Configuring the Factors

From the DOE Component WebTop Editor, click the Factors tab.

Determine which parameters you want to define as factors to study by selecting the corresponding check boxes in the first column.

Alternatively, you can click Check All to add all parameters. To clear all the parameters, click Check None.

If you select an array as a factor, a single quantity represents the array in the model and it will be expanded during execution to define a factor for each element in the array. You can override the attributes for each individual element by selecting them separately.

To select aggregates, click and select the scalar members.

Change any of the default values, which are provided for all attributes for a selected factor.

Depending on the technique, a change in one of the columns might automatically update any other columns that are related.

Although each technique defines the appropriate set of attributes for a factor, the following attributes are common among many of the techniques:

• # Levels. The number of levels at which you want to study the factors. A change to this attribute automatically readjusts the levels for this factor.

• Levels. A space-separated list of the levels at which to study the factor. The related attributes are updated once you click in a different cell.

• Lower/Upper. The lower/upper levels for the factor. A change to one of these attributes automatically calculates new levels evenly distributed between the lower and upper values.

• Relation. Specifies whether the levels are interpreted as values or as %/difference (diff) from a specified baseline.

• Baseline. The value used for converting levels into values when the relation is % or diff.

• Values. A space-separated list of the actual values at which to study the factor. The Values are calculated using the Levels (or Lower/Upper values) as a percentage or difference (specified by the Relation attribute) from the Baseline (for techniques that support those attributes). If the list of values is too long to view in the text box in the Values column, click to view the values in a larger window.

  For example, for Levels = “-10 10”, Baseline = 20, Relation = “%”, the Values are calculated as “18.0 22.0”.

  Because the values are calculated from other attributes, you cannot edit the contents of this column.

The following attributes are not common to all the techniques:

• Alpha (Central Composite technique only). The lower and upper levels specify the two levels at which a 2-level full-factorial study is performed. The center point is also studied. The Alpha option is a ratio defining two other points (also known as “star points”) at which to study the given factor. For example, Alpha set to 0.25 indicates the factor is to be studied at points 1/4 of the way from the baseline to the lower and upper levels. Alpha set to 1.5 indicates the factor is to be studied 50% beyond the lower and upper levels. For example, Lower = 5, Upper = 20, Baseline = 10, and Alpha = 0.25 results in Levels = {5, 8.75, 10, 12.5, 20}.

• Column (Data File only). If you specified to not use a header row to find factors in the file, you must provide the column number for each factor.

Click Update factor baselines to current values when executing if you want the baseline values updated to the current parameter values before executing.

If Isight previously modified a parameter, this option allows for automatic updating of the baseline of all factors to the current parameter values in Isight, prior to executing the DOE technique, which will readjust the values to be studied appropriately. By default, this option is not selected and the user-defined settings are retained. This option is useful if the DOE technique is executed after another element of the simulation process flow that might change the parameter values (e.g., after an Optimization component), so that the DOE study can be performed around the new design point.

Click Update Component to save your changes.