at first, congratulations for the great development of Glpk (I got started with 4.13 version). In spite of the not very related subject, my question is, does somebody knows a "free solver" to solve a non-linear constrained problem or some method to linearize the product between integer and binary variables?. My model has one variable in the objective function and a set of constraints with: one non-linear constraint (product mentioned above) and some others mixed integer linear constraints. Thanks in advance.