[mpich-discuss] Account Request / Bug report MPI_Type_create_f90_real

[Dave Goodell]

A note (mainly for other MPICH devs):

I have created a trac account for Harald and sent him his account information off-list.

-Dave

On Dec 19, 2012, at 9:23 AM CST, Harald Klimach wrote:

> Hi there,
> 
> I installed MPICH2 3.0rc1 using GCC 4.7.2 and found a problem with MPI_Type_create_f90_real.
> It is very similar to the problem I reported in OpenMPI under: https://svn.open-mpi.org/trac/ompi/ticket/3432
> 
> Running the following program:
> 
> program test_mpi
> use mpi
> implicit none
> 
> integer, parameter :: rk_prec = 15
> integer, parameter :: rk = selected_real_kind(rk_prec)
> 
> integer :: rk_mpi
> integer :: iError
> real(kind=rk) :: a_real
> real(kind=rk) :: res
> 
> call MPI_Init(iError)
> call mpi_type_create_f90_real(rk_prec, MPI_UNDEFINED, rk_mpi, iError)
> write(*,*) 'MPI_REAL8:', MPI_REAL8
> write(*,*) 'MPI_DOUBLE_PRECISION:', MPI_DOUBLE_PRECISION
> write(*,*) 'type_create_f90_real:', rk_mpi
> a_real = 1.0
> call MPI_Reduce(a_real, res, 1, rk_mpi, MPI_MIN, 0, MPI_COMM_WORLD, iError)
> call MPI_Finalize(iError)
> 
> end program test_mpi
> 
> 
> Results in the following output and error:
> 
> MPI_REAL8:  1275070505
> MPI_DOUBLE_PRECISION:  1275070495
> type_create_f90_real: -1946157049
> Fatal error in PMPI_Reduce: Invalid MPI_Op, error stack:
> PMPI_Reduce(1217)........: MPI_Reduce(sbuf=0x7fff43637108, rbuf=0x7fff436370f8, count=1, dtype=USER<f90_real>, MPI_MIN, root=0, MPI_COMM_WORLD) failed
> MPIR_MINF_check_dtype(71): MPI_Op MPI_MIN operation not defined for this datatype
> 
> 
> Further the quadruple precision data type is not properly supported:
> MPI_Type_create_f90_real will complain about wrong exponent, regardless of its value,
> while MPI_REAL16 is available and the Reduction operation does not complain, it produces
> wrong results. Again there is a similar problem with OpenMPI, as reported under:
> https://svn.open-mpi.org/trac/ompi/ticket/3433
> 
> Thanks a lot,
> Harald Klimach
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