1 /* mpc_atanh -- inverse hyperbolic tangent of a complex number. 2 3 Copyright (C) 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_atanh (mpc_ptr rop, mpc_srcptr op, mpc_rnd_t rnd) 25 { 26 /* atanh(op) = -i*atan(i*op) */ 27 int inex; 28 mpfr_t tmp; 29 mpc_t z, a; 30 31 mpc_realref (z)[0] = mpc_imagref (op)[0]; 32 mpc_imagref (z)[0] = mpc_realref (op)[0]; 33 MPFR_CHANGE_SIGN (mpc_realref (z)); 34 35 /* Note reversal of precisions due to later multiplication by -i */ 36 mpc_init3 (a, MPC_PREC_IM(rop), MPC_PREC_RE(rop)); 37 38 inex = mpc_atan (a, z, 39 MPC_RND (INV_RND (MPC_RND_IM (rnd)), MPC_RND_RE (rnd))); 40 41 /* change a to -i*a, i.e., x+i*y to y-i*x */ 42 tmp[0] = mpc_realref (a)[0]; 43 mpc_realref (a)[0] = mpc_imagref (a)[0]; 44 mpc_imagref (a)[0] = tmp[0]; 45 MPFR_CHANGE_SIGN (mpc_imagref (a)); 46 47 mpc_set (rop, a, rnd); 48 49 mpc_clear (a); 50 51 return MPC_INEX (MPC_INEX_IM (inex), -MPC_INEX_RE (inex)); 52 } 53