Use Formula Editor Options

There are several options available to you as you create formulas. The following sections discuss each of these options.

Calculate Derivatives

The JMP Formula Editor can find and display the derivative of a function. The derivative is found with respect to the function argument (a single variable name) you highlight. Therefore, in order to differentiate with respect to x, x must be one of the arguments in the expression. The red triangle menu found above the keypad contains the Derivative command.

To calculate a derivative

1.	Enter a function.

2.	Highlight a variable.

3.	Select Derivative from the menu. Using the Derivative Option shows the completion of these steps.

Using the Derivative Option

Simplify Complex Formulas

When the Formula Editor contains a complex formula, JMP can simplify it using various algebraic rules. It can find constant expressions, distribute multiplication over addition, combine terms, and more.

To simplify complex formulas

1.	Select a portion or all of the formula.

2.	Click the red triangle menu above the keypad.

3.	Select Simplify from the menu that appears, as shown in Selecting Simplify (Left) Produces a Simplified Formula (Right).

Selecting Simplify (Left) Produces a Simplified Formula (Right)

Evaluate Formulas

By default, JMP evaluates each formula that you create. You can turn this evaluation off, or you can use it before you have finished creating a formula.

Suppress Evaluation

Turning off evaluation is a useful formula development mode for building complex formulas. You can turn off evaluation and build sections of a formula, and evaluate only to test it. In particular, you can close the Formula Editor and reopen it at a later time to continue building a formula without JMP evaluating it.

To suppress formula evaluation, click the red triangle menu above the keypad and select Suppress Eval. When evaluation is suppressed, the formula icon appears dimmed

Note the following:

•	If the icon appears to the right of the red triangle menu in the Formula Editor, it indicates that formula evaluation is suppressed for that formula.

•	If the icon appears beside the column name in the Columns panel, it indicates that the values in the column result from a formula. When formula evaluation is suppressed, this plus icon becomes gray. (For details, see Icons Representing Column Characteristics and Properties in Get Started.)

Note: The Apply button ignores the formula evaluation setting. Therefore, when formula evaluation is suppressed, clicking the Apply button overrides the suppression and evaluates the formula before it is applied to the column.

Ignore Errors

Once you construct a formula and click OK, JMP checks behind the formula for error and alerts you of any errors that it finds. An error message appears for each error and asks whether you want to ignore further errors.

Sometimes you might want to suppress error messages while a formula is under development. For example, you might want the evaluated values for some rows without seeing an error message for each row that causes errors.

To have JMP ignore any errors

1.	Create a formula.

2.	Click the red triangle menu above the keypad and select Ignore Errors.

View a Formula’s Values from the Formula Editor

While in the Formula Editor, you can see the value of any expression within a formula with the Evaluate command. For column variables, you get the value at row 1. This is also true for parameters and expressions that evaluate to a constant value. To view values:

1.	While in the Formula Editor, select the expression that you want to know about.

2.	Right-click the selected expression.

3.	Select Evaluate. The current value of the selected expression appears in a box until you move the cursor.

View a Formula in JSL

You have the option of entering or changing any part of a formula in text mode. Text mode displays the formula in JMP Scripting Language (JSL). The entire formula (or any of its terms) appears in text mode when you double-click the white space inside the boxed formula area. The elements of that box appear as plain text and you can then edit the formula as you would in any text editor.

Any element of a formula can be displayed as a scripting command and then edited. After editing formula scripting commands, click outside the formula to see its formatted form. For example, the text for the standardization of weight is (:weight – Col Mean(:weight)) / Col Std Dev(:weight). To enter an If statement in text form, add pairs of arguments for each If/Then clause in the statement, and a single last argument for the else clause if needed. In text form, the If statement in An If Statement in Formula Mode looks like this: If(:total!=0, (:count/:total)*100, 0).

An If Statement in Formula Mode