==================== User Function Dialog ==================== The User Function dialog helps in editing the ``Formula`` attribute of :ref:`UserFunction `. It offers a list of functions that can be used, helps to resolve parameter name clashes, allows to save frequently used formulas. .. image:: /images/Workbench/UserFunctionDialog/UserFunctionDialog_main.png :scale: 70% :align: center The upper half of the dialog provides access to the built-in and saved custom functions. There are three text panels there. The ``Category`` panel contains a list of categories the functions are divided into. Clicking on a category shows names of all functions in this category in the next "Functions" panel. The next panel ``Expression`` displays the mathematical expression for a selected function along with a brief annotation. The lower half of the dialog contains a multi-line text editor for typing in and editing the formula. The formula must be a valid muParser expression and a function of single argument x. Any other variable is treated as a parameter. The parameters are automatically extracted from the formula and displayed in read-only text field "Parameters". Button ``Add`` inserts the function selected in Functions list to the formula at the current caret position. This is most useful to load a previously saved formula. If a saved formula is used in a larger expression parameter name clashes are possible. In this case a dialog will pop up offering to rename the parameters of the new expression. There are three options: - leave the names as they are, - add an index or - rename manually in "New name" column. The finished formula can be saved for re-use by clicking the ``Save`` button. A dialog will pop up and offer to select the category, define a name and description for the saved function. After saving the function will be available for the ``Add`` button. The ``Remove`` button allows to remove a previously saved formula. After editing is finished click ``Use`` button to use the expression in UserFunction.