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From: George Bosilca (bosilca_at_[hidden])
Date: 2006-07-11 15:30:56


Yvan,

Shame on me for bringing this bug back into the 1.1. Until we release
the 1.1.1 please use the nightly build or the beta from our web site.
Starting with the revision 10710 this bug was removed. Forever I hope :)

   Thanks,
     george.

On Jul 10, 2006, at 5:27 PM, Yvan Fournier wrote:

> Hello,
>
> I just retried replicating the datatype bug on a SUSE Linux 10.1
> system
> (on a 32-bit Pentium-M system). Actually, I even get a segmentation
> fault at some point. I attach the logfile for the test case
> compiled in debug mode, run once directly, the again with valgrind,
> as well as my ompi_info output.
>
> I have also encountered the bug on the "parent" case (similar, but
> more complex) on my work machine (dual Xeon under Debian Sarge),
> but I'll check this simpler test on it just in case.
>
> Best regards,
>
> Yvan Fournier
>
>
>
> On Sun, 2006-07-09 at 12:00 -0400, users-request_at_[hidden] wrote:
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>> Today's Topics:
>>
>> 1. Re: Datatype bug regression from Open MPI 1.0.2 to Open MPI
>> 1.1 (George Bosilca)
>>
>>
>> ---------------------------------------------------------------------
>> -
>>
>> Message: 1
>> Date: Sat, 8 Jul 2006 13:47:05 -0400 (Eastern Daylight Time)
>> From: George Bosilca <bosilca_at_[hidden]>
>> Subject: Re: [OMPI users] Datatype bug regression from Open MPI 1.0.2
>> to Open MPI 1.1
>> To: Open MPI Users <users_at_[hidden]>
>> Message-ID: <Pine.WNT.4.64.0607081344080.2944_at_bosilca>
>> Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
>>
>> Yvan,
>>
>> I'm unable to replicate this one with the latest Open MPI trunk
>> version.
>> As there is no difference between the trunk and the latest 1.1
>> version on
>> the datatype, I think the bug cannot be reproduced using the 1.1
>> either. I
>> compiled the test twice once using the indexed datatype and once
>> without
>> and the output is exactly the same. I run it on my Apple G5
>> desktop as
>> well as on a cluster of AMD 64, over shared memory and TCP. Can
>> you please
>> recheck that your error is comming from the type indexed please.
>>
>> Thanks,
>> george.
>>
>>
>> On Sat, 1 Jul 2006, Yvan Fournier wrote:
>>
>>> Hello,
>>>
>>> I had encountered a bug in Open MPI 1.0.1 using indexed datatypes
>>> with MPI_Recv (which seems to be of the "off by one" sort), which
>>> was corrected in Open MPI 1.0.2.
>>>
>>> It seems to have resurfaced in Open MPI 1.1 (I encountered it using
>>> different data and did not recognize it immediately, but it seems
>>> it can reproduced using the same simplified test I had sent
>>> the first time, which I re-attach here just in case).
>>>
>>> Here is a summary of the case:
>>>
>>> ------------------
>>>
>>> Each processor reads a file ("data_p0" or "data_p1") giving a
>>> list of
>>> global element ids. Some elements (vertices from a partitionned
>>> mesh)
>>> may belong to both processors, so their id's may appear on both
>>> processors: we have 7178 global vertices, 3654 and 3688 of them
>>> being
>>> known by ranks 0 and 1 respectively.
>>>
>>> In this simplified version, we assign coordinates {x, y, z} to each
>>> vertex equal to it's global id number for rank 1, and the
>>> negative of
>>> that for rank 0 (assigning the same values to x, y, and z). After
>>> finishing the "ordered gather", rank 0 prints the global id and
>>> coordinates of each vertex.
>>>
>>> lines should print (for example) as:
>>> 6456 ; 6455.00000 6455.00000 6456.00000
>>> 6457 ; -6457.00000 -6457.00000 -6457.00000
>>> depending on whether a vertex belongs only to rank 0 (negative
>>> coordinates) or belongs to rank 1 (positive coordinates).
>>>
>>> With the OMPI 1.0.1 bug (observed on Suse Linux 10.0 with gcc 4.0
>>> and on
>>> Debian sarge with gcc 3.4), we have for example for the last
>>> vertices:
>>> 7176 ; 7175.00000 7175.00000 7176.00000
>>> 7177 ; 7176.00000 7176.00000 7177.00000
>>> seeming to indicate an "off by one" type bug in datatype handling
>>>
>>> Not using an indexed datatype (i.e. not defining
>>> USE_INDEXED_DATATYPE
>>> in the gather_test.c file), the bug dissapears.
>>>
>>> ------------------
>>>
>>> Best regards,
>>>
>>> Yvan Fournier
>>>
>>>
>>
>> "We must accept finite disappointment, but we must never lose
>> infinite
>> hope."
>> Martin Luther King
>>
>>
>>
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>>
>> <ompi_info>
>> <logfile.gz>
>> <logfile_valgrind.gz>
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