addRange ( expr, lower, upper, name="" )

Add a range constraint to a model. A range constraint states that the value of the input expression must be between the specified lower and upper bounds in any solution.

Note that range constraints are stored internally as equality constraints. We add an extra variable to the model to capture the range information. Thus, the Sense attribute on a range constraint will always be GRB.EQUAL.


expr: Linear expression for new range constraint. Can be a Var or a LinExpr.

lower: Lower bound for linear expression.

upper: Upper bound for linear expression.


Return value:

New constraint object.

Example usage:

  # 1 <= x + y <= 2
  model.addRange(x + y, 1.0, 2.0, "range0")

  # overloaded forms
  model.addConstr(x + y == [1.0, 2.0], name="range0")