This function sets a choice point and then ranks the resource constraint rct to be first on its resource. In case of failure, rct is set to be not first on its resource. If the resource is not closed, then ranking rct to be not first has no influence on the earliest start time of the activity of rct.

Ranking facilities are defined only for unary and state resources whose ranking information is available (see IlcResource::hasRankInfo). A resource constraint can be ranked if and only if its time extent is IlcFromStartToEnd.

For more information, see Ranking .