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Decision variable

ClientDecisionVariable

Bases: Variable

Client (follower) decision variable for bilevel hub location.

Binary variable that captures whether client \(z\) on route \((i,j)\) accepts the price offered by the leader:

\[y_{ij}^z \in \{0,1\} \quad \forall i,j \in V, z \in M_{ij}\]

The client accepts if and only if their utility is non-negative: \(a_{ij}^z p_{ij} - b_{ij}^z \geq 0\).

The variable is indexed by (i, j, z): origin \(i\), destination \(j\), and client index \(z\) on that route.

build(model)

Create binary Gurobi variables over all client routes.

Source code in src/oracle_paper/variables/decision_variable.py 
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def build(self, model: "BaseModel") -> tupledict:
    """Create binary Gurobi variables over all client routes."""
    client_keys = model.data[BilevelDataCol.CLIENT_ID_ROUTE]
    return model.model.addVars(
        client_keys,
        vtype=GRB.BINARY,
        name=str(self.var_metadata),
    )