I've posted the notes for Lecture 3 and the GMPL file for the Network/Transportation example we developed in class. I polished up the class example with comments, attributions, cleaned up variable names and so forth so that it is a good example of GMPL programming practice. Be sure to understand and master the basic techniques demonstrated in this example.
Assignment 2 is due Friday, and Assignment 3 -- the "Custom Vans, Inc." case study will be due next Tuesday. Assignments 4 and 5 can wait until after the Thanksgiving holiday. We're moving pretty rapidly, so we're trying to maintain an appropriate balance between workload and staying current with lecture topics.
Finally, I've added some additional GMPL examples for Lecture 2. These are mainly demonstrations of techniques in GMPL including some rather exotic computations one can do with sets. You may find these useful if you find yourself trying to do complicated manipulations with sets.
For what it's worth, I'm finding the Greenhouse to be a good room for teaching. Unless there are objections, let's try to meet there for upcoming class sessions.