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.

General constraint objects have a number of attributes, which can be queried with the GRBGenConstr.Get method. The full list can be found in the Attributes section of this document.

Example:
// Create binary indicator variable
GRBVar z = model.AddVar(0.0, 1.0, 0.0, GRB.BINARY, "resvar");
// Create variables
GRBVar x = model.AddVar(0.0, GRB.INFINITY, 0.0, GRB.CONTINUOUS, "x");
GRBVar y = model.AddVar(0.0, GRB.INFINITY, 0.0, GRB.CONTINUOUS, "y");
// Add constraint if resvar = 1 then x + y <= 2
GRBGenConstr gc = model.AddGenConstrIndicator(z, 1, x + y <= 2.0, "indicatorconstr");
double Get(GRB.DoubleAttr attr)#

Query the value of a double-valued general constraint attribute.

Parameters:

attr – The attribute being queried.

Returns:

The current value of the requested attribute.

Example:
// Get PWL approximation error
double funcPieceError = gc.Get(GRB.DoubleAttr.FuncPieceError);
int Get(GRB.IntAttr attr)#

Query the value of an int-valued general constraint attribute.

Parameters:

attr – The attribute being queried.

Returns:

The current value of the requested attribute.

Example:
// Get general constraint type
int type = gc.Get(GRB.IntAttr.GenConstrType);
string Get(GRB.StringAttr attr)#

Query the value of a string-valued general constraint attribute.

Parameters:

attr – The attribute being queried.

Returns:

The current value of the requested attribute.

Example:
// Get general constraint name
string name = gc.Get(GRB.StringAttr.GenConstrName);
void Set(GRB.DoubleAttr attr, string newvalue)#

Set the value of a double-valued general constraint attribute.

Parameters:

  • attr – The attribute being modified.

  • newvalue – The desired new value of the attribute.

Example:
// Set PWL approximation error
gc.Set(GRB.DoubleAttr.FuncPieceError, 1e-4);
void Set(GRB.IntAttr attr, string newvalue)#

Set the value of an int-valued general constraint attribute.

Parameters:

  • attr – The attribute being modified.

  • newvalue – The desired new value of the attribute.

Example:
// Set number of PWL pieces
gc.Set(GRB.IntAttr.FuncPieces, 100);
void Set(GRB.StringAttr attr, string newvalue)#

Set the value of a string-valued general constraint attribute.

Parameters:

  • attr – The attribute being modified.

  • newvalue – The desired new value of the attribute.

Example:
// Set name of general constraint
gc.Set(GRB.StringAttr.GenConstrName, "newName");