C++ API - GRBConstr#

class GRBConstr#

Gurobi constraint object. Constraints are always associated with a particular model. You create a constraint object by adding a constraint to a model (using GRBModel::addConstr), rather than by using a GRBConstr constructor.

The methods on constraint objects are used to get and set constraint attributes. For example, constraint right-hand sides can be queried by calling get ( GRB_DoubleAttr_RHS). Note that you can also 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 attribute.

Parameters:

attr – The attribute being queried.

Returns:

The current value of the requested attribute.

double get(GRB_DoubleAttr attr)#

Query the value of a double-valued attribute.

Parameters:

attr – The attribute being queried.

Returns:

The current value of the requested attribute.

int get(GRB_IntAttr attr)#

Query the value of an int-valued attribute.

Parameters:

attr – The attribute being queried.

Returns:

The current value of the requested attribute.

string get(GRB_StringAttr attr)#

Query the value of a string-valued attribute.

Parameters:

attr – The attribute being queried.

Returns:

The current value of the requested attribute.

int index()#

This method returns the current index, or order, of the constraint in the underlying constraint matrix.

Note that the index of a constraint may change after subsequent model modifications.

Returns:

-2: removed, -1: not in model, otherwise: index of the constraint in the model

bool sameAs(GRBConstr constr2)#

Check whether two constraint objects refer to the same constraint.

Parameters:

constr2 – The other constraint.

Returns:

Boolean result indicates whether the two constraint objects refer to the same model constraint.

void set(GRB_CharAttr attr, char newvalue)#

Set the value of a char-valued attribute.

Parameters:

  • attr – The attribute being modified.

  • newvalue – The desired new value of the attribute.

void set(GRB_DoubleAttr attr, double newvalue)#

Set the value of a double-valued attribute.

Parameters:

  • attr – The attribute being modified.

  • newvalue – The desired new value of the attribute.

void set(GRB_IntAttr attr, int newvalue)#

Set the value of an int-valued attribute.

Parameters:

  • attr – The attribute being modified.

  • newvalue – The desired new value of the attribute.

void set(GRB_StringAttr attr, const string &newvalue)#

Set the value of a string-valued attribute.

Parameters:

  • attr – The attribute being modified.

  • newvalue – The desired new value of the attribute.