arb/arb_poly/normalise.c
2012-04-07 20:38:35 +02:00

47 lines
1.6 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) 2012 Fredrik Johansson
******************************************************************************/
#include "arb_poly.h"
void
_arb_poly_normalise(fmpz * coeffs, fmpz_t exp, fmpz_t rad, long len, long bits)
{
if (len != 0)
{
long b, shift;
b = _fmpz_vec_max_bits(coeffs, len);
b = FLINT_ABS(b);
shift = FLINT_MAX(b - bits, 0);
if (shift > 0)
{
_fmpz_vec_scalar_tdiv_q_2exp(coeffs, coeffs, len, shift);
fmpz_cdiv_q_2exp(rad, rad, shift); /* must round up */
fmpz_add_ui(rad, rad, 1UL); /* error from rounding */
fmpz_add_ui(exp, exp, shift);
}
}
}