set INs;    # inputs
set OUTs;   # outputs

param cost {INs} > 0;
param in_min {INs} >= 0;
param in_max {j in INs} >= in_min[j];

param out_min {OUTs} >= 0;
param out_max {i in OUTs} >= out_min[i];

param io {INs,OUTs} >= 0;

var X {j in INs} >= in_min[j], <= in_max[j];

minimize total_cost:  sum {j in INs} cost[j] * X[j];

subject to outputs {i in OUTs}:
   out_min[i] <= sum {j in INs} io[j,i] * X[j] <= out_max[i];