GRBQConstr#

GRBQConstr#

Gurobi quadratic constraint object. Quadratic constraints are always associated with a particular model. You create a quadratic constraint object by adding a quadratic constraint to a model (using GRBModel.addQConstr), rather than by using a GRBQConstr constructor.

The methods on quadratic constraint objects are used to get and set constraint attributes. For example, quadratic constraint right-hand sides can be queried by calling get (GRB.DoubleAttr.QCRHS). Note, however, that it is generally more efficient to query attributes for a set of constraints at once. This is done using the attribute query method on the GRBModel object (GRBModel.get).

char get(GRB.CharAttr attr)#

Query the value of a char-valued quadratic constraint attribute.

Arguments:

attr – The attribute being queried.

Return value:

The current value of the requested attribute.

Example:
// Get constraint sense
char sense = constr.get(GRB.CharAttr.QCSense);
double get(GRB.DoubleAttr attr)#

Query the value of a double-valued quadratic constraint attribute.

Arguments:

attr – The attribute being queried.

Return value:

The current value of the requested attribute.

Example:
// Get RHS
double rhs = constr.get(GRB.DoubleAttr.QCRHS);
int get(GRB.IntAttr attr)#

Query the value of an int-valued quadratic constraint attribute.

Arguments:

attr – The attribute being queried.

Return value:

The current value of the requested attribute.

Example:
// Get information whether constraint participates in a previously computed IIS
int iisqconstr = constr.get(GRB.IntAttr.IISQConstr);
String get(GRB.StringAttr attr)#

Query the value of a string-valued quadratic constraint attribute.

Arguments:

attr – The attribute being queried.

Return value:

The current value of the requested attribute.

Example:
// Get constraint name
String name = constr.get(GRB.StringAttr.QCName);
void set(GRB.CharAttr attr, char newval)#

Set the value of a char-valued quadratic constraint attribute.

Arguments:

  • attr – The attribute being modified.

  • newval – The desired new value of the attribute.

Example:
// Set constraint sense
constr.set(GRB.CharAttr.QCSense, '>');
void set(GRB.DoubleAttr attr, double newval)#

Set the value of a double-valued quadratic constraint attribute.

Arguments:

  • attr – The attribute being modified.

  • newval – The desired new value of the attribute.

Example:
// Set RHS
constr.set(GRB.DoubleAttr.QCRHS, 2.0);
void set(GRB.IntAttr attr, int newval)#

Set the value of an int-valued quadratic constraint attribute.

Arguments:

  • attr – The attribute being modified.

  • newval – The desired new value of the attribute.

Example:
// Force constraint into IIS
constr.set(GRB.IntAttr.IISQConstrForce, 1);
void set(GRB.StringAttr attr, String newval)#

Set the value of a string-valued quadratic constraint attribute.

Arguments:

  • attr – The attribute being modified.

  • newval – The desired new value of the attribute.

Example:
// Set constraint name
constr.set(GRB.StringAttr.QCName, "newName");