bobbypaton/compchem — pull request #1 by kelvinjackson (2014-07-11 14:20:28+00:00)
Title: Update weightednmr.py

Previously the script was unable to handle symmetric systems in which either x or y coordinates have opposing signs equidistance from the x- or y-axis causing xsum and ysum to run to zero; this would result in the generation of a vector parallel, rather than perpendicular, to the plane.