Thanks a lot, Jeff! What you said all make perfect sense.
One concern my client has, is that whether using LAM universe
and published names to connect two MPI processes is
portable or not to MPICH. Some of their clusters only provide
MPICH but not LAM MPI (sad but true).
I know this is not a MPICH user group, but is the concept of a universe
a standard MPI feature or LAM specific? Is the design you provided
portable to all MPI implementations? If not, can you provide the
necessary modifications please?
Thanks again,
-Lei
Jeffrey Squyres wrote:
>>Is there a way to start a LAM daemon network among a list of IPs
>>using MPI_Init(int *argc, char ***argv) from a sequential program like
>>a.out?
>>
>>
>
>Yes and no. LAM *must* have a universe before any MPI application will
>run. So if you run a.out without a LAM universe, you'll get an error
>message.
>
>Hence, you must lamboot before you run any MPI application under LAM.
>You can do this before you run matlab, or from your mex script (e.g.,
>fork/exec a lamboot). Once you have a lamboot, then you can call
>MPI_Init and start doing things like MPI_Comm_spawn. In addition, the
>design that I gave below (I think you cut-n-pasted that from a message
>from the LAM mailing list archives, right?) assumes that there is a LAM
>universe running because it uses published names, etc. which only exist
>if a LAM universe exists.
>
>
>
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