On Thu, Jan 14, 2016 at 3:05 PM, George Bosilca <bosi...@icl.utk.edu> wrote:
> > On Jan 13, 2016, at 19:57 , Jim Edwards <jedwa...@ucar.edu> wrote: > > George and all. > > Back to OpenMPI, now the question is : > > “Is OpenMPI going to be updated (and when) in order to support an > intuitive and user friendly feature, that is currently explicitly > prohibited by the MPI 3.1 standard, but that might be part of the MPI-4 > standard and that we already know is not backward compatible (*) ? > > > If the MPI Forum agrees to amend the standard to allow this [currently > forbidden] behavior, we will be bound to adapt. Meanwhile, I would assume > that with regard to this particular question the MPICH implementation is > far too user-friendly and only loosely standard compliant. > The MPI standard does not require implementations to catch ANY invalid usage errors, so MPICH compliance is in no way affected by allowing invalid usage. The error in question is completely innocuous and there is no value whatsoever to crashing a user application over it. If you want to hop on the standard-compliance soapbox, let's start with MPI-2 features like MPI_THREAD_MULTIPLE and RMA ;-) > (*) fwiw, mpich already “implements" this, so backward incompatibility > would only affect tools currently working with OpenMPI but not with mpich." > > i am a pragmatic guy, so i'd rather go for it, but here is what i am gonna > do : > > unless George vetoes that, i will add this topic to the weekly call > agenda, and wait for the community to make a decision > (e.g. go / no go, and milestone if needed 1.10 series ? 2.0 ? 2.1 ? master > only ?) > > > A pragmatic user will certainly appreciate in all circumstances to type > less characters (MPI_BYTE) instead of MPI_DATATYPE_NULL when used in > combination with a statically known count of 0. > > What is the type of NULL and nullptr? Both because of static analysis and inferring MPI datatypes from pointer types (as done in C++ codes), I'm not sure it's a good idea to say that null buffers have a well-defined MPI type. Jeff > Cheers, > George. > > > > Cheers, > > Gilles > > > > _______________________________________________ > users mailing list > us...@open-mpi.org > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users > Link to this post: > http://www.open-mpi.org/community/lists/users/2016/01/28277.php > -- Jeff Hammond jeff.scie...@gmail.com http://jeffhammond.github.io/
