<div dir="ltr">Hi, Sorry I did not get an answer to the issue so far, and I did not work on it to figure the problem out. But I would be really happy, if someone else could find a suitable answer to the problem. Let me know, if you are more successful. Best wishes and good luck Tobias Am Donnerstag, 25. Oktober 2018 14:18:04 UTC+2 schrieb tobias...@gmail.com:<blockquote class="gmail_quote" style="margin: 0;margin-left: 0.8ex;border-left: 1px #ccc solid;padding-left: 1ex;"><div dir="ltr">Dear all, I want to perform a nudged elastic band (NEB) calculation using cp2k. I get the "CPASSERT failed", when I try to calculate too many replica at once. Does anyone know the difference between the "Number of Images" and "Number of Replicas"? Does anyone have experience, how to choose the number of processors per replica NPROC_REP and the number of calculated replica NUMBER_OF_REPLICA for the best performance? Is there a thump rule, how many Open MP threads to use for best performance? I tried to match the total cpu cores with nproc_rep * number_of_replica but the number_of_replica input seems to be ignored, instead cp2k uses the number of intermediate structures (replicas) as number of images. When I use 6 replicas and 12 nproc_rep the calculation runs on the 72 core node. however I set the number of replicas to 6 and provided 6 structures. CP2k now gives as output: Number of Images : 6 ** ** ## ## ######### ## #### ## ## Number of Replicas: 1 ** ** ## ## ## ## ## ### ## ## Number of Procs/Rep: 12 Why does it change the number of replicas during the run? When I use 9 replicas and 8 nproc_rep the calculation does not run, but as far as I understand the input should work this way. Best wishes Tobias </div></blockquote></div>