Configuring the Execution Options

You can use the General tab to configure general and advanced execution options that you want Isight to take during execution.

  1. Double-click the SDI component icon .

    The SDI Component Editor appears.

  2. From the SDI Component Editor, click the General tab.

  3. In the Execution Options area, select the execution mode. The following options are available:

    Option Description
    Improve Design This mode implements the SDI algorithm to move the current design closer to the desired response targets. Improve Design is the default mode.
    1. Click Number of SDI Steps to specify the number of new designs chosen and the number of new sample sets executed. Each step produces a new “best” design point unless no improvement (no points closer to the target) greater than the Termination Threshold Distance is identified. The default is 5 steps.
    2. Click Number of Samples per Step to specify the number of Monte Carlo samples that are performed at each SDI iteration. The samples are taken across the distributions of the random variables and the local range of the design variables. A large sample set is not necessary because the goal is to find a design closer to the targets, not to calculate response statistics. The default is 16 samples.
    3. Click Termination Threshold Distance to specify the percent change in the distance below which the SDI process will terminate early (before all steps executed). The default is 10%.

      If the difference between the previous distance to the target and the new closest distance to the target is not more than 10% of the previous distance, the SDI process terminates. In this case, the change in distance and associated change in performance cannot be distinguished from the noise associated with uncontrollable, uncertain random variables. You must use caution when reducing the value of this option.
    Analyze Design This mode performs a Monte Carlo simulation around the current design point (current parameter values), varying only random variables.
    1. Click Number of Simulations to determine the number of simulations that are executed. In general, a higher number of simulations results in an increase in the accuracy level of statistical predictions. The default number is 100.

      Note: If you select Analyze Design, you do not have to configure any design variables.
    Execute sample points in parallel Select this option if you want the sample points for each SDI step or the complete sample set in Analyze Design mode to execute in parallel.

    Note: The number of CPUs available may limit the number of sample points that are actually executed in parallel.
    Use a fixed seed Select this option to manually specify the seed in the corresponding text box. If this option is not selected, Isight determines the seed randomly.

    Note: A fixed seed can also be set and used for the entire model. If a fixed seed is set for the model and also defined separately in the SDI component, Isight uses the one defined in the SDI component. If a fixed seed is set for the model and this option is not selected, the sequence of random numbers is based on the model’s random seed (and, thus, is still reproducible). For information about setting a fixed seed, see the Isight User’s Guide.

  4. If desired, map the values of these settings (with the exception of Use a fixed seed) to a parameter.

    For more information, see Mapping Options and Attributes to Parameters.

  5. If desired, click Advanced Options, and set the following:

    1. Click Execute subflow only once to execute the subflow only one time. This is useful in models that need to turn the driver logic on/off parametrically. This option is also helpful in the debugging process if the model does not execute successfully.

      You can map this setting to a parameter. For more information, see Mapping Options and Attributes to Parameters.

    2. Click Allow the following items to be turned off by parameters to de-activate (turn off) the selected types of design parameters (design variables, random variables, responses) using input parameters to the SDI component. If this option is selected, Boolean input parameters are created in an Active Design Variables/Active Random Variables/Active Responses aggregate under the Mapped Options and Attributes aggregate parameter. The parameters are selected by default. Parameters that are not selected at run time are not used during execution.
    3. Click Import configuration at runtime to import the SDI component configuration from a file at run time. If selected, Isight creates an input file parameter on the SDI component called Configuration. You can point the configuration file to a specific file or map it from a file parameter from a previous component in the simulation process flow. Click the button to configure the file parameter to point to the desired file. You can also configure this file on the Design Gateway Files tab. For information about importing/exporting and the file format, see About Importing and Exporting Configuration Files.
    4. Click OK to save your changes and to return to the SDI Component Editor.

  6. Click the button to import all or part of the SDI component configuration from a file or to export the entire configuration to a file.

    This option provides you with an easy mechanism for quickly configuring the component using information that comes from an external source without manually entering all the information in the component editor. For more information, see About Importing and Exporting Configuration Files.

  7. Click OK to save your changes and to close the SDI Component Editor.