CP-SAT uses a SAT backend. But at any moment, just like with SMT solvers, the full model is never fully represented using clauses and Boolean literals. I recommend looking at the CPAIOR 2020 masterclass on CP (on YouTube) to get a better understanding of the architecture of the solver.
There are different solvers in Excel that are suited for different types of problems:
The Simplex LP solver is the only solver that can guarantee an optimal solution, however, the problem size is somewhat limited and all of the constraints as well as the objective function have to be linear.
Your problem is small, ...
thanks for all your answers. I just wanted to say that the problem was in fact related to the Gurobi license file. I contacted Gurobi and they could reproduce the error and they just gave me a new license. Now everything is okay again.
This does not look like a license issue. This is a Pyomo error code. You should share some more info about the error message and other output before.
If your new license is stored in C:\gurobi\gurobi.lic, Gurobi will find the license automatically and there is usually nothing else required to make it work.
To test the license, it is better to either ...
You need to put the new licence in your terminal and run it
To install this license on a computer where Gurobi Optimizer is installed, copy and paste the following command to the Start/Run menu (Windows only) or a command/terminal prompt (any system like mac):
Let's assume your licence is as follows
For timing within the gurobi solver, maybe you can call <optimizer>.solve() method with report_timing=True, as described in pyomo's documentation at
I haven't used Gurobi before. If gurboipy logs the starting and ending time of the optimization, then you can ...