Just in case, be aware that MAX_MEMORY is per rank, i.e. you need to increase the memory if you use more OpenMP threads in favor of MPI ranks. Do you also have a timing report? This may also help to investigate. Usually, CUTOFF and REL_CUTOFF are less important with the Hartree-Fock-kernel, it is commonly more about EPS_DEFAULT, EPS_PGF_ORB or EPS_SCHWARZ.<br /><br /><div class="gmail_quote"><div dir="auto" class="gmail_attr">Lorenzo Lagasco schrieb am Dienstag, 28. April 2026 um 16:30:01 UTC+2:<br/></div><blockquote class="gmail_quote" style="margin: 0 0 0 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div dir="ltr"><div>Ok, maybe I can test a bit more carefully the EPS_DEFAULT and EPS_ORB (I have already launched different tests for checking convergence on NGRIDS,CUTOFF and REL_CUTOFF). Meanwhile, this is my slurm submission script:<br>#!/bin/bash<br>#SBATCH --job-name=HSEO6<br>#SBATCH --nodes=1<br>#SBATCH --ntasks-per-node=52<br>#SBATCH --partition=taras2-6230r<br><br>module purge<br>module load cp2k/may2025-gnu14.2.0-openmpi4.1.6-psm211.2.230<br>export OMP_NUM_THREADS=1<br><br>mpirun cp2k.popt -i DYE+SLAB.inp -o DYE+SLAB.out<br><br><br></div>I tried to increase the number of OMP_NUM_THREADS from 1 to 2 or 3 and, as a result, the time required for each scf step is longer and longer. Moreover, I regulated the MAX_MEMORY in relation to the memory free of the node. </div><br><div class="gmail_quote"></div><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Il giorno mar 28 apr 2026 alle ore 16:00 Frederick Stein <<a href data-email-masked rel="nofollow">f.s...@hzdr.de</a>> ha scritto:<br></div></div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div>Dear Lorenzo,</div><div>Are you sure that you need these tight cutoffs (EPS_DEFAULT and especially EPS_PGF_ORB)? Can you check how many integrals are recalculated (check the output file)? If they are, is it possible for you to increase MAX_MEMORY? How are you running CP2K (number of MPI ranks, number of OpenMP threads)?</div><div>Best,</div><div>Frederick</div><br><div class="gmail_quote"><div dir="auto" class="gmail_attr">Lorenzo Lagasco schrieb am Dienstag, 28. April 2026 um 15:43:45 UTC+2:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div><div><div></div></div></div><div><div><div><div dir="auto"><div><div><p>Good afternoon everyone,</p>
<p>I am writing to ask for advice on how to improve the computational efficiency of an HSE06 calculation used to evaluate inter-state couplings between diabatic states in a slab–organic dye system (using the Kondov diabatization scheme, system containing 395 atoms). I have attached the input file for reference. In a preliminary test on a CPU-only machine (single node with 52 processors), a single SCF iteration takes approximately 30 minutes.</p>
<p>Any suggestions would be greatly appreciated.<br><br></p><p>Best regards</p><p>Lorenzo Lagasco</p></div></div></div></div></div></div><br><br></div>
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