_ptr t, h;
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slong i, n, m;
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n = len3 - 1;
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if (len3 == 1)
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return;
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if (len1 == 1)
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{
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res[0] = poly1[0];
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return;
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}
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if (len3 == 2)
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{
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res[0] = _nmod_poly_evaluate_nmod(poly1, len1, A->rows[1][0], mod);
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return;
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}
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m = n_sqrt(n) + 1;
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/* TODO check A*/
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nmod_mat_init(B, m, m, mod.n);
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nmod_mat_init(C, m, n, mod.n);
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h = _nmod_vec_init(n);
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t = _nmod_vec_init(n);
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/* Set rows of B to the segments of poly1 */
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for (i = 0; i < len1 / m; i++)
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_nmod_vec_set(B->rows[i], poly1 + i*m, m);
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_nmod_vec_set(B->rows[i], poly1 + i*m, len1 % m);
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nmod_mat_mul(C, B, A);
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/* Evaluate block composition using the Horner scheme */
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_nmod_vec_set(res, C->rows[m - 1], n);
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_nmod_poly_mulmod_preinv(h, A->rows[m - 1], n, A->rows[1], n,
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poly3, len3, poly3inv, len3inv,mod);
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for (i = m - 2; i >= 0; i--)
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{
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_nmod_poly_mulmod_preinv(t, res, n, h, n, poly3, len3,
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poly3inv, len3inv, mod);
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_nmod_poly_add(res, t, n, C->rows[i], n, mod);
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}
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_nmod_vec_clear(h);
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_nmod_vec_clear(t);
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nmod_mat_clear(B);
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nmod_mat_clear(C);
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}
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void
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nmod_poly_compose_mod_brent_kung_precomp_preinv(nmod_poly_t res,
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const nmod_poly_t poly1, const nmod_mat_t A,
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const nmod_poly_t poly3, const nmod_poly_t poly3inv)
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{
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slong len1 = poly1->length;
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slong len3 = poly3->length;
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slong len = len3 - 1;
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if (len3 == 0)
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{
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flint_printf("Exception (nmod_poly_compose_mod_brent_kung_precomp_preinv). Division by zero.\n");
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abort();
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}
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if (len1 >= len3)
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{
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flint_printf("Exception (nmod_poly_compose_mod_brent_kung_precomp_preinv). The degree of the \n"
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"first polynomial must be smaller than that of the modulus.\n");
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abort();
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}
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if (len1 == 0 || len3 == 1)
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{
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nmod_poly_zero(res);
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return;
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}
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if (len1 == 1)
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{
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nmod_poly_set(res, poly1);
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return;
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}
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if (res == poly3 || res == poly1 || res == poly3inv)
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{
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nmod_poly_t tmp;
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nmod_poly_init_preinv(tmp, res->mod.n, res->mod.ninv);
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nmod_poly_compose_mod_brent_kung_precomp_preinv(tmp, poly1, A,
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poly3, poly3inv);
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nmod_poly_swap(tmp, res);
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nmod_poly_clear(tmp);
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return;
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}
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nmod_poly_fit_length(res, len);
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_nmod_poly_compose_mod_brent_kung_precomp_preinv(res->coeffs,
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poly1->coeffs, len1, A, poly3->coeffs, len3,
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poly3inv->coeffs, poly3inv->length, res->mod);
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res->length = len;
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_nmod_poly_normalise(res);
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}
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