Define Input Variables

In the Define Input Variables step:

For many model types the input variables are imported directly from the model without user interaction, however some model types require you to select input variables.

1.	In the Define models step, click Import Variables. The Model Parameter Tree dialog opens.

Note:

This dialog allows certain parameters from the parent HyperMesh or MotionView session to be defined as input variables in HyperStudy.

The left-hand panel displays the parameters in the parent model which are available for definition as HyperStudy input variables.

The right-hand panel displays the parameters you have selected for definition as input variables. You will define these parameters once you click OK (HyperMesh) or Done (MotionView).

motionviewimportdvs

Model Parameter Tree dialog in MotionView

hypermesimportdvs

Model Parameters dialog in HyperMesh

2.	Select the parameters you wish to define as input variables.

Note:

For HyperMesh models, you can edit the upper and lower bounds of the input variables at this step.

3.	Click Add. The selected parameters are appended to the right-hand panel.

4.	Click OK (HyperMesh) or Done (MotionView). HyperStudy adds the parameters that were listed in the right-hand panel to the list of input variables for the current study.

Note:

Each model parameter is associated with an input variable.

Before importing variables from an Excel Spreadsheet, it is important that the they are formatted correctly. A variable's value and label can be formatted in two consecutive rows or two consecutive columns. Variable labels should only contain English characters, or a combination of English characters and numbers. If you do not create a label for a variable, HyperStudy will assign one by default.

1.	In the Define models step, click Import Variables. The Excel - HyperStudy dialog and the Excel spreadsheet open.

2.	To begin selecting input variables, click Yes. The Excel - HyperStudy Input Selector dialog opens.

hs_1035_excel_dialog

3.	In the spreadsheet, select the input variable's value and label cells. The cells you select in the spreadsheet appear in the Excel - HyperStudy Input selector dialog.

Note:

You can select an input variable's value and label in two consecutive rows or two consecutive columns.

exceldesignvariables

4.	Click OK to import the selected input variables.

5.	Optional: To continue selecting more input variables in other areas of the spreadsheet, repeat steps 3 and 4.

6.	To stop selecting input variables, click Cancel. The Excel - HyperStudy dialog opens.

7.	Click No or Yes according to your needs.

No:	To return to HyperStudy.
Yes:	Proceed and begin selecting output responses. The Excel - HyperStudy dialog closes and the Excel - HyperStudy Output selector dialog opens.

8.	In the spreadsheet, select the output responses' value and label cells. The cells you select in the spreadsheet appear in the Excel - HyperStudy Output selector dialog.

Note:

You can select an output responses' value and label in two consecutive rows or two consecutive columns.

9.	Click OK to import the selected output responses.

10.	Optional: To continue selecting more output responses in other areas of the spreadsheet, repeat steps 8 and 9.

11.	To stop selecting variables and return to HyperStudy, click Cancel.

You have now imported input variables and output responses from an Excel spreadsheet to your current study.

1.	Create input variable.

2.	In the Define Input Variables step, click the Define tab.

3.	Click Add Input Variable.

4.	In the Add - HyperStudy dialog, enter a Label and click OK.

Note:

Variable labels should only contain English characters, or a combination of English characters and numbers. If you do not create a label for a variable, HyperStudy will assign one by default.

Tips:

Add multiple input variables simultaneously by pressing and holding Add Input Variable. In the pop-up dialog, enter the number of input variables to add and press Enter.

add_dvs_simultaneously

1.	In the Define Input Variables step, click the Define tab.

2.	In the work area, click the input variable to remove.

3.	Click Remove Input Variable.

In the Define Input Variables step, Define, Details, Distributions, or Links tab, clear an input variable's corresponding checkbox in the Active column of the work area.

Once a input variable's checkbox is cleared; that is, made inactive, it is no longer a variable but is fixed to its initial value.

input_variable_activate_deactivate

In the Define Input Variables step, input variable properties can be modified in the Define, Details, and Distributions tabs.

Bounds

•	Lower bound. The lower limit of the variable range to be studied.

•	Nominal. The default value of the variable if deactivated; also serves as the initial value in an optimization.

•	Upper bound. The upper limit of the variable range to be studied.

Data Type

•	Real. Variable stored as a real valued floating point number, for example 1.0.

•	Integer. Variable stored as an integer, for example 1.

•	String. Variable stored as a character without any numeric meaning, for example one.

Mode

•	Continuous. Input variable that can take any value between the lower and upper bounds, for example 1 < x < 2.

•	Discrete. Input variable that can take values from an orderable finite list of numeric values, for example x = 0.1, 0.2, 0.3, or 0.4.

1.	Click the Details tab.

2.	In the Mode column, select Discrete.

Note:

The Values cell turns orange, which indicates can edit its values.

discrete_input_variable_define_2

3.	In the Values cell, click .

4.	In the dialog, edit the discrete value set.

a.	Add content to this set by clicking Add Row; remove content from this set by clicking Remove Row.

b.	To divide the value range into equal segments, change the lower and upper bounds, enter a value in the Step Number field, and then click Set.

c.	To create a set with equal step sizes, change the lower and upper bounds, enter a value in the Step Size field, and then click Set.

d.	Click OK to accept the changes made.

discrete_input_variable_define

•	Categorical. Input variable that can take values from a non-orderable finite list of values, for example x = red, green, blue.

1.	Click the Details tab.

2.	Set Data Type to String.

3.	Set Mode to Categorical.

The Values cell turns orange, indicating the values can be modified.

mode_categorical

4.	In the Values cell, click .

5.	In the dialog that opens begin defining categorical values.

define_design_variable_categorical_values

6.	Click Apply.

Click OK.

Distribution Role

•	Design. Variable that is deterministic and has no uncertainty associated with its value.

•	Radom Parameter. Variable that is probabilistic, but is not controllable by design; for example wind speeds or temperature.

•	Design with Random. Variable that is probabilistic, but is controllable by design; for example thickness or radius.

Distribution

See Statistical Distributions

Reduce the number of independent variables and/or of different models in multi-model studies in order to have synchronized design updates between models by linking input variables to each other. The input variable of a model can also be linked to the output responses of other models. If the input of a model is a function of outputs of other models, you can add an input variable for the input of the dependent model and responses for the outputs of the independent models, and link the input variable to the output responses by entering the dependency in the expression field.

For an example on linking input variables, refer to HS-1060: Linking Variables of a Model to Output Responses of Other Models.

In the Constraints tab you can define an inequality constraint condition that is a function of only the input variables. Because this special constraints can be evaluated when performing any solver execution, they can be treated in a special way to ensure that no evaluations are generated that violate the condition. For example, you can fill a space that ensures that no design violates the condition, or an optimizer can avoid generating evaluation runs that would be known to generate a solver failure.

1.	Click Add Constraint.

2.	In the Add-HyperStudy dialog, enter a Label and click OK.

3.	Specify a Left Expression and a Right Expression to compare.

Manually enter an expression, or click to create an expression in the Expression Builder.

4.	Select a Comparison type: Greater than or equal (>=) or Less than or equal (<=).

Define Input Variables

Define Input Variables

Define Input Variables

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