At Sat, 12 Aug 2006 08:37:12 +0200, Marco Maggi wrote: > for some values of the operand I get different results > from 'acosh' when using GSL (1.8), Guile (1.8) and GNU > Octave (2.1.63). Other functions give me different results, > too. Below is the output of my tests. I am not at all a > math expert.
Hello, There are different branch cut conventions used by different programs. acosh or other inverse functions are mutiple-valued functions so the result is not uniquely defined. GSL uses one of the two common conventions (W.Kahan's) because it has better consistency with IEEE arithmetic. It is also used by Common Lisp -- see the GSL Reference manual for details and references. The others are using a different convention (Abramowitz & Stegun). As such, all the answers are correct. -- best regards, Brian Gough Network Theory Ltd, Publishing the GSL Manual - http://www.network-theory.co.uk/gsl/manual/ _______________________________________________ Help-gsl mailing list Help-gsl@gnu.org http://lists.gnu.org/mailman/listinfo/help-gsl
