prod.mod
Sample model from the AMPL book
set P;
param a {j in P};
param b;
param c {j in P};
param u {j in P};
var X {j in P};
maximize Total_Profit: sum {j in P} c[j] * X[j];
subject to Time: sum {j in P} (1/a[j]) * X[j] <= b;
subject to Limit {j in P}: 0 <= X[j] <= u[j];