/* mpc_tanh -- hyperbolic tangent of a complex number.

Copyright (C) 2008, 2009, 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_tanh (mpc_ptr rop, mpc_srcptr op, mpc_rnd_t rnd)

{

  /* tanh(op) = -i*tan(i*op) = conj(-i*tan(conj(-i*op))) */

  mpc_t z;

  mpc_t tan_z;

  int inex;

  /* z := conj(-i * op) and rop = conj(-i * tan(z)), in other words, we have

     to switch real and imaginary parts. Let us set them without copying

     significands. */

  mpc_realref (z)[0] = mpc_imagref (op)[0];

  mpc_imagref (z)[0] = mpc_realref (op)[0];

  mpc_realref (tan_z)[0] = mpc_imagref (rop)[0];

  mpc_imagref (tan_z)[0] = mpc_realref (rop)[0];

  inex = mpc_tan (tan_z, z, MPC_RND (MPC_RND_IM (rnd), MPC_RND_RE (rnd)));

  /* tan_z and rop parts share the same significands, copy the rest now. */

  mpc_realref (rop)[0] = mpc_imagref (tan_z)[0];

  mpc_imagref (rop)[0] = mpc_realref (tan_z)[0];

  /* swap inexact flags for real and imaginary parts */

  return MPC_INEX (MPC_INEX_IM (inex), MPC_INEX_RE (inex));

}