How single and multiline modes work 



Single line mode This mode restricts the math input to a single line. It is designed so that many calculations can be done quickly, as you would with a normal calculator. Press the return (enter) key to evaluate your expression.You can also click the = button with the mouse, or use the hot key "Command =". If the perform calculation when = pressed is selected in the Preferences, then formula calculator also evaluates the expression when you press the equals key on the keyboard. Once evaluated, the input expression is highlighted so that another expression can be typed directly over it. Define your own function in this mode by simply typing it in and pressing return. Functions are defined by a name, brackets, one or more parameters separated by commas and an equals sign, such as myFunc(this,that)=thisthat. Formula calculator recognises this as a function definition and asks if you want to keep it,. The function is saved in the user functions list. You can see this function in functions list (see Lists and keypads) where you can give it a description and elect to delete it when no longer wanted. Once saved, the function can be used in any expression. Multiline mode This mode is designed for more complex arithmetic expressions, where you evaluate many different parameters that depend on other parameters. Each time you press the return key, formula calculator evaluates every expression, line by line, starting at the top. It displays the results of every expression. You make the results field larger by dragging the divider just below it. A function can be defined just as in the Single line mode. While it remains in the math input text field it is available for all expressions that appear after it. If you want to save it you need to go to the functions list, select your function and check the keep for next time box. You can also type a description of your function. When in fixed order mode it is important that parameters have values before they appear in subsequent expressions, otherwise formula calculator cannot evaluate the expression. For example
cannot be evaluated since formula calculator will try to perform 2*x before x has a value. In this case you should interchange the order of the two expressions. In any order mode, you can type your equations in any order. Formula calculator processes the equations from top to bottom and evaluates all expressions that have values. It then repeats, processing the equations from top to bottom and tries to evaluate the expressions again. In most cases, many of the parameters encountered on the first iteration will now have values and can be evaluated. This proces is repeated until formula calculator cannot evaluate any more expressions. Because the equations are evaluated multiple times, this mode is slower. For very complicated expressions using large arrays of numbers it is more efficient to use the fixed order. 
