Hi,
What you are trying to do should work fine. MPI_File_open() only
requires the amode and file name to match if there are multiple
processes using the same communicator to collectively open the file. In
your case you are using MPI_COMM_SELF, so there is no such requirement.
Have you tried printing the fname string just before MPI_File_open() to
make sure it looks correct on each process? I don't see anything wrong
with your logic, but it would be good to double check the arguments to
MPI_File_open().
-Phil
bin dong wrote:
hi everyone,
I want each process on different servers to write to different
files, so i written following code:
open-test.c
----------------------------------------------------------------------------
... ...
MPI_Comm_rank(MPI_COMM_WORLD, &mynod);
... ...
sprinft(fname, "pvfs2:/mnt/pvfs2/test-%d", mynode)
ret = MPI_File_open(MPI_COMM_SELF,
fname,
MPI_MODE_RDWR|MPI_MODE_CREATE,
MPI_INFO_NULL,
&fh);
ret = MPI_File_write(
fh,
f_buf,
F_BUF_SIZE,
MPI_BYTE,
MPI_STATUS_IGNORE);
... ...
----------------------------------------------------------------------------
compile: mpicc open-test.c -o open-test
run with: mpirun -n 10 ./open-test
when the program is running , i find all ten processes open the
same file(for example, pvfs2:/mnt/pvfs2/test-1),
and write all data to pvfs2:/mnt/pvfs2/test-1.
Then i check the mpi doc of mpi_file_open, it says that:
.....all processes must provide the same value for _amode,_ and
all processes must provide
filenames that reference the same file and which are textually identical.
* So i think even though i pass different names to MPI_File_open in
different processes, it will open the same file, *
* and then the following MPI_File_write will write the all data to
the same file.*
*
*
Can someone tell me whether what i think is right or not?
If i am right, how can I open different files in different process?
Thanks in advance!
Din Dong
------------------------------------------------------------------------
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