Declaration: 
TIlabTrnDataSet.CountDuplicates: integer; 
The function CountDuplicates counts all duplicates from the data set and returns their number. Please note that a data point (see TDataPoint) is regarded to be duplicate if both the x and the y coordinates are the same.

Hint: 
The search for duplicate data points may fail if the x and y coordinates are rational numbers (due to rounding effects). 
