(!******************************************************
   Mosel Example Problems
   ======================

   file f1connect.mos
   ``````````````````
   Planning flight connections at a hub

   An airline has 6 planes landing within 90 minutes. During
   the following hour, these planes must travel to 6 new
   destinations. How should the incoming planes be used for
   the new departures to minimize the number of passengers who
   must change planes during the connection?

   For infeasible departure assignments, we assign a large negative
   number for how many passengers will remain on the plane during
   the connection. By maximizing the number of passengers who stay
   on the plane, this eliminates these infeasible departures.
   
   (c) 2008 Fair Isaac Corporation
       author: S. Heipcke, Mar. 2002
*******************************************************!)

model "F-1 Flight connections"
 uses "mmxprs"

 declarations
  PLANES = 1..6                         ! Set of airplanes
  
  PASS: array(PLANES,PLANES) of integer ! Passengers with flight connections
  
  cont: array(PLANES,PLANES) of mpvar   ! 1 if flight i continues to j
 end-declarations

 initializations from 'f1connect.dat'
  PASS
 end-initializations

! Objective: number of passengers on connecting flights
 Transfer:= sum(i,j in PLANES) PASS(i,j)*cont(i,j)

! One incoming and one outgoing flight per plane
 forall(i in PLANES) sum(j in PLANES) cont(i,j) = 1
 forall(j in PLANES) sum(i in PLANES) cont(i,j) = 1

 forall(i,j in PLANES) cont(i,j) is_binary

! Solve the problem: maximize the number of passengers staying on board
 maximize(Transfer)
 
! Solution printing
 writeln("Passengers staying on board: ", getobjval)
 forall(i in PLANES)
 writeln(i, " -> ", getsol(sum(j in PLANES) j*cont(i,j)), " (",
         getsol(sum(j in PLANES) PASS(i,j)*cont(i,j)), ")")
 
end-model