Author: Benjamin J. Morgan Date: November 13, 2013
This program calculates local strain fields from VASP / QUAIM ionic configurations.
This routine is based on the algorithm proposed by M. L. Falk and J. S. Langer and borrows heavily from the MATLAB implementation by P. Schall and D. Bonner; used in, for example, Rahmani et al. Sci. Rep. 2, 1064 (2013).