[Pw_forum] For B pseudopotential

[sprokuda at dnk.ru]

Dear PWscf users!
I wanna ask you a question, which has no direct concern to PWscf.
Generally my problem in to computer the eigenvector for bulk
Germanium. I'mv short in time with this problem, and causeof that I've
tried to use the code from
O.H. Nielsen, W. Weber,     Computer Physics Communications 18 (1979) 101-108.

It is based on bond-charged model and gives good results for frequencies, which are the result of the solution eigenvalue
problem for dynamical matrix (6*6 size for Ge).
As for eigenvectors the results seems strange and wrong. 
First - the results of eigenvectors is strongly compilier dependent -
that is my firsr question - how it could be and what could be reason
for that?
Eigenvector here is a complex vector of 6*1 size. First three digits describes eigendisplasement of first atom in unit
cell, second three digits describes eigendisplasement of second atom. For each three e1 and e2 the condition must be
satisfied: e1,2 = c1,2*exp(-i*phi1,2), where e1,2 is the eigendisplacement, c1,2 is a real vectors of dimention 3*1, i -
imaginary unit.This condition is not satisfied . More in detail, in some cases this condition is satisfied,  but there only
in some points along [q q 0] direction.
The second question what could be the reason for such a strange behavior of comutation of eigenvectors (while the results for
frequencies is rather good)?.
The numerical routine for the solution of  eigenvector problem is
well-tested, namely I use for that IMSL numerical library.

I would be greatly thankfull for any information of suggestions.
Best wishes, Sergey Prokudaylo.