The CLP Procedure

The CLP procedure is a finite-domain constraint programming solver for solving constraint satisfaction problems (CSPs) with linear, logical, global, and scheduling constraints. The CLP procedure is production in SAS/OR 9.22 with the exception of the scheduling-related constraints.

New in SAS/OR 9.22 are the GCC and ELEMENT statements for defining global cardinality constraints (GCC) and element constraints, respectively. The GCC statement enables you to bound the number of times that a specific value gets assigned to a set of variables. The ELEMENT statement enables you to define dependencies, not necessarily functional, between variables and to define noncontiguous domains.

The USECONDATAVARS= option enables you to implicitly define numeric variables in the CONDATA= data set. The TIMETYPE= option enables you to set the units (real time or CPU time) of the MAXTIME= parameter. The _ORCLP_ macro variable has been enhanced to provide more information about procedure status and solution status.

There are also several changes and enhancements to the scheduling capabilities in SAS/OR 9.22. Support for multiple-capacity resources has been added in the RESOURCE statement and the Activity data set. The REQUIRES statement syntax for specifying multiple resource requirements has changed. The format of the Activity data set has changed to a more compact form with a fixed number of variables. A new Resource data set, specified with the RESDATA= option, enables you to define resources, resource pools, and resource attributes in compact form. The format of the Schedule data set has been enhanced to separate time and schedule related observations. Two new schedule-related output data sets, SCHEDTIME= and SCHEDRES=, have been added; they contain time assignment and resource assignment information, respectively.