Anyone have any (Windows) experience they can share on setting up a cluster in R (using Rmpi, or other R package) and the snow package, then using parallel? thanks Mark Sale M.D. Senior Vice President, Pharmacometrics Nuventra Inc. 2525 Meridian Parkway, Suite 200 Durham, NC 27713 Phone (919)-973-0383 [email protected]<[email protected]> CONFIDENTIALITY NOTICE The information in this transmittal (including attachments, if any) may be privileged and confidential and is intended only for the recipient(s) listed above. Any review, use, disclosure, distribution or copying of this transmittal, in any form, is prohibited except by or on behalf of the intended recipient(s). If you have received this transmittal in error, please notify me immediately by reply email and destroy all copies of the transmittal. ________________________________ From: Jeff Hammond via discuss <[email protected]> Sent: Saturday, April 27, 2019 9:20 AM To: [email protected] Cc: Jeff Hammond Subject: Re: [mpich-discuss] attribute value of MPI_TAG_UB WARNING: This email originated from outside of the company. Do not click links or open attachments unless you recognize the sender and are expecting the message. On Fri, Apr 26, 2019 at 12:18 PM Wei-keng Liao via discuss <[email protected]<mailto:[email protected]>> wrote: According to MPI 3.1, Section 8.1.2, the attribute value of MPI_TAG_UB attached to MPI_COMM_WORLD can be inquired by function MPI_Comm_get_attr(). It has the same value on all processes of MPI_COMM_WORLD. My first question is should this value be the same across different runs? I would expect it to be the same when running with the same options. It is possible that it will change for different numbers of processes. It is also possible that it changes based upon the network or which back-end is used (eg libfabric provider). A small test program using MPICH 3.3 shows they are not the same across runs and across processes. But when compiled with the latest master branch, they are the same. So, can I assume the answer to my question is YES and MPICH has fixed this in the master branch? My second question is that I notice MPI_TAG_UB is defined as a constant of 0x64400001 (=1681915905) in mpi.h. That value is not the one returned by MPI_Comm_get_attr(), which is 10345120. Is this intended? I don’t think that’s the value but the key used to query it. You need to call get_attr rather than look at this value. The key is meaningless by itself. Jeff I also tested OpenMPI 4.0.0. The inconsistency occurs across different runs, as well as different processes. I can see OpenMPI defines MPI_TAG_UB as an enum type, rather than a constant. Wei-keng _______________________________________________ discuss mailing list [email protected]<mailto:[email protected]> To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss -- Jeff Hammond [email protected]<mailto:[email protected]> http://jeffhammond.github.io/