In DM2003, Calculator Dialog has several functions. First, unlike standard Windows calculator, this tool allows you to evaluate arbitrary expression that may depend on the set of variable parameters (see expression syntax for more information about available functions and operators). You may change values of a..z parameters using Parameters table and calculate result for several parameter sets.
Another application of the Calculator Dialog related to the Plot and Worksheet calculator tools. These tools use expression defined in the Calculator Dialog that can be evaluated for clicked plot point or selected worksheet line.
For plot calculator, values of cx and cy parameters are X and Y coordinates of the clicked plot point. Unlike the case of serie expressions, in Calculator cx and cy parameter values are not X/Y column values but the actual coordinates of the clicked point.
For worksheet calculator, values of a..z parameters are copied into the parameter table from the columns of the selected worksheet line (cx and cy are just aliases for columns marked as X and Y, and only existing columns are copied). This tool works exactly as if you would click "Evaluate" button in the Calculator dialog, but the Parameters table specially filled before calculation. If you select more than one line, Worksheet calculator will be disabled.