Hello Christoph, it is indeed a good question. I will also take a look at the table w.r.t. inter-communicators. It may have similar caveats for collectives with inter-communicators. Best regards, Julien J. ________________________________ De : mpiwg-hw-topology <[email protected]> de la part de Christoph Niethammer via mpiwg-hw-topology <[email protected]> Envoyé : mardi 18 mars 2025 09:15:23 À : mpiwg-hw-topology; [email protected]; MPI-3 Collective Subgroup Discussions Cc : Martin Schulz Objet : [mpiwg-hw-topology] Discussing Semantics and Synchronization Requirements for Neighbourhood Collectives Hello everyone, During the preparation for the FRM, a question was raised regarding whether and how the semantics of collectives apply to neighborhood collectives. [1] This question stemmed from remark 18) in the summary table in Appendix A. 2, ZjQcmQRYFpfptBannerStart This Message Is From an External Sender This message came from outside your organization. ZjQcmQRYFpfptBannerEnd Hello everyone, During the preparation for the FRM, a question was raised regarding whether and how the semantics of collectives apply to neighborhood collectives. [1] This question stemmed from remark 18) in the summary table in Appendix A.2, which was used to apply the semantics of collectives to neighbourhood collectives at this place. The discussions expanded during the March meeting to the question of whether remark 18, stating that "all-to-all collectives *must* synchronize (with some restrictions)", is correct. [2] I would like to invite you all to discuss these two issues in more detail during a Topologies WG meeting on March 27th at 15:00, as part of our regular WG slot. Best regards Christoph Niethammer [1] https://urldefense.us/v3/__https://github.com/mpi-forum/mpi-issues/issues/86... [2] https://urldefense.us/v3/__https://github.com/mpi-forum/mpi-issues/issues/97... -- Dr.-Ing. Christoph Niethammer High Performance Computing Center Stuttgart (HLRS) Nobelstrasse 19 70569 Stuttgart Tel: ++49(0)711-685-87203 email: [email protected] https://urldefense.us/v3/__https://www.hlrs.de/people/christoph-niethammer__...