GRBVar#
- 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 aGRBVar
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, however, that it is generally more efficient to query attributes for a set of variables at once. This is done using the attribute query method on theGRBModel
object (GRBModel.Get
).- Example:
// Add continuous variable in [0,1] called "var" to model GRBVar var = model.AddVar(0.0, 1.0, 0.0, GRB.CONTINUOUS, "var");
' Add continuous variable in [0,1] called "var" to model Dim var As GRBVar = model.AddVar(0.0, 1.0, 0.0, GRB.CONTINUOUS, "var")
- 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.
- Example:
// Get VType value char vtype = var.Get(GRB.CharAttr.VType);
' Get VType value Dim vtype As Char = var.Get(GRB.CharAttr.VType)
- 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.
- Example:
// Get lower bound value double lb = var.Get(GRB.DoubleAttr.LB);
' Get lower bound value Dim lb As Double = var.Get(GRB.DoubleAttr.LB)
- 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.
- Example:
// Get VBasis value int vbasis = var.Get(GRB.IntAttr.VBasis);
' Get VBasis value Dim vbasis As Integer = var.Get(GRB.IntAttr.VBasis)
- 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.
- Example:
// Get variable name string name = var.Get(GRB.StringAttr.VarName);
' Get variable name Dim name As String = var.Get(GRB.StringAttr.VarName)
- int Index#
This property 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
- Example:
int index = var.Index;
Dim index As Integer = var.Index
- 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.
- Example:
// Compare to a second variable bool issame = var.SameAs(var2);
' Compare to a second variable Dim issame As Boolean = var.SameAs(var2)
- 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.
- Example:
// Set VType value var.Set(GRB.CharAttr.VType, GRB.BINARY);
' Set VType value var.Set(GRB.CharAttr.VType, GRB.BINARY)
- 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.
- Example:
// Set lower bound value var.Set(GRB.DoubleAttr.LB, 0.1);
' Set lower bound value var.Set(GRB.DoubleAttr.LB, 0.1)
- 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.
- Example:
// Set VBasis value var.Set(GRB.IntAttr.VBasis, -1);
' Set VBasis value var.Set(GRB.IntAttr.VBasis, -1)
- void Set(GRB.StringAttr attr, string newvalue)#
Set the value of a string-valued attribute.
- Parameters:
attr – The attribute being modified.
newvalue – The desired new value of the attribute.
- Example:
// Set variable name var.Set(GRB.StringAttr.VarName, "newName");
' Set variable name var.Set(GRB.StringAttr.VarName, "newName")