[Mpi3-tools] Type sizes in MPI_T

William Gropp wgropp at illinois.edu
Fri Jun 24 01:52:11 CDT 2011


Possible refers to the values (and that there are other choices,  
including the derived types); sizeof may be used for the basic types  
instead of MPI_Type_size.


On Jun 23, 2011, at 9:39 PM, Martin Schulz wrote:

> Hi all,
> Christof has been going over the MPI_T document (thanks!) and
> found a few issues - I will fix those and post a new draft tonight.
> One issue, however, we were not sure about: since we are
> not allowing any MPI calls between MPI_T_Init_thread and
> MPI_Init (only MPI_T calls), we also cannot call any MPI
> Type related calls, such as MPI_Type_size or calls for
> naming or setting attributes. The latter we can probably
> get away with not having until MPI_Init, but we were not sure
> on MPI_Type_size.
> Since we are only using basic types, can we assume that they
> always represent their corresponding C types as specified in
> Section 3.2.2? I always assumed this, but looking closer, we
> were not 100% certain on how to interpret the following sentence
> in that section:
> Possible values for this argument for C and the corresponding
> C types are listed in Table 3.2.
> Does the possible only refer to the values or also to the
> corresponding C types? If it is the former, then we can get
> the size simply by calling sizeof(...) and  this is not an
> issue.
> Thanks,
> Martin
> ________________________________________________________________________
> Martin Schulz, schulzm at llnl.gov, http://people.llnl.gov/schulzm
> CASC @ Lawrence Livermore National Laboratory, Livermore, USA
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William Gropp
Director, Parallel Computing Institute
Deputy Director for Research
Institute for Advanced Computing Applications and Technologies
Paul and Cynthia Saylor Professor of Computer Science
University of Illinois Urbana-Champaign

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