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From: Ali Eghlima (Ali_Eghlima_at_[hidden])
Date: 2006-03-27 09:27:56

  Thanks Ralph and Jean.

Is there any chances that this feature be added to the next release of
mpiexec (mpirun).

Thanks again



Ralph Castain <rhc_at_[hidden]>
Sent by: users-bounces_at_[hidden]
03/27/2006 08:44 AM
Please respond to
rhc_at_[hidden]; Please respond to
Open MPI Users <users_at_[hidden]>

Open MPI Users <users_at_[hidden]>

Re: [OMPI users] How to establish communication between two separate COM

Actually, in a not-too-distant future release, there will be an option to
mpirun called "--connect" that will allow you to specify that this job is
to be connected to a specified earlier job. The run-time environment will
then spawn the new job and exchange all required communication information
between the two jobs for you. You could therefore accomplish your desired
operation by:

> nohup mpirun --np xx app1
(system returns job number to you)
> mpirun --np yy --connect job1 app2
(system starts app2 and connects it to job1)

Should be a little more transparent. No specific coding for making the
connection would be required in your application itself.


Jean Latour wrote:

It seems to me there is only one way to create a communication between
two MPI_COMM_WORLD : use MPI_Open_Port with a specific
IP + port address, and then MPI_comm_connect / MPI_comm_accept.

In order to ease the port number communication, the use of
/ MPI_lookup_name is also possible with the constraint that the "publish"
must be done before the "lookup", and this involves some synchronization
between the processes anyway.

Simple examples can be found in the handbook on MPI : "Using MPI-2"
by William Gropp et al.

Best Regards,

Ali Eghlima wrote:


I have read MPI-2 documents as well as FAQ. I am confused as the best way
to establish communication
between two MPI_COMM_WORLD which has been created by two mpiexec calls on
the same node.

mpiexec -conf config1
     This start 20 processes on 7 nodes

mpiexec -conf config2
      This start 18 processes on 5 nodes

I do appreciate any comments or pointer to a document or example.





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