63 lines
2.0 KiB
C
63 lines
2.0 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) 2011, 2012 Sebastian Pancratz
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******************************************************************************/
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#include "padic.h"
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void padic_pow_si(padic_t rop, const padic_t op, slong e, const padic_ctx_t ctx)
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{
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if (e == 0)
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{
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padic_one(rop);
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}
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else if (padic_is_zero(op) || e * padic_val(op) >= padic_prec(rop))
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{
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padic_zero(rop);
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}
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else
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{
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fmpz_t pow;
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int alloc;
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padic_val(rop) = e * padic_val(op);
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alloc = _padic_ctx_pow_ui(pow, padic_prec(rop) - padic_val(rop), ctx);
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if (e > 0)
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{
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fmpz_powm_ui(padic_unit(rop), padic_unit(op), e, pow);
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}
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else /* e < 0 */
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{
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/* u^{-1} to precision ceil((N - v e) / -e) */
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_padic_inv(padic_unit(rop), padic_unit(op),
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ctx->p, (padic_prec(rop) - padic_val(rop) + (-e - 1)) / -e);
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fmpz_powm_ui(padic_unit(rop), padic_unit(rop), -e, pow);
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}
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if (alloc)
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fmpz_clear(pow);
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}
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}
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