GRBVar#

GRBVar#

Gurobi variable object. Variables are always associated with aparticular model. You create a variable object by adding a variable to amodel (usingGRBModel.AddVar), rather than by using aGRBVar constructor.

Example:

C#Visual Basic

// Add continuous variable in [0,1] called "var" to modelGRBVarvar=model.AddVar(0.0,1.0,0.0,GRB.CONTINUOUS,"var");

The methods on variable objects are used to get and set variableattributes. For example, solution information can be queried by callingGet (GRB.DoubleAttr.X).It can also be queried more directly usingvar.RHS wherevaris a GRBVar object. Note, however,that it is generally more efficient to query attributes for a set ofvariables at once. This is done using the attribute query method on theGRBModel object (GRBModel.Get).

The full list of attributescan be found in theAttributes section of thisdocument. Examples of how to query and set attributes can also be foundinthis section.

charGet(GRB.CharAttrattr)#

doubleGet(GRB.DoubleAttrattr)#

intGet(GRB.IntAttrattr)#

stringGet(GRB.StringAttrattr)#

Query the value of an attribute.

Parameters:

attr – The attribute being queried.

Returns:

The current value of the requested attribute.

Example:

C#Visual Basic

// Get VType valuecharvtype=var.Get(GRB.CharAttr.VType);// Get lower bound valuedoublelb=var.Get(GRB.DoubleAttr.LB);// Get VBasis valueintvbasis=var.Get(GRB.IntAttr.VBasis);// Get variable namestringname=var.Get(GRB.StringAttr.VarName);

intIndex#

This property returns the current index, or order, of the variable in theunderlying constraint matrix.

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

Returns:

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

Example:

C#Visual Basic

intindex=var.Index;

boolSameAs(GRBVarvar2)#

Check whether two variable objects refer to the same variable.

Parameters:

var2 – The other variable.

Returns:

Boolean result indicates whether the two variable objects referto the same model variable.

Example:

C#Visual Basic

// Compare to a second variableboolissame=var.SameAs(var2);

voidSet(GRB.CharAttrattr,charnewvalue)#

voidSet(GRB.DoubleAttrattr,doublenewvalue)#

voidSet(GRB.IntAttrattr,intnewvalue)#

voidSet(GRB.StringAttrattr,stringnewvalue)#

Set the value of an attribute.

Parameters:

• attr – The attribute being modified.

• newvalue – The desired new value of the attribute.

Example:

C#Visual Basic

// Set VType valuevar.Set(GRB.CharAttr.VType,GRB.BINARY);// Set lower bound valuevar.Set(GRB.DoubleAttr.LB,0.1);// Set VBasis valuevar.Set(GRB.IntAttr.VBasis,-1);// Set variable namevar.Set(GRB.StringAttr.VarName,"newName");