get the barycenter of the interval . concode_field_sep double lower concode_elem_sep double upper concode_field_sep double getSup concode_elem_sep double getSize concode_elem_sep double getInf concode_elem_sep double getMidPoint concode_elem_sep double getLower concode_elem_sep double getLength concode_elem_sep Location checkPoint concode_elem_sep double getUpper
double function ( ) { return 0.5 * ( lower + upper ) ; }