```! Standard fixed charge transportation problem; ! Keywords: Fixed charge, Transportation problem; SETS: source: capacity, fixedcost, open; dest: demand; sxd( source, dest): costpu, ship; ENDSETSDATA: ! Sources of production; source = PLANT01 PLANT02 PLANT03; ! Capacity of each source; capacity = 1200 1800 1500; ! Fixed cost if we ship anything from source; fixedcost= 1800 1900 1700; ! Destinations; dest = CUST01 CUST02 CUST03 CUST04; ! Demand at each destination; demand = 600 700 500 550; ! Cost per unit shipped from each source to each destination; costpu = 9 8 6 7 5 7 8 6 6 5 9 8; ENDDATA ! Variables: open( s) = 1 is source s is used (or open), else 0, i.e., it is a binary variable, ship( s, d) = amount shipped from source s to destination d; ! LINGO assumes by default that all variables are >= 0; ! minimize fixed cost + shipping costs; min = fctot + sctot; fctot = @SUM( source( s): fixedcost( s)* open(s)); sctot = @SUM( sxd( s, d) : costpu( s, d)* ship( s, d)); @FOR( source( s): @bin( open( s)); ! Source is either used (1) or not used (0); ! Cannot ship more than installed capacity from source s; @SUM( sxd( s, d): ship( s, d)) <= capacity( s)* open(s); ); @FOR( dest( d): ! Must satisfy demand at each destination d; @SUM( sxd( s, d): ship( s, d)) = demand( d); ); ```