Run and configure the solver

To run your optimization model call,

m.optimize()

Recall that you chose your solver upon creating your model.

Configure solver parameters

Every solver has a set of parameters that you can read or set using model.params.<your-param>.

GurobiCOPTHiGHSIpopt

Refer to the list of Gurobi parameters.

m = pf.Model("gurobi")
m.params.Method = 2  # Use barrier method
m.params.TimeLimit = 100

Refer to the list of COPT parameters.

m = pf.Model("copt")
m.params.RelGap = 0.01
m.params.TimeLimit = 100

Refer to the list of HiGHS options.

m = pf.Model("highs")
m.params.time_limit = 100.0
m.params.mip_rel_gap = 0.01

Refer to the list of Ipopt options.

m = pf.Model("ipopt")
m.params.tol = 1e-6
m.params.max_iter = 1000

Warning

Ipopt does not support reading parameters (only setting them).

Configure solver attributes

Pyoframe lets you read and set solver attributes using model.attr.<your-attribute>. For example, if you'd like to prevent the solver from printing to the console you can do:

m = pf.Model()
m.attr.Silent = True

Pyoframe supports a set of standard attributes as well as additional Gurobi attributes and COPT attributes.

>>> m.optimize()
>>> m.attr.TerminationStatus  # PyOptInterface attribute (always available)
<TerminationStatusCode.OPTIMAL: 2>
>>> m.attr.Status  # Gurobi attribute (only available with Gurobi)
2

Variable and constraint attributes

Similar to above, Pyoframe allows directly accessing the PyOptInterface or the solver's variable and constraint attributes.

m = pf.Model()
m.X = pf.Variable()
m.X.attr.PrimalStart = 5  # Set initial value for warm start

If the variable or constraint is dimensioned, the attribute can accept/return a DataFrame instead of a constant.

Configure an advanced license

Both COPT and Gurobi support advanced license configurations through the solver_env parameter:

COPTGurobi

# Cluster configuration
m = pf.Model("copt", solver_env={"CLIENT_CLUSTER": "cluster.example.com"})

# Compute server
m = pf.Model(
    "gurobi",
    solver_env={"ComputeServer": "server.example.com", "ServerPassword": "password"},
)

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