HEADNODE Statement

HEADNODE variable ;

HEAD variable ;

TONODE variable ;

TO variable ;

The HEADNODE statement specifies the SAS variable that must be present in the ARCDATA= data set that contains the names of nodes toward which arcs are directed. It is not necessary to have a HEADNODE statement if the name of the SAS variable is _HEAD_ or _TO_. The HEADNODE variable must have character values.

There should be no HEAD statement if you are solving an LP.