MODEL:
 ! One machine job selection;
SETS:

 ! There are six jobs each of which has a Due Date,
   Processing Time, Value, and a flag variable Y 
   indicating if the job has been selected.;
  JOB/1..6/: ! Each job has a...;
   DD,  ! Due date;
   PT,  ! Processing time;
   VAL, ! Value if job is selected;
   Y;   ! = 1 if job is selected, else 0;
 ENDSETS

 DATA:
  VAL = 9  2  4  2  4  6;
  DD =  9  3  6  5  7  2;
  PT =  5  2  4  3  1  2;
 ENDDATA

  ! Maximize the total value of the jobs taken;
  MAX = TVAL;
  TVAL = @SUM( JOB: VAL * Y);

  ! For the jobs we do, we do in due date order;
  @FOR( JOB( J):

    ! Only jobs with earlier due dates can 
      precede job J, and jobs must be completed 
      by their due dates;
    @SUM( JOB( I)| DD( I) #LT# DD( J) #OR#
     (  DD( I) #EQ# DD( J) #AND# I #LE# J):
      PT( I) * Y( I)) <= DD( J);

   ! Make the Y's binary;
    @BIN( Y);
  );
END