question: public static void checkFinite ( final double [ ] val ) throws MathIllegalArgumentException { for ( int i = 0 ; i < val . length ; i ++ ) { final double x = val [ i ] ; if ( Double . isInfinite ( x ) || Double . isNaN ( x ) ) { throw new MathIllegalArgumentException ( LocalizedCoreFormats . NOT_FINITE_NUMBER , x ) ; } } }
target:  Check that all the elements are real numbers.