[mpich-discuss] Fortran 08 tests with 'use mpi'

Raffenetti, Ken raffenet at anl.gov
Thu Jan 13 06:10:42 CST 2022


Thanks for the update. I suspect you have come across a bug in the binding layer. I'll take a closer look and let you know what I find.


On 1/12/22, 5:19 AM, "Gregor Corbin" <g.corbin at fz-juelich.de> wrote:


        while updating the F08 tests with this bugfix, I may have found
          another bug inside the 'use mpi_f08' wrappers.
        The fix removes (superficially) the error in irsendf08, but I
          still get the same error in pssendf08. This has to do with the
          array of indices returned by MPI_Testsome: With the 'use mpi_f08'
          wrappers, the indices in this array are 0-indexed although they
          should start from 1 according to the Standard (they do start from
          1 with the 'use mpi' and 'mpif.h' functions). I have attached a
          minimal working example to confirm this.
        Indeed, the function mpi_testsome_ (in
          src/binding/fortran/mpif_h/fortran_binding.c) converts the

              for (int i = 0; i < (*outcount); i++) {
                    array_of_indices[i] += 1;

        The subroutine MPI_Testsome_f08 (in
          src/binding/fortran/use_mpi_f08/wrappers_f/f08ts.f90) does no such

        The bug is also in MPI_Testany (and potentially other functions I
          did not test yet).

        However, without detailed knowledge about internals of MPICH I
          might not be the best person to fix the issue.

        On 11.01.22 22:52, Raffenetti, Ken


    I believe these are test bugs. A fix for the f77 versions was added previously in https://github.com/pmodels/mpich/pull/3962/commits/69b02eaabcdb0008f3879372629cfe92f98e8d56, though it does not cover the prsendf test. Perhaps you could add a commit to your branch to fix these tests in a similar way.


    On 1/11/22, 2:30 AM, "Gregor Corbin" <g.corbin at fz-juelich.de> <mailto:g.corbin at fz-juelich.de> wrote:

            Updating the F08 tests to 'use mpi_f08' was mostly
              straightforward. However, i ran into problems with three of the
              tests: irsendf08.f90, pssendf08.f90 and prsendf08.f90.
            With my modified irsendf08 (attached) for example, the test
              produces these error messages:  

               Nonnull request in irsend and irecv
                 [           0 ] Unexpected source:           0  in irsend and
                 [           0 ] Unexpected tag:           0  in irsend and
                 [           0 ] Unexpected count:           0  in irsend and
                Invalid data   0.0 at    1 of  666 in irsend and irecv
                Invalid data   0.0 at    2 of  666 in irsend and irecv
              Invalid data   0.0 at  666 of  666 in irsend and irecv
                Found          669  errors

            That is, the last message from process 1 to 0 is not received
            correctly. When I replace the call to MPI_Waitany with Waitall or
            Wait there are not errors.
            Is there maybe a problem with Waitany or did I just do something

            On 07.01.22 17:59, Raffenetti, Ken

              We would consider a patch, yes. First, you would need to sign and return the contributors agreement. https://www.mpich.org/documentation/contributor-docs/

        As for whether or not automatic conversion is practical, I think if we structured the tests such that the types needing conversion were easily identifiable, then it could be done. It would require some churn of the existing tests. It may also complicate the addition of new, as the author would need to adhere to guidelines that may not be obvious without prior knowledge.

        I gave myself a task to support automatic conversion of the tests the `use mpi_f08`, but it is not very high priority at the moment.


        On 1/7/22, 3:10 AM, "Gregor Corbin via discuss" <discuss at mpich.org> <mailto:discuss at mpich.org> <mailto:discuss at mpich.org> <mailto:discuss at mpich.org> wrote:

            Hi MPICH,

            I noticed that some of the tests in test/mpi/f08 still work with 'use 
            mpi' instead of  'use mpi_f08', mostly in the pt2pt folder. These seem 
            to be copies of the tests in f90 which in turn have been generated by 

            Shouldn't these tests be converted to 'use mpi_f08'? If so, would you be 
            interested in a PR that fixes this? I would need to do this anyway.

            Kind regards,

            Gregor Corbin

            PS.: The interfaces for 'use mpi' and 'use mpi_f08' are probably too 
            different for an automatic conversion to be practical (how to change all 
            the integers to type(mpi_xxx) for example?).

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