RMS deviation between two sets of cartesian coords

[Doug Gwyn]

In article <27599 at cs.yale.edu> jim at doctor.chem.yale.edu (James F. Blake) writes:
>     I am looking for code to compute the RMS deviation between two
>sets of cartesian coordinates.  The coordinates would be arbitrarily
>oriented with respect to each other, so some sort of fitting would
>be required (LLSQ, NLLSQ, or simplex).

Sounds to me like the sums of the squares of the (vector) differences
between corresponding coordinates would suffice -- or is it the
situation that you can't establish a correspondence between points
in the two sets (i.e. you want to compare clouds as such).