[Pw_forum] Does dens grid contain the whole carse grid in calculation of EPI?

[whwaniphy]

Hi Quantum espresso users!

I want to learn to calculate electron-phonon constant. The example of Al in exapmel07 shows that it is convenient to use a sparse k-point (nk1*nk2*nk3) grid to calculate the phonons (nq1*nq2*nq3), and use a dense k-point grid (nk1fit*nkfit2*nkfit3) to calculate the sum at the Fermi energy. The latter MUST contain all k and k+q grid points used in the subsequent electron-phonon calculation. A puzzle rises. Dose the vector “k” mentioned above belong to sparse grid or dense grid? The former means i/nk1+j/nq1=k/nkfit and latter means i/nkfit1+j/nq1=k/nkfit1 where i,j,k are integer. Which is right? I found the PWSCF won’t produce Error but produce different results in two cases. .
Suggestions welcome!

Thanks
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