Known issues in Gurobi 13.0

Known issues in Gurobi 13.0.0

Incorrect names and dictionary keys generated by addConstrs

With Python 3.13, Model.addConstrs incorrectly determines the indices to be used for generated constraint names when iterating over a predefined list of tuples.

keys = [(0, 1), (1, 0), (1, 1)]
model.addConstrs(
    (<expression> for i, j in keys),
    name="C",
)
# Expected names: C[0,1] C[1,0] C[1,1]
#   Actual names: C[]    C[]    C[]

If you encounter any unexpected behaviour from addConstrs we recommend adjusting your code to use Model.addConstr instead, the equivalent code being:

keys = [(0, 1), (1, 0), (1, 1)]
for i, j in keys:
    model.addConstr(
        <expression>,
        name=f"C[{i},{j}]",
    )