DOCUMENTATION
Sign In

Get access to My SAS, trials, communities and more.

Mathematical Optimization Procedures
 

The MPS-Format Data Table

SOS Section (Optional)

A special ordered set (SOS) defines restrictions on the integer variables in the set. An SOS of type 1 is an ordered set of variables in which only one variable can be nonzero. The order of the weights of the variables defines the order of the variables. If you do not specify the weights, then the default weights are assigned to the variables in the order in which they appear.

In the SOS section, you can describe multiple SOSs. The description of an SOS begins with a set declaration record, which is followed by multiple member declaration records. The set declaration record specifies the SOS type (S1) and the name of this SOS. The member declaration records specify the variables and their corresponding weights. The format is as follows:

  • Indicator record:

    _ID_ Field1 Field2 Field3 Field4 Field5 Field6
    Number SOS Blank Blank . Blank .

  • Set declaration record:

    _ID_ Field1 Field2 Field3 Field4 Field5 Field6
    Number SOS type SOS name (optional) Blank . Blank .

  • Member declaration record:

    _ID_ Field1 Field2 Field3 Field4 Field5 Field6
    Number Blank SOS variable name Blank SOS variable weight Blank .

Notes:

  1. The variable field1 of a set declaration record indicates the SOS type, which must be S1.

  2. You must specify a weight for either all members of an SOS or none of the members. In the latter case, the weights are assigned to the member variables.

Last updated: June 22, 2026