On Jul 28, 2011, at 3:37 PM, Mark F. Adams wrote: > I could not fine PETSC_HAVE_MPI_EXSCAN in the tags file. > > Am I missing something?
Why would it ever be in the tags file until someone uses it? Like I said below you need to use it (where needed) and make sure it gets defined by adding code to MPI.py Barry > > Mark > > On Jul 28, 2011, at 3:31 PM, Barry Smith wrote: > >> >> Ideally code like >> >> #if defined(PETSC_HAVE_MPI_EXSCAN) >> cool C code that uses MPI_EXSCAN >> #else >> less cool C code that uses something else in MPI that is in MPI 1 >> #endif >> >> less ideal but ok code >> >> #if defined(PETSC_HAVE_MPI_EXSCAN) >> cool C code that uses MPI_EXSCAN >> #else >> SETERRQ(..., "Sorry but this code requires MPI_EXSCAN that doesn't exist >> on your machine's version of MPI, install a MPI2 with PETSc to get this >> functionality") >> #endif >> >> >> Then to make sure PETSC_HAVE_MPI_EXSCAN gets defined when it can add a >> test for MPI_Exscan() to bottom of config/BuildSystem/config/packages/MPI.py >> with the other tests for MPI to functions >> >> PETSc only requires MPI 1.1 support so any 2.0 or later stuff used needs >> this kind of protection. >> >> Barry >> >> >> On Jul 28, 2011, at 2:24 PM, Mark F. Adams wrote: >> >>> Dumb question: How do you protect it? >>> Mark >>> >>> On Jul 28, 2011, at 3:05 PM, Barry Smith wrote: >>> >>>> >>>> On Jul 28, 2011, at 11:55 AM, Jose E. Roman wrote: >>>> >>>>> We are getting an undefined reference `MPI_Exscan'. This function is used >>>>> in src/mat/impls/nest/matnest.c. >>>>> If I am not wrong, MPI_Exscan was introduced in MPI-2 but was not >>>>> available in the previous standard. Apparently, the machine where we are >>>>> compiling is very old and has MPI-1 only. >>>>> >>>>> I guess there should be a PETSC_HAVE_MPI_EXSCAN test in configure. >>>> >>>> Correct, whoever used that MPI 2 function in PETSc is obligated to protect >>>> it. >>>> >>>> Barry >>>> >>>> >>>>> >>>>> Jose >>>>> >>>> >>>> >>> >> >> >
