I'm getting the following error, while trying to set up IntegralityFocus for Gurobi backend in Sage 9.2:
sage: from sage_numerical_backends_gurobi.gurobi_backend import GurobiBackend as mysolver
sage: milp = MixedIntegerLinearProgram(solver=mysolver)
sage: milp.solver_parameter("IntegralityFocus", 1)
---------------------------------------------------------------------------
KeyError Traceback (most recent call last)
sage_numerical_backends_gurobi/gurobi_backend.pyx in sage_numerical_backends_gurobi.gurobi_backend.GurobiBackend.solver_parameter()
KeyError: 'IntegralityFocus'
During handling of the above exception, another exception occurred:
ValueError Traceback (most recent call last)
<ipython-input-3-65373ae60dc1> in <module>
----> 1 milp.solver_parameter("IntegralityFocus", Integer(1))
/usr/local/SageMath.92/local/lib/python3.8/site-packages/sage/numerical/mip.pyx in sage.numerical.mip.MixedIntegerLinearProgram.solver_parameter (build/cythonized/sage/numerical/mip.c:16597)()
2470 return self._backend.solver_parameter(name)
2471 else:
-> 2472 self._backend.solver_parameter(name, value)
2473
2474 cpdef sum(self, L):
sage_numerical_backends_gurobi/gurobi_backend.pyx in sage_numerical_backends_gurobi.gurobi_backend.GurobiBackend.solver_parameter()
ValueError: This parameter is not available. Enabling it may not be so hard, though.
Ok, it says "Enabling it may not be so hard, though." but HOW?
