63 lines
2.0 KiB
C
63 lines
2.0 KiB
C
/*=============================================================================
|
|
|
|
This file is part of FLINT.
|
|
|
|
FLINT is free software; you can redistribute it and/or modify
|
|
it under the terms of the GNU General Public License as published by
|
|
the Free Software Foundation; either version 2 of the License, or
|
|
(at your option) any later version.
|
|
|
|
FLINT is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with FLINT; if not, write to the Free Software
|
|
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
|
|
|
|
=============================================================================*/
|
|
/******************************************************************************
|
|
|
|
Copyright (C) 2011, 2012 Sebastian Pancratz
|
|
|
|
******************************************************************************/
|
|
|
|
#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 ceil((N - v e) / -e) */
|
|
_padic_inv(padic_unit(rop), padic_unit(op),
|
|
ctx->p, (padic_prec(rop) - padic_val(rop) + (-e - 1)) / -e);
|
|
|
|
fmpz_powm_ui(padic_unit(rop), padic_unit(rop), -e, pow);
|
|
}
|
|
if (alloc)
|
|
fmpz_clear(pow);
|
|
}
|
|
}
|
|
|