Job Shop Scheduling

[Viktor Pot]

I am writing a Job shop scheduling program. That is scalable to a Flexible job shop scheduling program.

I use the Gurobi interface in python (in spyder IDE).

I attached the .py file. I did not need to explicitly put the Job ID in my variables since I obtain the Operation ID from the dictionary O[i] (which gives the required operations for a job). Normally, my data should be fine. I used pandas to read in csv files.

My main problem lies in the sequencing constraints, where I use 'sigma' do denote a sequence. I mostly follow a mathematical formulation from the literature. Also using the bigM formulation. When i used GRB.INFINITY as a value for bigM, the model was feasible but the sequencing was not done properly. And now I assigned the value 1e10 to bigM, and the model is infeasible.

Does anyone have some tips, or has had similar problems? Also if someone has a proper Job Shop Scheduling example code, it would be really helpful.

Thank you in advance,

Viktor (university student)