# Dequations Panel

Use the Dequations panel to create user-defined functions for responses and design properties.

Location: Analysis page > Optimization panel
Note: Only available in the OptiStruct solver interface.

## Guidelines for Entering Equations

• Each dequation definition may consist of one or more equations, which are separated by semicolons ( ; ). A semicolon must not follow the last equation.
• The first equation must take the following form:

$f\left({x}_{1},{x}_{2},...{x}_{n}\right)$ = (some mathematical expression referencing all of the variables ${x}_{1},{x}_{2},...{x}_{n}$ )

• Subsequent equations may reference the resultant variables of the previous equations in the following manner:

${f}_{1}\left(x1,x2,...xn\right)$ = (some mathematical expression referencing all of the variables ${x}_{1},{x}_{2},...{x}_{n}$ )

${f}_{2}$ = (some mathematical expression referencing ${f}_{1}$ )

${f}_{3}$ = ...

...

${f}_{n}$ = (some mathematical expression referencing ${f}_{1},{f}_{2},{f}_{3},...{f}_{n-1}$ );

• Constants may be specified as integers or in a floating-point format. A floating-point number can be in a format of either normal decimal-point format (3.90) or scientific notation (2.0E-3.0).
• Only alphanumeric characters may be used in variable names. ( You may not use underscores, monetary symbols, punctuation symbols, or mathematical operators in variable names.)

## Panel Options

Option Action
dequation Name for the dequation definition (max. 8 characters).
edit equation Enter the function or functions. The functions must follow the guidelines listed in Guidelines for Entering Equations.

## Command Buttons

Button Action
create Create the dequation.
update Update the dequation.
review Review the dequation.
clear Clear the selection.
prev Move the previous page of equations.
next Move to the next page of equations.
return Exit the panel.