%data : plants set, centers set[1], routes set[2]
%data : c[routes] , s[plants] , d[centers]
%display nonZeros

variables:
 	x[routes]: real[0..];
objectives:
 	costs: sum{ [i,j] in routes : c[i,j]*x[i,j] } ->min;
constraints:
 	supplies {i in plants : sum{j in routes *> [i,*] : x[i,j]} = s[i];}
 	demands  {j in centers: sum{i in routes *> [*,j] : x[i,j]} <= d[j];} 
 
 
