question: protected String num2ShortID ( int num , char [ ] IDChars , int IDWidth ) { char ID [ ] = new char [ IDWidth ] ; int i ; for ( i = IDWidth - 1 ; i >= 0 ; i -- ) { ID [ i ] = IDChars [ num % IDChars . length ] ; num = num / IDChars . length - 1 ; if ( num < 0 ) { break ; } } for ( i -- ; i >= 0 ; i -- ) { ID [ i ] = ' ' ; } return new String ( ID ) ; }
target:  Method for generating indices for the confusion matrix.