GroovX: src/mtx/mathspecial.cc Source File

00001 
00004 
00005 //
00006 // Copyright (c) 2001-2004 California Institute of Technology
00007 // Copyright (c) 2004-2007 University of Southern California
00008 // Rob Peters <rjpeters at usc dot edu>
00009 //
00010 // created: Thu Mar  8 16:28:26 2001 (split from num.h)
00011 // commit: $Id: mathspecial.cc 10065 2007-04-12 05:54:56Z rjpeters $
00012 // $HeadURL: file:///lab/rjpeters/svnrepo/code/trunk/groovx/src/mtx/mathspecial.cc $
00013 //
00014 // --------------------------------------------------------------------
00015 //
00016 // This file is part of GroovX.
00017 //   [http://ilab.usc.edu/rjpeters/groovx/]
00018 //
00019 // GroovX is free software; you can redistribute it and/or modify it
00020 // under the terms of the GNU General Public License as published by
00021 // the Free Software Foundation; either version 2 of the License, or
00022 // (at your option) any later version.
00023 //
00024 // GroovX is distributed in the hope that it will be useful, but
00025 // WITHOUT ANY WARRANTY; without even the implied warranty of
00026 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00027 // General Public License for more details.
00028 //
00029 // You should have received a copy of the GNU General Public License
00030 // along with GroovX; if not, write to the Free Software Foundation,
00031 // Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
00032 //
00034 
00035 #ifndef GROOVX_PKGS_MTX_MATHSPECIAL_CC_UTC20050626084022_DEFINED
00036 #define GROOVX_PKGS_MTX_MATHSPECIAL_CC_UTC20050626084022_DEFINED
00037 
00038 #include "mathspecial.h"
00039 
00040 #include "rutz/trace.h"
00041 
00042 double dash::detail::gammaln_engine(const double xx)
00043 {
00044 GVX_TRACE("dash::detail::gammaln_engine");
00045 
00046   static const double cof[6] =
00047     {
00048       76.18009172947146,     -86.50532032941677,
00049       24.01409824083091,     -1.231738572450155,
00050       0.1208650973866179e-2, -0.5395239384953e-5
00051     };
00052 
00053   double ser=1.000000000190015;
00054 
00055   for (int j = 0; j < 5; ++j)
00056     ser += cof[j]/(xx+j+1);
00057 
00058   const double tmp1 = xx+5.5;
00059   const double tmp = tmp1 - (xx+0.5)*log(tmp1);
00060 
00061   return -tmp+log(2.5066282746310005*ser/xx);
00062 }
00063 
00064 static const char __attribute__((used)) vcid_groovx_pkgs_mtx_mathspecial_cc_utc20050626084022[] = "$Id: mathspecial.cc 10065 2007-04-12 05:54:56Z rjpeters $ $HeadURL: file:
00065 #endif // !GROOVX_PKGS_MTX_MATHSPECIAL_CC_UTC20050626084022_DEFINED