generates a poisson distributed random number . the poisson distribution is definded by the number lambda . the distribution has mean lambda and standard deviation of math.sqrt lambda . if lambda is smaller than 200 the value is determined by cumulative statistics , otherwise an approximation is used . time measurements showed that the approximation used here outperforms the implementation in matlab 2008 . concode_field_sep Random rand concode_elem_sep double stirlingConst concode_field_sep int poissonRandomNumberSmall concode_elem_sep void main concode_elem_sep double logfactorial concode_elem_sep int poissonRandomNumberBig
int function ( double arg0 ) { if ( arg0 < 200 ) { return poissonRandomNumberSmall ( arg0 ) ; } else { return poissonRandomNumberBig ( arg0 ) ; } }