[Pw_forum] q-grid generation in phonon calculation

[Aaditya Manjanath]

Dear users and developers of Quantum Espresso,

I am using espresso-4.3.2. I was looking at the code to generate the
Monkhorst-Pack grid of q-points for the phonon calculation (in the
PH/q_points.f90). It calls a subroutine kpoint_grid to calculate the grid
of q-points for the specified values of nq1, nq2 and nq3 in the *.ph.infile.
I then checked the kpoint_grid subroutine (PW/kpoint_grid.f90). This is the
same subroutine that calculates the k-point grid for the SCF calculation.

I ran the scf calculation to obtain all the k-points generated in the first
BZ, I found to my surprise, that the k-points generated by pw.x and ph.x
are not the same.

I would like to know the reason behind this or what sort of an operation
has been done to get this difference.

Any help in this regard, would be appreciated.

Many thanks in advance

Cheers,

Aaditya

-- 
Best Regards,
Aaditya Manjanath
PhD Engineering Programme
Interdisciplinary Program - Nanoscience and Engineering
Indian Institute of Science
Bangalore - 560012

Webpage - http://mrc.iisc.ernet.in/~abhishek/Aaditya.html
Email ID -  aadipotter at gmail.com
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