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/*
Copyright (C) 2011, 2012 Sebastian Pancratz
This file is part of FLINT.
FLINT is free software: you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License (LGPL) as published
by the Free Software Foundation; either version 3 of the License, or
(at your option) any later version. See <https://www.gnu.org/licenses/>.
*/
#include "padic.h"
void padic_pow_si(padic_t rop, const padic_t op, slong e, const padic_ctx_t ctx)
{
if (e == 0)
{
padic_one(rop);
}
else if (padic_is_zero(op) || e * padic_val(op) >= padic_prec(rop))
{
padic_zero(rop);
}
else
{
fmpz_t pow;
int alloc;
padic_val(rop) = e * padic_val(op);
alloc = _padic_ctx_pow_ui(pow, padic_prec(rop) - padic_val(rop), ctx);
if (e > 0)
{
fmpz_powm_ui(padic_unit(rop), padic_unit(op), e, pow);
}
else /* e < 0 */
{
/* u^{-1} to precision (N - v) */
_padic_inv(padic_unit(rop), padic_unit(op),
ctx->p, padic_prec(rop) - padic_val(rop));
fmpz_powm_ui(padic_unit(rop), padic_unit(rop), -e, pow);
}
if (alloc)
fmpz_clear(pow);
}
}