proc optmodel;

set Plant = {"P1", "P2"};
set Center = {"CA", "CB"};
set Region = {"R1", "R2", "R3"};

number capacity{Plant} = [100 125];
number demand{Region} = [25 95 80];

number incost{Plant, Center} = [ 
190 210
185 205
];
number outcost{Center, Region} = [ 
175 180 165
235 130 145
];

var inflow{Plant, Center} >= 0;
var outflow{Center, Region} >= 0;

minimize z = sum{i in Plant, k in Center}inflow[i,k]*incost[i,k]+
sum{k in Center, j in Region}outflow[k,j]*outcost[k,j]
;

con capacitycon{i in Plant}: sum{k in Center}inflow[i,k] <= capacity[i];
con demandcon{j in Region}: sum{k in Center}outflow[k,j] >= demand[j];
con balancecon{k in Center}: sum{i in Plant}inflow[i,k] = sum{j in Region}outflow[k,j];

solve;
print z inflow outflow;
expand;
quit;