107 lines
2.8 KiB
C
107 lines
2.8 KiB
C
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/*============================================================================
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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) 2012 Sebastian Pancratz
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******************************************************************************/
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#include "fmpz_mod_poly.h"
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#include "padic_poly.h"
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/*
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TODO: Move this bit of code into "padic".
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*/
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static void __padic_reduce(fmpz_t u, slong *v, slong N, const padic_ctx_t ctx)
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{
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if (!fmpz_is_zero(u))
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{
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if (*v < N)
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{
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int alloc;
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fmpz_t pow;
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alloc = _padic_ctx_pow_ui(pow, N - *v, ctx);
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fmpz_mod(u, u, pow);
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if (alloc)
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fmpz_clear(pow);
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}
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else
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{
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fmpz_zero(u);
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*v = 0;
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}
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}
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}
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void _padic_poly_compose_pow(fmpz *rop, slong *rval, slong N,
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const fmpz *op, slong val, slong len, slong k,
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const padic_ctx_t ctx)
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{
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if (k == 1)
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{
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if (rop != op)
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{
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_fmpz_vec_set(rop, op, len);
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*rval = val;
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}
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}
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else if (len == 1)
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{
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fmpz_set(rop, op);
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*rval = val;
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__padic_reduce(rop, rval, N, ctx);
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}
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else
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{
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slong i, j, h;
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for (i = len - 1, j = (len - 1) * k ; i >= 0; i--, j -= k)
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{
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fmpz_set(rop + j, op + i);
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if (i)
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for (h = 1; h < k; h++)
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fmpz_zero(rop + (j - h));
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}
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*rval = val;
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}
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}
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void padic_poly_compose_pow(padic_poly_t rop, const padic_poly_t op, slong k,
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const padic_ctx_t ctx)
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{
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const slong len = op->length;
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const slong lenr = (len - 1) * k + 1;
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if (len == 0)
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{
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padic_poly_zero(rop);
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}
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else
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{
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padic_poly_fit_length(rop, lenr);
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_padic_poly_compose_pow(rop->coeffs, &(rop->val), rop->N,
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op->coeffs, op->val, op->length, k, ctx);
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_padic_poly_set_length(rop, lenr);
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}
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}
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