Oops. I was wondering what happened to my response, and I did not realize it was subject to approval and posted another attempt at framing the answer. Sorry.
On Tuesday, March 12, 2024 at 2:15:22 PM UTC-7 Petr Krysl wrote: > Good point about Tpetra: I will check it out. > > > SparsityPattern is usually extremely fast > If it is the only sequential of a program executed with multiple threads, > it can still control the scalability. > > Which reminds me: In your WorkStream paper, you do not report the time > taken to construct a sparsity pattern. > Could you tell me how expensive it was compared to the sequential assembly > of the numbers into the matrix? > > Many thanks, > > Petr > > On Tuesday, March 12, 2024 at 12:08:29 PM UTC-7 bruno.t...@gmail.com > wrote: > >> In Trilinos, the Tpetra library has Graph which is basically a >> SparsityPattern. Tpetra uses Kokkos (which abstracts multithreading and GPU >> support) everywhere so I would expect that they use Kokkos to build the >> Graph too. Multithreading for dealii's SparsityPattern is not planned so >> far. It could be done but building the SparsityPattern is usually extremely >> fast compared to the rest of the code and so, it's not worth doing. >> >> Bruno >> >> Le mar. 12 mars 2024 à 14:17, Petr Krysl <krysl...@gmail.com> a écrit : >> >>> Thanks, that is a helpful confirmation. >>> Would you know if there is any multithreading sparsity pattern >>> computation available anywhere? >>> Is something like this planned for dealii? >>> >>> On Tuesday, March 12, 2024 at 10:39:22 AM UTC-7 bruno.t...@gmail.com >>> wrote: >>> >>>> Hello, >>>> >>>> SparsityPattern is used for deal.II own matrices which do not support >>>> MPI. As far as I can tell, SparsityPattern does not use multithreading and >>>> I don't think adding elements is threadsafe. So you are right. >>>> >>>> Best, >>>> >>>> Bruno >>>> >>>> On Tuesday, March 12, 2024 at 12:58:37 PM UTC-4 krysl...@gmail.com >>>> wrote: >>>> >>>>> It would appear that the sparsity pattern is not (and cannot be) >>>>> computed in parallel. That is my reading of the code. Am I wrong? >>>> >>>> -- >>> The deal.II project is located at http://www.dealii.org/ >>> For mailing list/forum options, see >>> https://groups.google.com/d/forum/dealii?hl=en >>> --- >>> You received this message because you are subscribed to a topic in the >>> Google Groups "deal.II User Group" group. >>> To unsubscribe from this topic, visit >>> https://groups.google.com/d/topic/dealii/hq6L0-qgpbE/unsubscribe. >>> To unsubscribe from this group and all its topics, send an email to >>> dealii+un...@googlegroups.com. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/dealii/d9905f95-ef78-4564-a605-e10c2c19d981n%40googlegroups.com >>> >>> <https://groups.google.com/d/msgid/dealii/d9905f95-ef78-4564-a605-e10c2c19d981n%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> >> -- The deal.II project is located at http://www.dealii.org/ For mailing list/forum options, see https://groups.google.com/d/forum/dealii?hl=en --- You received this message because you are subscribed to the Google Groups "deal.II User Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to dealii+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/dealii/e3a0e7e0-7171-4c00-a2d6-95dc8e690a6an%40googlegroups.com.
