111 lines
3.2 KiB
C
111 lines
3.2 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 "qadic.h"
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void _qadic_log(fmpz *z, const fmpz *y, slong v, slong len,
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const fmpz *a, const slong *j, slong lena,
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const fmpz_t p, slong N, const fmpz_t pN)
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{
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if (N < (WORD(1) < 10) / (slong) fmpz_bits(p))
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{
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_qadic_log_rectangular(z, y, v, len, a, j, lena, p, N, pN);
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}
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else
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{
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_qadic_log_balanced(z, y, len, a, j, lena, p, N, pN);
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}
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}
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int qadic_log(qadic_t rop, const qadic_t op, const qadic_ctx_t ctx)
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{
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const fmpz *p = (&ctx->pctx)->p;
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const slong d = qadic_ctx_degree(ctx);
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const slong N = qadic_prec(rop);
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const slong len = op->length;
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if (op->val < 0)
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{
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return 0;
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}
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else
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{
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fmpz *x;
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fmpz_t pN;
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int alloc, ans;
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x = _fmpz_vec_init(len + 1);
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alloc = _padic_ctx_pow_ui(pN, N, &ctx->pctx);
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/* Set x := (1 - op) mod p^N */
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fmpz_pow_ui(x + len, p, op->val);
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_fmpz_vec_scalar_mul_fmpz(x, op->coeffs, len, x + len);
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fmpz_sub_ui(x, x, 1);
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_fmpz_vec_neg(x, x, len);
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_fmpz_vec_scalar_mod_fmpz(x, x, len, pN);
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if (_fmpz_vec_is_zero(x, len))
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{
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padic_poly_zero(rop);
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ans = 1;
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}
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else
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{
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const slong v = _fmpz_vec_ord_p(x, len, p);
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if (v >= 2 || (*p != WORD(2) && v >= 1))
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{
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if (v >= N)
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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, d);
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_qadic_log(rop->coeffs, x, v, len,
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ctx->a, ctx->j, ctx->len, p, N, pN);
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rop->val = 0;
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_padic_poly_set_length(rop, d);
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_padic_poly_normalise(rop);
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padic_poly_canonicalise(rop, p);
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}
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ans = 1;
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}
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else
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{
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ans = 0;
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}
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}
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_fmpz_vec_clear(x, len + 1);
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if (alloc)
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fmpz_clear(pN);
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return ans;
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}
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}
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