On Wed, 21 May 2003, choy hau yan wrote:
> is that any limit for mpi_bcast?
> I found that when sending more than some limit of
> number, the result does not same.
> is that the buffer is full already ?
> Hope that anyone can answer my question. thanks.
There are no LAM-specific limits for mpi_bcast. LAM does have to malloc a
small amount of memory in mpi_bcast, but this should only be a problem if
you are trying to send a message close to the size of the virtual memory
in your machine.
I would guess that your application is experiencing some "memory badness"
- your application is reading or writing memory that you don't own. I
would try running your application under a memory checking debugger (such
as solaris's bcheck or Valgrind on linux.
Also note that MPI will *not* modify parts of the buffer that were used in
the bcast. So if you pass in a buffer of 100 bytes and only broadcast 1
byte, then the remaining 99 won't be touched.
Hope this helps,
Brian
--
Brian Barrett
LAM/MPI developer and all around nice guy
Have a LAM/MPI day: http://www.lam-mpi.org/
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