[Pw_forum] inverse participation ratio

[Paolo Giannozzi]

Roberto Guerra wrote:

> this is the formula:
> http://ulisse.fisica.unimo.it/ipr.png
> where "i" is the index of the volume element.

I guess a multiplication by the volume element (Omega/N if Omega is
the volume of the unit cell) is missing.  For norm-conserving
pseudopotentials, the denominator is always equal to 1. For
ultrasoft pseudopotentials youy should verify whether such a
formula is still valid.

> What do you think is the best way to code such a thing?

the "monkey way" is the best:  modify one of the postprocessing
codes. For instance, case 7 in code PP/pp.x. Copy what you need
for instance from PP/localdos.f90 (ignore what you do not need)

P.
-- 
Paolo Giannozzi, Democritos and University of Udine, Italy