question: private static double distance ( Problem problem , Solution a , Solution b , double power ) { double distance = 0.0 ; for ( int i = 0 ; i < problem . getNumberOfObjectives ( ) ; i ++ ) { distance += Math . pow ( Math . abs ( a . getObjective ( i ) - b . getObjective ( i ) ) , power ) ; } return Math . pow ( distance , 1.0 / power ) ; }
target:  Returns the distance in objective space between the two solutions.