Scripting Guide - SAS

Chapter 10 Scripting Platforms 327
Additional Notes
Tuning Commands
Starts, Sphere Radius, Disallowed Combinations, Advanced Options (Search
Points Per Factor, Mixture Sum, Split Plot Variance Ratio, Number of Monte
Carlo Samples, N Monte Carlo Spheres), Add Response, Add Factor, Add Term,
Add Potential Term, Add Constraint, Make Model, Make Design, Make Table, Set
Sample Size, Set N Whole Plots, Set N Subplots, Set Runs Per Random Block,
Make Strip Plot Design, Center Points, Replicates, Report, Prior Parameter
Variance, Theta(a vector that applies to only Maximum Entropy and IMSE
designs, Entropy, Sphere Packing, Latin Hypercube, Uniform, Minimum
Potential, IMSE
There are scripting commands that let you predefine guidelines for the design search by the custom
designer. The following commands are described briefly here, and examples also appear in the Design of
Experiments.
DOE Mixture Sum If you want to keep a component of a mixture constant throughout an experiment
then the sum of the other mixture components must be less than one. In defining the factors, you enter
the constant mixture component as a constant factor. For example, if you have a mixture factor with a
constant value of 0.1, then the command
DOE Mixture Sum = 0.9;
constrains the remaining mixtures factors to sum to 0.9 instead of the default 1.0.
DOE Starts is the number of random starts used by the custom designer. In some situations, the default
number of starts might not produce the design that you want. You can increase the number of starts
with the DOE Starts command. For example, submitting the JSL statement
DOE Starts = 100;
overrides the default number of starts and sets the number of starts to 100.
DOE Starting Design For example,
DOE Starting Design = matrix;
replaces the random starting design with a specified matrix. If a starting design is supplied, the custom
designer has only one start using this design.
DOE Search Points Per Factor For a linear model, the coordinate exchange algorithm in the custom
designer only considers the high and low values by default. Suppose the low and high values for a factor
are -1 and 1 respectively. If you submit the JSL command:
DOE Search Points Per Factor = 11;
then for each row, the coordinate exchange algorithm checks the eleven values, –1, -0.8, –0.6, –0.4,
–0.2, 0, 0.2, 0.4, 0.6, 0.8, 1.0.
DOE K Exchange Value By default, the coordinate exchange algorithm considers every row of factor
settings for possible replacement in every iteration. Some of these rows might never change. For example
DOE K Exchange Value = 3;
sets this value to a lower number, three in this case, so the algorithm only considers the most likely three
rows for exchange in each iteration.