Dorian,

You are right, the datatype generated using the block_index function is a legal data-type. We wrongly determined some overlapping regions in the description [which is illegal based on the MPI standard]. The detection of such overlapping regions being a very expensive process if we don't want any false positives (such as your datatype), I prefer to remove it completely.

To keep it short I just committed a patch (r20120) in the trunk, and I'll take care to move it in the 1.3 and the 1.2.9.

  Thanks for your help,
    george.

On Dec 10, 2008, at 18:07 , doriankrause wrote:

Hi List,

I have a MPI program which uses one sided communication with derived
datatypes (MPI_Type_create_indexed_block). I developed the code with
MPICH2 and unfortunately didn't thought about trying it out with
OpenMPI. Now that I'm "porting" the Application to OpenMPI I'm facing
some problems. On the most machines I get an SIGSEGV in MPI_Win_fence,
sometimes an invalid datatype shows up. I ran the program in Valgrind
and didn't get anything valuable. Since I can't see a reason for this
problem (at least if I understand the standard correctly), I wrote the
attached testprogram.

Here are my experiences:

* If I compile without ONESIDED defined, everything works and V1 and V2
give the same results
* If I compile with ONESIDED and V2 defined (MPI_Type_contiguous) it works. * ONESIDED + V1 + O2: No errors but obviously nothing is send? (Am I in
assuming that V1+O2 and V2 should be equivalent?)
* ONESIDED + V1 + O1:
[m02:03115] *** An error occurred in MPI_Put
[m02:03115] *** on win
[m02:03115] *** MPI_ERR_TYPE: invalid datatype
[m02:03115] *** MPI_ERRORS_ARE_FATAL (goodbye)

I didn't get a segfault as in the "real life example" but if ompitest.cc
is correct it means that OpenMPI is buggy when it comes to onesided
communication and (some) derived datatypes, so that it is probably not
of problem in my code.

I'm using OpenMPI-1.2.8 with the newest gcc 4.3.2 but the same behaviour
can be be seen with gcc-3.3.1 and intel 10.1.

Please correct me if ompitest.cc contains errors. Otherwise I would be
glad to hear how I should report these problems to the develepors (if
they don't read this).

Thanks + best regards

Dorian




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