DX program searches for doublets of peaks in a single mass list text file.
Mass lists have to be stored as single columns of values in .txt file. 
Input file names do not require neither directory root or extensions.
Mass difference value have to be stored in the DX_Controls.txt file and occupy leftmost position of the first string followed by a space.
Second string of the DX_Control.txt file contains tolerance value in Daltons for determining of doublets.
All files need to be in the same directory.
Doublets if found will be stored in associated with mass list _DX.txt result file.