Quanmeng Wang

Thanks very much, I solved the problem by re-activating the license.   I did not know that the activation of gurobi should be done for each different user of a school PC.       

Hi, actually I did not even declare a GRBModel. Below is the screenshot      It is simple, so I suspect it should be the problem of configuration of Gurobi.

Thanks a lot! Now on some small instances my code works.   Just one quick question.. When the following code is excuted, model = new GRBModel(env); Every time the system allocate some new location ...