diff options
Diffstat (limited to 'src/elementaryFunctions/acosh/cacoshs.c')
| -rw-r--r-- | src/elementaryFunctions/acosh/cacoshs.c | 37 |
1 files changed, 25 insertions, 12 deletions
diff --git a/src/elementaryFunctions/acosh/cacoshs.c b/src/elementaryFunctions/acosh/cacoshs.c index 6fa0ebf3..b90de13d 100644 --- a/src/elementaryFunctions/acosh/cacoshs.c +++ b/src/elementaryFunctions/acosh/cacoshs.c @@ -1,18 +1,31 @@ /* -** -*- C -*- -** -** cacoshs.c -** Made by Bruno JOFRET <bruno.jofret@inria.fr> -** -** Started on Fri Jan 5 11:29:45 2007 jofret -** Last update Thu Sep 6 10:44:09 2007 bruno -** -** Copyright INRIA 2007 -*/ + * Scilab ( http://www.scilab.org/ ) - This file is part of Scilab + * Copyright (C) 2007-2008 - INRIA - Bruno JOFRET + * + * This file must be used under the terms of the CeCILL. + * This source file is licensed as described in the file COPYING, which + * you should have received as part of this distribution. The terms + * are also available at + * http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt + * + */ + +// METHOD +// based on the formula : +// +// acosh(z) = sign(-imag(acos(z)) i acos(z) +// +// sign(x) = 1 if x >= 0 +// | -1 if x < 0 #include "acosh.h" +#include "acos.h" + +#define localSign(x) x >= 0 ? 1.0f : -1.0f floatComplex cacoshs(floatComplex z) { - /* FIXME: Dummy... */ - return z; + floatComplex acos_z = cacoss(z); + float sign = localSign(-cimags(acos_z)); + + return FloatComplex(-sign * cimags(acos_z), sign * creals(acos_z)); } |