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 a GRBSOS constructor. Similarly, SOS constraints are removed using the GRBModel.remove method.

An SOS constraint can be of type 1 or 2 (GRB.SOS_TYPE1 or GRB.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 a number of attributes, e.g., IISSOS, which can be queried with the GRBSOS.get method.

The full list of attributes can be found in the Attributes section of this document. Examples of how to query and set attributes can also be found in this section.

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.

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.