Enter Calculation¶
The Enter Calculation in the Data menu offers the means to transform one or more of the data table variables.
A 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 TableCurve can be accessed via a special Function Insert help. The X=, Y=, and W= prefixes are automatically supplied. When entering 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.
Calculation Types¶
A calculation can be used to change the existing variable. As examples, the expression X=X*2.54 converts X-values in inches to centimeters and the expression Y=(4/3)*PI*Y^3 converts Y-values representing a radius to a volume. A calculation can also be used to calculate one variable based upon another. As examples, the expression Y=Y+1.232+2.323*X+3.3433*X^2+4.3234*X^3 increments the original Y variable by the value of a polynomial in X. The expression W=1/Y assigns weights equal to the inverse of the Y-values.
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. Calculation files have .CLC extensions.
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.
If Background Thread Fitting is active, the fitting will be initiated as soon as the calculation is applied. The fitting will thus be taking place in the background when you are inspecting the result of the calculation in the TableCurve 2D Graph.