C++ API - GRBVar#

class GRBVar#

Gurobi variable object. Variables are always associated with a particular model. You create a variable object by adding a variable to a model (using GRBModel::addVar), rather than by using a GRBVar constructor.

The methods on variable objects are used to get and set variable attributes. For example, solution information can be queried by calling get ( GRB_DoubleAttr_X). Note that you can also query attributes for a set of variables 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 variable in the underlying constraint matrix.

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

Returns:

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

bool sameAs(GRBVar var2)#

Check whether two variable objects refer to the same variable.

Parameters:

var2 – The other variable.

Returns:

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

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.