[MPICH] Specifying machinefile within MPI_Comm_spawn command

[Rajesh Sudarsan]

Thanks Rajeev.  I followed the steps as directed and it worked.

Regards,
Rajesh


Rajeev Thakur wrote:
> You need to pass an MPI_Info object with the key "host" and value set to the
> hostname. I believe that this is one per process. So if you need to spawn
> two processes, you need to call MPI_Comm_spawn_multiple, with count=2,
> array_of_commands={worker,worker}, array_of_maxprocs={1,1},
> array_of_info={"host""debug7","host""debug8"; ie 2 info objects with the 2
> hostnames.
>
> Let us know if that doesn't work.
>
> Rajeev 
>  
>
>   
>> -----Original Message-----
>> From: owner-mpich-discuss at mcs.anl.gov 
>> [mailto:owner-mpich-discuss at mcs.anl.gov] On Behalf Of Rajesh Sudarsan
>> Sent: Thursday, February 16, 2006 10:40 AM
>> To: mpich-discuss at mcs.anl.gov
>> Subject: [MPICH] Specifying machinefile within MPI_Comm_spawn command
>>
>> Hi,
>> I am trying out a simple example using MPI_Comm_spawn command 
>> in mpich2. 
>> The command works fine and it spawns new processes without any
>> error. But I am not able to specify on which processor node 
>> to spawn the 
>> process. The only argument where I thought I could enter the node
>> information was MPI_Info argument in the MPI_Comm_spawn command. But 
>> still the spawn command starts the new processes on arbitrary nodes.
>>
>> I know that in the case of LAM/MPI, the node specification for spawn 
>> process is given as a "appshcema" file using MPI_Info 
>> argument. But the
>> same technique does not seem to work in mpich2.
>>
>> I read the earlier posts in Jan 2006 on this similar issue, but the 
>> solution posted suggested to use some flags with the mpiexec 
>> command.  
>> The code that I am using,  spawns new processes in every iteration. I 
>> believe setting the flags will be effective only the first 
>> time when the 
>> process is spawned.
>>
>> Has any one else faced a similar problem?
>>
>> My current schema file for the spawn command looks like this.
>>
>> debug7 -np 1 -wd /nfs/storage1/users/sudarsar/  worker
>> debug8 -np 1  -wd /nfs/storage1/users/sudarsar/  worker
>>
>> debug7 and debug8 are the nodes where I want to spawn new processes 
>> using the spawn command.  "np" specifies the number of processes to be
>> spawned on each node. "wd" specifies the working directory. 
>> And the last 
>> argument gives the executable name.
>>
>> I would really appreciate any kind of help.
>>
>> Regards,
>> Rajesh
>>
>> <http://groups.google.com/group/comp.parallel.mpi/browse_threa
>> d/thread/3a3d738528ee2147?hl=en#> 
>>
>>
>>     
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