Enter Calculation

The Enter Calculation option in the Data menu or the main toolbar is used to enter one or more equations for data transformation. A calculation consists of mathematical equations that transform one or more of the variables within the X-Y data table. In a calculation, the X, Y, or weights data table values are treated as vectors and simply referenced as X, Y, and W. Although the transforms generally consist of X= a function of X, or Y= a function of Y, you can also create simple data sets where Y= a function of X. A calculation is a global transform that will be offered for use on all subsequent imports until the Cancel Calculation option is used.

Sample Calculations

Some example calculations are:

X=(1/X)*1E7 This calculation transforms X as a wavelength in nm to wave number in inverse centimeters.

Y=LOG(100/Y) This calculation converts Y as % transmission to absorbance.

Y=Y+GNOISE(5) This calculation adds 5% random Gaussian noise to a data set.

Entering an AutoSignal Calculation

An AutoSignal calculation consists of an X= expression, a Y=expression, and a W= expression. Only one expression need be present in a calculation. You may enter any numeric calculation. All of the functions and constants available within AutoSignal can be accessed via a special Function Insert help.

The X=, Y=, and W= prefixes are automatically supplied. If you enter a calculation with multiple cross references to X and Y, bear in mind that the X calculation will be applied first, then the Y, and finally the weight calculation.

Copy, Cut, Paste

Use these buttons to paste in expressions from the clipboard, or to modify the text across the various fields.

Read

Calculations that have been saved to disk are read by using the Read button. It is a good idea to save a calculation that will likely be used on future data sets. Calculation files are binary files with [CLC] extensions. They can be created only within the program.

Save

The calculation active at the close of any given session is not automatically saved across sessions. You must explicitly save a calculation to disk using the Save button in order to have it available in a future session.

Validation

The calculation will be validated when you exit the Calculation entry screen. If there is an error in any of the expressions, an error message will report a specific parser or math error and you will be shown where within the expression the evaluation failed. The cursor will also be placed at this position. Note that a calculation must be defined at the Xmean and/or Ymean of the data table or at values of 1.0 if the data table is empty. Calculations are compiled for a very rapid processing with large data sets.

Option to Apply

You will be given an option to immediately Apply the Calculation you have entered to the current data table. Answer No if the calculation is to be applied only to additional data that will be appended to the current table.