Dear Xavier,


30–40 times faster is indeed a very pleasant result 😊. The reason is that the PyNEST interface induced MPI communication for each of the weight updates, and if 64 ranks need to sync all the time, the going gets slow.



Hans Ekkehard




Prof. Dr. Hans Ekkehard Plesser


Department of Data Science

Faculty of Science and Technology

Norwegian University of Life Sciences

PO Box 5003, 1432 Aas, Norway


Phone +47 6723 1560






From: Xavier Otazu <>
Date: Monday, 12 February 2024 at 15:12
To: <>
Subject: [NEST Users] Re: Weights assignment error with mpirun

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A small clarification ... I always used 64 mpi processes to run my code (hence, the 30-40 speedup performace is because of your new code).

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