EPW Forum

The only change I made was adding nosym=.true. to the pw.x input files (scf.in scf_epw.in nscf_epw.in) in example t04

There are indeed not 216 qpoint calculations.

Thank you for your quick reply Two reasons: 1) Reuse old dvscf data (these calculations can take very long for larger systems) which was generated before I could make use of symmetry 2) Not all configurations have the same symmetry and it can then be difficult to compare the different modes Perhaps ...

When adding nosym=.true. to scf.in scf_epw.in and nscf_epw.in, example t04 no longer works. My guess is that epw finds the symmetries (as reported in epw.out) and tries to access files/data which is not there: ##########################################################################################...

I don't think you can have a q grid which is finer than your k grid, since you would then get k+q points for which you do not have the electronic wavefunction, so you should always choose nk1=i*nq1 where i is an integer number.

After having used EPW for some time now, I am working on more complicated systems and I get into memory issues. Currently I have a somewhat (apparently) large system: 18 atoms and 178 non-pseudo electrons. It is a 2d system with a kpoint grid of 18x18x1 kpoints. The wannierisation works well after s...