merged inverse trigonometric and inverse hyperbolic functions from branch

feature-inverse-trigo


git-svn-id: svn://scm.gforge.inria.fr/svn/mpc/trunk@685 211d60ee-9f03-0410-a15a-8952a2c7a4e4

1 files changed, 68 insertions, 0 deletions

diff --git a/src/acosh.c b/src/acosh.c
new file mode 100644
index 0000000..3bd1439
--- /dev/null
+++ b/src/acosh.c
@@ -0,0 +1,68 @@
+/* mpc_acosh -- inverse hyperbolic cosine of a complex number.
+
+Copyright (C) 2009 Philippe Th\'eveny
+
+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_acosh (mpc_ptr rop, mpc_srcptr op, mpc_rnd_t rnd)
+{
+  /* acosh(z) =
+      NaN + i*NaN, if z=0+i*NaN
+     -i*acos(z), if sign(Im(z)) = -
+      i*acos(z), if sign(Im(z)) = +  
+  */
+  mpfr_t tmp;
+  int inex;
+
+  if (mpfr_zero_p (MPC_RE (op)) && mpfr_nan_p (MPC_IM (op)))
+    {
+      mpfr_set_nan (MPC_RE (rop));
+      mpfr_set_nan (MPC_IM (rop));
+      return 0;
+    }
+  
+  if (mpfr_signbit (MPC_IM (op)))
+    {
+      inex = mpc_acos (rop, op,
+                       RNDC (INV_RND (MPC_RND_IM (rnd)), MPC_RND_RE (rnd)));
+
+      /* change rop to -i*rop */
+      tmp[0] = MPC_RE (rop)[0];
+      MPC_RE (rop)[0] = MPC_IM (rop)[0];
+      MPC_IM (rop)[0] = tmp[0];
+      MPFR_CHANGE_SIGN (MPC_IM (rop));
+      inex = MPC_INEX (MPC_INEX_IM (inex), -MPC_INEX_RE (inex));
+    }
+  else
+    {
+      inex = mpc_acos (rop, op,
+                       RNDC (MPC_RND_IM (rnd), INV_RND(MPC_RND_RE (rnd))));
+
+      /* change rop to i*rop */
+      tmp[0] = MPC_RE (rop)[0];
+      MPC_RE (rop)[0] = MPC_IM (rop)[0];
+      MPC_IM (rop)[0] = tmp[0];
+      MPFR_CHANGE_SIGN (MPC_RE (rop));
+      inex = MPC_INEX (-MPC_INEX_IM (inex), MPC_INEX_RE (inex));
+    }
+
+  return inex;
+}