Configuring the Downhill Simplex Technique

You can configure the Downhill Simplex technique options.

  1. Double-click the Optimization icon .
    The Optimization Component Editor appears.
  2. From the General tab's Optimization Technique list, select DownhillSimplex.

  3. In the Optimization Technique Options area, enter the following:
    OptionDescription
    Initial Simplex Size This is the size of the starting simplex as a fraction of your domain. It must be a real value greater than zero and less than or equal to one. It has the highest probability of finding a global optimum when started with a bigger initial size. Because it spans a larger fraction of the design space, the chances of getting trapped in a local minimum are smaller. The default value is 0.1, which is equivalent to 10% of the domain.
    Maximum Iterations This parameter defines the number of times a simplex would execute a reflection (and, in addition, the potential expansion or contraction) in search of the optimum design. The value type is integer. The default value is 40. Note that, this setting does not directly define the absolute number of subflow evaluations.
    Simplex Count Extends the standard Downhill Simplex process by allowing a design search to be performed with more than one simplex running in parallel. When you select Execute in parallel to enable parallel processing and N simplexes are active, the SIMULIA Execution Engine dispatches a batch of N points, one per simplex, on each iteration.
    Maximum Failed Runs This parameter is used to set the maximum number of failed subflow evaluations that can be tolerated by the optimization technique. If the number of failed runs exceeds this value, the optimization component will terminate execution. To disable this feature, set this option to any negative value (for example, –1). When this option is set to a negative value, the optimization will continue execution despite any number of failed subflow runs.
    Failed Run Penalty Value This parameter represents the value of the Penalty parameter that is used for all failed subflow runs. The default value is 1×1030.
    Failed Run Objective Value This parameter represents the value of the Objective parameter that is used for all failed subflow runs. The default value is 1×1030.
  4. Click OK to save your changes and to close the Optimization Component Editor.