1 /* mpc_tanh -- hyperbolic tangent of a complex number. 2 3 Copyright (C) 2008, 2009, 2011, 2012 INRIA 4 5 This file is part of GNU MPC. 6 7 GNU MPC is free software; you can redistribute it and/or modify it under 8 the terms of the GNU Lesser General Public License as published by the 9 Free Software Foundation; either version 3 of the License, or (at your 10 option) any later version. 11 12 GNU MPC is distributed in the hope that it will be useful, but WITHOUT ANY 13 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 14 FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for 15 more details. 16 17 You should have received a copy of the GNU Lesser General Public License 18 along with this program. If not, see http://www.gnu.org/licenses/ . 19 */ 20 21 #include "mpc-impl.h" 22 23 int 24 mpc_tanh (mpc_ptr rop, mpc_srcptr op, mpc_rnd_t rnd) 25 { 26 /* tanh(op) = -i*tan(i*op) = conj(-i*tan(conj(-i*op))) */ 27 mpc_t z; 28 mpc_t tan_z; 29 int inex; 30 31 /* z := conj(-i * op) and rop = conj(-i * tan(z)), in other words, we have 32 to switch real and imaginary parts. Let us set them without copying 33 significands. */ 34 mpc_realref (z)[0] = mpc_imagref (op)[0]; 35 mpc_imagref (z)[0] = mpc_realref (op)[0]; 36 mpc_realref (tan_z)[0] = mpc_imagref (rop)[0]; 37 mpc_imagref (tan_z)[0] = mpc_realref (rop)[0]; 38 39 inex = mpc_tan (tan_z, z, MPC_RND (MPC_RND_IM (rnd), MPC_RND_RE (rnd))); 40 41 /* tan_z and rop parts share the same significands, copy the rest now. */ 42 mpc_realref (rop)[0] = mpc_imagref (tan_z)[0]; 43 mpc_imagref (rop)[0] = mpc_realref (tan_z)[0]; 44 45 /* swap inexact flags for real and imaginary parts */ 46 return MPC_INEX (MPC_INEX_IM (inex), MPC_INEX_RE (inex)); 47 } 48