/* mpc_mul_i -- Multiply a complex number by plus or minus i.
Copyright (C) INRIA, 2005, 2009, 2010
This file is part of the MPC Library.
The MPC Library 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 2.1 of the License, or (at your
option) any later version.
The MPC Library 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 the MPC Library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA. */
#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_RE (a), MPC_IM (a));
else
{
mpfr_set (MPC_RE (a), MPC_IM (b), GMP_RNDN);
mpfr_set (MPC_IM (a), MPC_RE (b), GMP_RNDN);
}
if (sign >= 0)
MPFR_CHANGE_SIGN (MPC_RE (a));
else
MPFR_CHANGE_SIGN (MPC_IM (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_IM (b), MPC_RND_RE (rnd));
inex_im = mpfr_set (MPC_IM (a), MPC_RE (b), MPC_RND_IM (rnd));
}
else
{
inex_re = mpfr_set (tmp, MPC_IM (b), MPC_RND_RE (rnd));
inex_im = mpfr_neg (MPC_IM (a), MPC_RE (b), MPC_RND_IM (rnd));
}
mpfr_clear (MPC_RE (a));
MPC_RE (a)[0] = tmp [0];
}
else
if (sign >= 0)
{
inex_re = mpfr_neg (MPC_RE (a), MPC_IM (b), MPC_RND_RE (rnd));
inex_im = mpfr_set (MPC_IM (a), MPC_RE (b), MPC_RND_IM (rnd));
}
else
{
inex_re = mpfr_set (MPC_RE (a), MPC_IM (b), MPC_RND_RE (rnd));
inex_im = mpfr_neg (MPC_IM (a), MPC_RE (b), MPC_RND_IM (rnd));
}
}
return MPC_INEX(inex_re, inex_im);
}