[Pw_forum] problem calculating electron - phonon matrix elements , stars of points grid

[Abderrezak TORCHE]

Dear users ,
I am having a problem in calculating the electron phonon coupling
coefficients for  trilayers graphene in ABA stucking, the systeme have
no inversion. The problem is : when ph.x write the
${prefix}_elph.mat.q_${q} files the number of q points in the star do
not include the -q points but during the calculation of the dynamical
matrices and the DVSCF's  the symetrie is used (inversion), so for
example in 6 x6 grid we found 7 irreducible points but if one compute
the number of q points in the stars of these q points without
including the -q points he will not find 36 points.
Is there any suggestion to avoid this problem, I mean to write in the
electron_phonons coupling files all the q and -q points.

thank you in advance.



Abderrezak TORCHE
PhD student , UCL , Belgium.