GRBSOS#
- GRBSOS#
Gurobi SOS constraint object. SOS constraints are always associated with a particular model. You create an SOS object by adding an SOS constraint to a model (using
GRBModel.addSOS
), rather than by using aGRBSOS
constructor. Similarly, SOS constraints are removed using theGRBModel.remove
method.An SOS constraint can be of type 1 or 2 (
GRB.SOS_TYPE1
orGRB.SOS_TYPE2
). A type 1 SOS constraint is a set of variables where at most one variable in the set may take a value other than zero. A type 2 SOS constraint is an ordered set of variables where at most two variables in the set may take non-zero values. If two take non-zero values, they must be contiguous in the ordered set.SOS constraint objects have one attribute, IISSOS, which can be queried with the
GRBSOS.get
method.- Example:
// 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"); // Create helper arrays GRBVar[] vars = {x, y}; double[] weights = {1.0, 2.0}; // Add SOS1 constraint over x and y GRBSOS constr = model.addSOS(vars, weights, GRB.SOS_TYPE1);
- int get(GRB.IntAttr attr)#
Query the value of an SOS attribute.
- Arguments:
attr – The attribute being queried.
- Return value:
The current value of the requested attribute.
- Example:
// Get information whether constraint participates in a // previously computed IIS int iissos = constr.get(GRB.IntAttr.IISSOS);
- void set(GRB.IntAttr attr, int newval)#
Set the value of an SOS attribute.
- Arguments:
attr – The attribute being modified.
newval – The desired new value of the attribute.
- Example:
// Force constraint into IIS constr.set(GRB.IntAttr.IISSOSForce, 1);