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/* mpc_mul_i -- Multiply a complex number by plus or minus i.
Copyright (C) 2005, 2009, 2010, 2011, 2012 INRIA
This file is part of GNU MPC.
GNU MPC is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the
Free Software Foundation; either version 3 of the License, or (at your
option) any later version.
GNU MPC 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 Lesser General Public License for
more details.
You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see http://www.gnu.org/licenses/ .
*/
#include "mpc-impl.h"
int
mpc_mul_i (mpc_ptr a, mpc_srcptr b, int sign, mpc_rnd_t rnd)
/* if sign is >= 0, multiply by i, otherwise by -i */
{
int inex_re, inex_im;
mpfr_t tmp;
/* Treat the most probable case of compatible precisions first */
if ( MPC_PREC_RE (b) == MPC_PREC_IM (a)
&& MPC_PREC_IM (b) == MPC_PREC_RE (a))
{
if (a == b)
mpfr_swap (mpc_realref (a), mpc_imagref (a));
else
{
mpfr_set (mpc_realref (a), mpc_imagref (b), MPFR_RNDN);
mpfr_set (mpc_imagref (a), mpc_realref (b), MPFR_RNDN);
}
if (sign >= 0)
MPFR_CHANGE_SIGN (mpc_realref (a));
else
MPFR_CHANGE_SIGN (mpc_imagref (a));
inex_re = 0;
inex_im = 0;
}
else
{
if (a == b)
{
mpfr_init2 (tmp, MPC_PREC_RE (a));
if (sign >= 0)
{
inex_re = mpfr_neg (tmp, mpc_imagref (b), MPC_RND_RE (rnd));
inex_im = mpfr_set (mpc_imagref (a), mpc_realref (b), MPC_RND_IM (rnd));
}
else
{
inex_re = mpfr_set (tmp, mpc_imagref (b), MPC_RND_RE (rnd));
inex_im = mpfr_neg (mpc_imagref (a), mpc_realref (b), MPC_RND_IM (rnd));
}
mpfr_clear (mpc_realref (a));
mpc_realref (a)[0] = tmp [0];
}
else
if (sign >= 0)
{
inex_re = mpfr_neg (mpc_realref (a), mpc_imagref (b), MPC_RND_RE (rnd));
inex_im = mpfr_set (mpc_imagref (a), mpc_realref (b), MPC_RND_IM (rnd));
}
else
{
inex_re = mpfr_set (mpc_realref (a), mpc_imagref (b), MPC_RND_RE (rnd));
inex_im = mpfr_neg (mpc_imagref (a), mpc_realref (b), MPC_RND_IM (rnd));
}
}
return MPC_INEX(inex_re, inex_im);
}
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