@ Override public double rand ( ) { if ( k - Math . floor ( k ) != 0.0 ) { throw new IllegalArgumentException ( "Gamma random number generator support only integer shape parameter." ) ; } double r = 0.0 ; for ( int i = 0 ; i < k ; i ++ ) { r += Math . log ( Math . random ( ) ) ; } r *= - theta ; return r ; }
Only support shape parameter k of integer .