$Title A Transportation Problem (TRNSPORT,SEQ=1) $Ontext This program is a modified version of trnsport.gms and illustrates use of reading data from a GDX file during execution time $Offtext Sets i canning plants j markets; $gdxin Trnsport.gdx $load i j Parameters a(i) capacity of plant i in cases b(j) demand at market j in cases d(i,j) distance in thousands of miles ; Scalar f freight in dollars per case per thousand miles; execute_load 'Trnsport.gdx' a,b,d,f; Parameter c(i,j) transport cost in thousands of dollars per case ; c(i,j) = f * d(i,j) / 1000 ; Variables x(i,j) shipment quantities in cases z total transportation costs in thousands of dollars ; Positive Variable x ; Equations cost define objective function supply(i) observe supply limit at plant i demand(j) satisfy demand at market j ; cost .. z =e= sum((i,j), c(i,j)*x(i,j)) ; supply(i) .. sum(j, x(i,j)) =l= a(i) ; demand(j) .. sum(i, x(i,j)) =g= b(j) ; Model transport /all/ ; Solve transport using lp minimizing z ; Display x.l, x.m ;