! Generic set-based LINGO Transportation model, (ParkingDense.lng)
  applied to a parking spot to apartment assignment problem;
! This model is meant to be used with ParkingDensex.xlsx;
! Keywords: Transportation model, Parking;
 SPOT: CAP; ! Each group of spots has a capacity;
 APT: DEM;  ! Each apartment group has a demand;
 SXA( SPOT, APT): COST, ASSIGN; ! Each combination has a cost. 
   We want to determine the number to assign to each combination,
   so as to minimize the cost (i.e., distance traveled);
DATA: ! This is the dense case, all combinations are possible; SPOT = @ole(); ! Get list of parking spots from currently open spreadsheet; CAP = @ole(); ! Get capacity. Will use open spreadsheet if no name; APT = @ole(); ! Get list of apartments needing parking spots; DEM = @ole(); ! Get demand of each apartment block; COST = @ole(); ! and the Cost (distance) of each combination; ENDDATA !---------------------------------------------------------; ! Minimize total distance traveled; [obj] MIN = @SUM(SXA(i,j): COST(i,j) * ASSIGN(i,j)); ! Capacity constraints for each group of spots; @FOR( SPOT( i): @SUM( SXA(i,J): ASSIGN( I, J)) <= CAP( I); ); ! Demand constraints for each group of apartments; @FOR( APT( J): @SUM( SXA( I,j): ASSIGN( I, J)) = DEM( J); ); DATA: ! Send the results back to the spread sheet to the range name matching variable name; @OLE() = ASSIGN; @OLE()= obj; ENDDATA