Yes, but it is a little more tricky than calling MPI_Bcast.

The prototype of MPI_Bcast as defined by the MPI standard is:
 
int MPI_Bcast(void* buffer, int count, MPI_Datatype datatype, int root,
             MPI_Comm comm)

This clearly prevents you from using a count larger than MAX_INT. However, you can build a datatype, by composing several types with counts under 1G and then use this datatype to do the bcast.

  George.

On Apr 12, 2013, at 00:11 , William Au <au_wai_chung@hotmail.com> wrote:

Hi,

I am using openmpi 1.6 and when I tried to send a large array through MPI_BCAST
in fortran. The number of count is larger than 3 billions. Although I compiled openmpi and
my code with the option to declare my fortran integer as 64 bit long in linux. I found out
that fortran pbcast_f.c will cast my *count to integer to call the c code MPI_Bcast

  *ierr = OMPI_INT_2_FINT(MPI_Bcast(OMPI_F2C_BOTTOM(buffer),
                                            OMPI_FINT_2_INT(*count),

So my question is, is it possible to bcast more than MAX_INT count of data_type in
openmpi?

Thanks.

Regards,

William
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