GRBGenConstr#

GRBGenConstr#

Gurobi general constraint object. General constraints are always associated with a particular model. You create a general constraint object by adding a general constraint to a model (using one of the GRBModel.addGenConstr* methods), rather than by using a GRBGenConstr constructor.

The methods on general constraint objects are used to get and set constraint attributes. For example, general constraint types can be queried by calling get (GRB.IntAttr.GenConstrType). 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).

The full list of attributes can be found in the Attributes section of this document. Examples of how to query and set attributes can also be found in this section.

double get(GRB.DoubleAttr attr)#
int get(GRB.IntAttr attr)#
String get(GRB.StringAttr attr)#

Query the value of a general constraint attribute.

Arguments:

attr – The attribute being queried.

Return value:

The current value of the requested attribute.

Example:
// Get PWL approximation error
double funcpieceerror = gc.get(GRB.DoubleAttr.FuncPieceError);
// Get general constraint type
int type = gc.get(GRB.IntAttr.GenConstrType);
// Get general constraint name
String name = gc.get(GRB.StringAttr.GenConstrName);
void set(GRB.DoubleAttr attr, double newval)#
void set(GRB.IntAttr attr, int newval)#
void set(GRB.StringAttr attr, String newval)#

Set the value of a general constraint attribute.

Arguments:

  • attr – The attribute being modified.

  • newval – The desired new value of the attribute.

Example:
// Set PWL approximation error
gc.set(GRB.DoubleAttr.FuncPieceError, 1e-4);
// Set number of PWL pieces
gc.set(GRB.IntAttr.FuncPieces, 100);
// Set name of general constraint
gc.set(GRB.StringAttr.GenConstrName, "newName");