A hybrid calculation with k-points requires, in addition to all other terms for ordinary DFT, the computation of the exact-exchange term costing O(Nk*Nq*Nb*Nb*Nw) floating-point operations, plus the storage of Kohn-Sham states, filling Nq*Nb*Nr double precision complex numbers. Legend: Nk = number of k-points in the Irreducible Brillouin Zone (301 in your case) Nq = number of k+q-points (1728) Nb = number of Kohn-Sham states (53) Nw = number of plane waves (20005) Nr = number of points in the FFT grid = nr1*nr2*nr3 = 72*72*72 Arrays and computations are distributed so divide Nw and Nr by the number of processors. If I made the math correctly, it's 2.65 Gb RAM per MPI process on 192 processors. I am not surprised it crashes. Even if it doesn't, it will take approximately forever. Are you sure you need that many k- and q-points?
Paolo On Wed, Jan 6, 2016 at 9:32 PM, Dumett Torres, Daniel <[email protected] > wrote: > I have been trying to run a hybrid PBE0 calculation in parallel and have > run into a recurring problem in which the calculation stops after scf > convergence is first acheived - the calculation stops and doesn't go on to > refine the calculation with exx. I have tried to run the calculation with > between 24 and 192 processors because we previously thought memory > requirements were to blame for the error, but this didn't seem to help. > > *''**TACC: Setting up parallel environment for MVAPICH2+mpispawn.* > *TACC: Starting parallel tasks...* > > * Program PWSCF v.5.2.0 *' > > > *'Parallel version (MPI), running on 192 processors* > * R & G space division: proc/nbgrp/npool/nimage = 192*' > > > *'highest occupied, lowest unoccupied level (ev): 6.3409 6.0501* > > *convergence has been achieved in 16 iterations* > > *TACC: MPI job exited with code: 1* > > *TACC: Shutdown complete. Exiting.'* > > > this error produces a CRASH file that reports an error reading an xml-data > file and upon inspection,the .save folder produced contains the > charge-density.dat file but is missing the .UPF files, the data-file.xml > file, and data-file.xml.eig file. Furthermore, while the .igk files have > content, all the .wfc files produced by the job are empty (0 bytes). My > impression is that this missing content is what is keeping the calculation > from being able to proceed but I don't know how it might be addressed. > > attached is the input file for my calculation. Attached are the input and > output files resulting from one such run. I did notice an additional > message in the output > > *' Message from routine sym_rho_init:* > * likely internal error: no G-vectors found'* > > but the calculation seems to proceed despite it... > > I appreciate any insights you might have regarding these complications I > am facing > > Thank you for your help, > Daniel Dumett Torres > Graduate Student at the University of Illinois at Urbana-Champaign > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum > -- Paolo Giannozzi, Dip. Matematica Informatica e Fisica, Univ. Udine, via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222
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