Generate a set of similarity scores between sets of sequences.  
You will be prompted for 
a) the set of sequences that form the query (default to the
   current sequence), 
b) the set of sequences that form the library (default to the 
   current sequence),
c) the regions of the sequences that are to be used in the calculation, and 
d) the method of output.
The scores may be use in three ways, selected via a menu: 
a) send scores to the SCREEN,
b) send scores to HPLOT, so they may be displayed 
   graphically as a frequency histogram, or
c) sent to a file (enter just the file name).
If the variable IGNORE-SELVES-IN-SIMILARITY is set,
comparisons of a sequence against itself will be ignored.