[mvapich-discuss] Downloading mvapich2-gdr versions and compatibility between versions

[Subramoni, Hari]

Hello.

I do not understand the question very clearly. For instance, what do you mean by installing a GNU version of MVAPICH2-GDR and using it with Intel/PGI compilers? Do you mean to say that you have an application that does something like this

CC=pgcc
MPICC=mpicc

CC <some_c_file.c>
MPICC <some_mpi_c_file.c>

Link all of them together with CC as the linker?

We have never tried such a combination internally. In principle, it may work, however you could hit weird issues due to minor differences between how compilers perform optimizations.

Further, it is not just compatibility, the choice of compilers can also affect the performance of end applications and the optimization level that gets used.

Thx,
Hari.

From: mvapich-discuss-bounces at cse.ohio-state.edu On Behalf Of Raghu Reddy
Sent: Wednesday, April 11, 2018 8:45 AM
To: mvapich-discuss at cse.ohio-state.edu <mvapich-discuss at mailman.cse.ohio-state.edu>
Subject: [mvapich-discuss] Downloading mvapich2-gdr versions and compatibility between versions

Dear mvapich2 team,

When trying to download mvapich2-gdr, there is a table of options available to download.  For example when I look at the row headings:

GNU/4.8.5 and PGI (for various scheduler combinations).

Previously whenever we needed an Intel version we requested it and that was provided very promptly!   Thank you, and very much appreciated!  :)

One question I have is, both PGI and Intel are compatible with GNU as long as FORTRAN 90 modules are not involved.  So as long as we're not using "module use mpi" is it fair to say we could just install the GNU version and use it with any of these three compilers (GNU, Intel, and PGI)?

Is it fair to say separate versions are provided primarily because of incompatibility introduced used by:


-          Fortran 90 (primarily by "module use mpi"?)

-          C++, which may not be compatible for a similar reason

As long as our codes are not using C++ MPI constructs and Fortran does not use "module use mpi"  is there any reason to explicitly request an Intel build?

Thanks!
Raghu

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