Defining Problem Formulations

You can define a general problem formulation that you want to solve by setting the bounds and objectives for parameters on the Formulation tab in the Design Gateway or on the Parameters tab in the Runtime Gateway.

If you subsequently change the parameter attributes (i.e., lower bound, value, upper bound, objective, and target), the parameters in the corresponding component inherit the new values (see About Design Parameters Initialization).

  1. Do one of the following:

    • From the Design Gateway,

      1. Open a model or create a new model, and select a process component.
      2. Click the Formulation tab.

    • From the Runtime Gateway,

      1. Open a model, and select a process component.
      2. Click the Parameters tab.
      3. Click Show problem formulation, if needed.

    The design parameters for the selected component appear.

    Note: Only numeric parameters (i.e., real or integer data types) are displayed because the parameter attributes in the problem formulation are numeric in nature.

  2. If desired, select which columns you want displayed on the Formulation or the Parameters tab. Click the button located on the scroll bar, and select a column name to have it displayed or hidden. A checkmark next to a column name indicates that the column will be displayed. Select All to show all the columns.

  3. Set the following options, as desired.

    Option Description
    Lower Enter the value that you want to define as a lower bound or limit.

    Note: If the current value is less than the defined lower value, this cell is colored pink to indicate that your current design does not conform to the stated problem formulation.
    Value Enter the initial value for the parameter.
    Upper Enter the value that you want to define as an upper bound or limit.

    Note: If the current value is greater than the defined upper value, this cell is colored pink to indicate that your current design does not conform to the stated problem formulation.
    Objective Specify whether you want to minimize or maximize this parameter or try to achieve a target value.
    Target If the Objective is set to target, enter the value that you want to try to achieve.
    Objective Scale Enter the value that you want to use as the scale factor for this parameter when it has an objective defined.
    Objective Weight Enter the value that you want to use as the weight factor for this parameter when it has an objective defined.
    Bound Scale Enter the value that you want to use as the scale factor for this parameter when it has bounds or constraints defined.
    Bound Weight Enter the value that you want to use as the weight factor for this parameter when it has bounds or constraints defined.

    Note: If a value violates a constraint on a parameter, Isight colors the cell red on the Parameters tab in the Runtime Gateway.

  4. To clear the problem formulation for any parameter in the Design Gateway, select the parameters in the table, right-click, and select Clear problem formulation for selected.

  5. To edit multiple parameter values simultaneously in the Design Gateway, select any number of parameters and click .

    The Edit Problem Formulation dialog box appears.

    1. Click the attributes that you want to edit. You can edit the Lower, Upper, Objective, Scale, and Weight values for all selected parameters at once.
    2. Enter the value in the corresponding text box.
    3. Click OK to save your changes.

      Isight places the values that you entered into the corresponding columns for each selected parameter.

  6. To view the impact in the Runtime Gateway, click the History tab.

    Isight uses color coding to display problem formulation information on the History tab (see Understanding Run Grading.

  7. Execute the model, if desired.