[Pw_forum] Clarification of a confusion related to q vector specifications in ph.x

[Vikas Varshney]

Dear QE usesrs,

I wanted to have a clarification on the following sentence from the
phonon calculations part of the manual: "After the namelist you must
specify the q-vector of the phonon mode. This must be the same
q-vector given in the input of pw.x.". The link for the following text
is given below.
http://www.quantum-espresso.org/user_guide/node31.html

In ph.x, we specify three values for q-vector (0,0,0) for gamma point,
for example.

However, in pw.x, the k points are often specified as

K_POINTS automatic
4 4 2 0 0 0.

I wanted to understand if these are related. If not, what does the
above sentence mean. I am not sure but it might be a silly question to
ask but I am trying to clear it in my head.

Any insights will be highly appreciated.

Best Regards,

Vikas Varshney
Computational Materials Scientist,
Wright Patterson Air Force Base,  Dayton OH