Configuring the Sobol Sequence Technique

You can configure the Sobol Sequence technique options.

  1. Double-click the DOE component .
    The DOE Component Editor appears.
  2. From the DOE Technique list on the General tab, select Sobol Sequence.
  3. In the DOE Technique Options area, enter the Number of Points that you want to study. For each point, the Sobol Sequence point (a number on the unit interval) is applied to the design space for each factor.
  4. Enter the Skip Runs value to control the starting value from the Sobol Sequence to be used for the design points.

    The default value of 0 indicates that no initial values in the Sobol Sequence are skipped.

  5. Click on Factors tab, select desired parameters.
    Click on Constraint... if you wish to apply constraint on factors. This opens a Constraint Expression dialogue box where you can specify the constraint expression you wish to impose on factors.
    Note:
    • The expression must be a Boolean expression i.e. the evaluated expression must always return a Boolean value.
    • The dialogue box will not close unless it has valid expression which evaluates to a Boolean value
    • Since the constraint is to be defined by an end user, it may happen that the defined constraint is too restrictive, or even impossible to be fulfilled. In such a scenario, the search for valid design points may go on for too long duration, or may not end at all. To avoid the possibility of too long or indefinite search for valid points, a timeout field Max time to find compliant points (seconds): is added in the dialogue with default value as 60 seconds. The timeout must be a non-zero and positive integer value.
    • If timeout is reached before expected number of points are generated, the technique will stop searching for new points and return all the valid points generated till the timeout expires.
    • The filter option available on Design Matrix tab is no more available for Sobol Sequence technique. If a filter expression has been defined for Sobol Sequence technique in models authored using Isight 2021, the filter expression shall be ignored when such model is executed using Isight 2023 or later.
  6. Click OK to save your changes and to close the DOE Component Editor.