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MQConstr
Gurobi matrix quadratic constraint object. An MQConstr object is an
array-like data structure that represents multiple quadratic constraints (in
contrast to a QConstr object, which
represents a single quadratic constraint). It behaves similar to NumPy's
ndarrays, e.g., it has a shape and can be indexed and sliced. Matrix
quadratic constraints are always associated with a particular model. You
typically create these objects with
Model.addConstr, using overloaded
comparison operators on matrix variables,
matrix linear expressions, and
matrix quadratic expressions.
Quadratic constraint objects have a number of attributes. The full list can be found in the Attributes section of this document. Some constraint attributes can only be queried, while others can also be set. Recall that the Gurobi optimizer employs a lazy update approach, so changes to attributes don't take effect until the next call to Model.update, Model.optimize, or Model.write on the associated model.
We should point out a few things about quadratic constraint attributes.
Consider the QCRHS attribute. The values for a matrix quadratic
constraint mqc can be queried using mc.QCRHS. The Gurobi library
ignores letter case in attribute names, so it can also be queried as
mc.qcrhs. Attribute values are returned as a NumPy ndarray that
has the same shape as qmc. An attribute can be set, using a standard
assignment statement (e.g., mqc.qcrhs = b), with b being either
an ndarray with the appropriate shape, or a scalar which is then applied
to all of the associated quadratic constraints. However, as mentioned earlier,
attribute modification is done in a lazy fashion, so you won't see the effect
of the change immediately. And some attributes can not be set (e.g., the
QCPi attribute), so attempts to assign new values to them will raise an
exception.
You can also use MQConstr.getAttr/
MQConstr.setAttr to access
attributes. The attribute name can be passed to these routines as a
string, or you can use the constants defined in the
GRB.Attr class (e.g.,
GRB.Attr.QCRHS).
Subsections
