Is it possible through MPI for a worker to determine: 1. how many MPI processes are running on the local machine 2. within that set its own "local rank"
? For instance, a quad core with 4 processes might be hosting ranks 10, 14, 15, 20, in which case the "local ranks" would be 1,2,3,4. The idea being to use this information so that a program could selectively access different local resources. Simple example: on this 4 worker machine reside telephone directories for Los Angeles, San Diego, San Jose, and Sacramento. Each worker is to open one database and search it when the master sends a request. With the "local rank" number this would be as easy as naming the databases file1, file2, file3, and file4. Without it the 4 processes would have to communicate with each other somehow to sort out which is to use which database. And that could get ugly fast, especially if they don't all start at the same time. Thanks, David Mathog mat...@caltech.edu Manager, Sequence Analysis Facility, Biology Division, Caltech
