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Details of the OPTEX Procedure |

Only the DATA= data set is required. If you do not specify a DATA= data set in the PROC OPTEX statement, the procedure uses the last data set created as a set of candidate points for the design. The AUGMENT= data set iqs optional and contains points that must be included in the final design. The INITDESIGN= data set is also optional and provides an initial design to be used by a search procedure. Variables listed in the MODEL statement must be present in all three of these data sets, and the variable characteristics (type and length) must match across data sets.

Figure 24.2 is a schematic diagram of the roles of the DATA=, AUGMENT=, and INITDESIGN= data sets in constructing the design. Figure 24.3 presents the role of the DESIGN= data set for block designs.

The effects specified in a MODEL statement determine the variables used when generating a design. For example, if the DATA= data set contains the variables A, B, and C, but the MODEL statement specifies effects involving only A and B, then the variable C is not considered when generating designs.

Variables in the DATA= data set that are listed in the ID statement are transferred to the OUT= data set (if one is created).

As with the DATA= data set, the effects specified in a MODEL statement determine the variables used when generating a design. The types and lengths of variables in an AUGMENT= data set that are used in the MODEL and ID statements must match the types and lengths of the same variables in the DATA= data set. If you use an ID statement and the AUGMENT= data set contains the ID variables, these variables are transferred to the OUT= data set (if one is created). See "Including Specific Runs" for an example that uses an AUGMENT= data set.

As with the DATA= data set, the effects specified in a MODEL statement determine the variables used when generating a design. The types and lengths of variables in an INITDESIGN= data set that are used in the MODEL and ID statements must match the types and lengths of the same variables in the DATA= data set. If you use an ID statement and the INITDESIGN= data set contains the ID variables, these variables are transferred to the OUT= data set (if one is created). See Example 24.3 for an example that uses an INITDESIGN= data set.

If you use an INITDESIGN= data set and also specify METHOD=SEQUENTIAL in the GENERATE statement, no search is performed. The INITDESIGN= data set is the final design. In this way, you can use the OPTEX procedure to evaluate an existing design.

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