Simranjit Kaur

Thanks, Enprimarika. It is a good step to name the constraints. However, without knowing the coefficients and the RHS of the constraints in the IIS, it is hard to tell what is leading to the infeas...

You can obtain additional information about the constraints R769 and R823 in the IIS by exporting an .ilp format file using  model.write("conflict.ilp")  

Hi, The model.write() call implicitly updates the model and processes all pending model modifications. In your example, when you add the lazy constraints using model.addConstr() and write the lp fi...

Hi Purnima, I don't see any errors in your code. The KeyError is raised because you are attempting to access a key that is not present in a dictionary. Please crosscheck that the data is read from ...

Hi, To use the gurobi_ml module, please ensure that you have installed the gurobi-machinelearning package. The package can be installed easily via pip: pip install gurobi-machinelearning For more ...

Hi, Unfortunately, it is not possible to write lazy constraints or user cuts added via callback with Model.write() function directly. However, you can workaround this by tracking the lazy constrain...

Hi Qiru, Please introduce an auxiliary variable y, and replace the constraint MODEL.addConstr(b[2]*e1 + b[4]*e2 + b[7]*e3 == gb.max_([b[k] for k in range(0, 8)]) ) with the following y = MODEL.addV...

Hi Qiru, The error “gurobipy.GurobiError: Variable has not yet been added to the model” happens due to Gurobi’s lazy update approach, precisely when we try to access and use a variable before updat...

Hi, The behaviour you are observing occurs mostly when a model has numerical issues. Numerical issues can sometimes result in the simplex algorithm declaring the model infeasible while the IIS cons...

Hi Ramesh, To ensure that D is zero when the binary variable C is zero, you can add another indicator constraint:  m.addConstr( (C==0) >> (D==0) ) Alternatively, you can add a Big-M constraint, m.a...