Impala Documentation

template<class DstArrayT, class SrcArrayT>

double Impala::Core::Feature::IntWeibullNgbPnLoop< DstArrayT, SrcArrayT >::gammaFunc ( double xx ) const [inline]

Definition at line 255 of file IntWeibullNgbPnLoop.h.

00256     {
00257         double x,y,tmp,ser;
00258         static double cof[6] =
00259             {
00260                 76.18009172947146, -86.50532032941677,
00261                 24.01409824083091, -1.231739572450155,
00262                 0.1208650973866179e-2, -0.5395239384953e-5
00263             };
00264         
00265         int j;
00266         y=x=xx;
00267         tmp=x+5.5;
00268         tmp -= (x+0.5)*log(tmp);
00269         ser=1.000000000190015;
00270         for (j=0;j<=5;j++)
00271             ser += cof[j]/++y;
00272         xx = -tmp+log(2.5066282746310005*ser/x);
00273         return exp(xx);
00274     }