On 09/09/2014 01:19 PM, Venkat Vishwanath wrote:

There is a maximum # of communicators one can create. How can I query this limit for MPICH? Is there a standard way to query this limit across MPI implementations?

Huh. It would appear not: Cray uses an environment variable: http://docs.cray.com/books/S-2310-50/html-S-2310-50/z1026396842smg.html Intel asserts it's ~16k: - https://software.intel.com/en-us/forums/topic/279324 MPICH limit used to be 8189: - http://www.mcs.anl.gov/papers/P1621A.pdf I guess the way to query is "create until it fails" ? ==rob -- Rob Latham Mathematics and Computer Science Division Argonne National Lab, IL USA