[mpiwg-tools] proposed text

Sat Nov 22 16:04:19 CST 2014

Hi Jeff, 

Thanks for the feedback!

I made all the changes and agree with them for the most part (new document
attached). Comments inlined:

>
>p9:40-p10:1 reads:
>
>I'd change it to be:
>
>MPI implementations behave as if they have an internal character array
>that is copied to the output character array supplied by the user.  Such
>output strings are defined to be equivalent if their notional source
>internal character arrays are identical (up to and including the null
>terminator), even if the output string is truncated due to a small n
>length parameter.

"due to a small n length parameter." For some reason the word "small"
seems odd to me here. Do we want it to be more formal, and specify that
it's the input value of n that causes the truncation and that n could be
different on different processes?

>
>Nit picks
>=========
>
>1. p7:23-26 reads:
>
>I'd change the parenthetical to:
>
>Variables and categories across connected processes with equivalent names
>are required to have the same meaning (***please see the definition of
>"equivalent" as related to strings in*** Section 14.3.3).

I'm assuming you didn't mean the *** literally but to draw attention to
the change. Also, I'm not sure if Bronis will chime in to correct our
punctuation here, but I believe because the parenthetical text forms a
complete sentence we would need to treat it as such, i.e. With proper
capitalization and punctuation. However, I don't know for sure, so if
someone does, please speak up!

Thanks for the rest of your comments and the example of why we don't want
to include enumerations.

Kathryn

>
>3. p7:27-28 says:
>
>For example, variables describing the number of packets sent on
>heterogeneous network devices should have different names to reflect
>their potentially different meanings.
>
>I'd change it to be:
>
>For example, variables describing the number of packets sent on
>***different types of*** network devices should have different names to
>reflect their potentially different meanings.
>
>I know that "heterogeneous" means "different types", but that word
>carries a different connotation here, IMHO -- "heterogeneity" is somewhat
>of a loaded word in HPC environments (e.g., it's usually applied to
>processors and brings up a slightly confusing context here -- so let's
>just avoid it).
>
>Enumerations
>============
>
>Yes, enumerated values must *not* be defined as equivalent.
>
>I have a concrete example why they should not be equivalent:
>
>- Remember that I want to use enumerated values to contain information
>about the underlying network
>- The network interface used by MPI processes on server A has network
>address "A.B.C.D", but the NI used by MPI processes on server B has
>address "W.X.Y.Z".
>
>
>
>
>
>
>On Nov 21, 2014, at 11:48 AM, Kathryn Mohror <kathryn at llnl.gov> wrote:
>
>> The updated version is attached. Please comment if you have a chance so
>>we
>> can get this done by Monday.
>> 
>> Thank you!
>> Kathryn
>> _________________________________________________________________
>> Kathryn Mohror, kathryn at llnl.gov, http://scalability.llnl.gov/
>> Scalability Team @ Lawrence Livermore National Laboratory, Livermore,
>>CA,
>> USA
>> 
>> 
>> 
>> 
>> 
>> 
>> On 11/21/14, 7:09 AM, "Kathryn Mohror" <kathryn at llnl.gov> wrote:
>> 
>>> Thanks for the feedback Michael and Marc-Andre! I'll make the changes
>>> later this morning and send them out.
>>> 
>>> Kathryn
>>> _________________________________________________________________
>>> Kathryn Mohror, kathryn at llnl.gov, http://scalability.llnl.gov/
>>> Scalability Team @ Lawrence Livermore National Laboratory, Livermore,
>>>CA,
>>> USA
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> On 11/21/14, 2:38 AM, "Marc-Andre Hermanns" <m.a.hermanns at grs-sim.de>
>>> wrote:
>>> 
>>>> Hi all,
>>>> 
>>>>> I have an issue with the new text. I'm not sure if I'm missing a
>>>>> point, but for me the equivalence text is redundant. I fail to see a
>>>>> difference between (page 9, lines 43ff)
>>>>> 
>>>>> Strings are equivalent if the MPI implementation behaves as if it has
>>>>> an identical character array in each MPI process for the string in
>>>>> question across connected processes. The contents of the returned
>>>>> string will be identical to that of the internal character array, but
>>>>> possibly truncated at any process that supplies an n value to the
>>>>> query routine that is smaller than the length of the internal
>>>>> character array.
>>>> 
>>>> I also think this covers all cases.
>>>> 
>>>> a) a string is equivalent to its internal "source" if it behaves as if
>>>> being copies from it up the the given length.
>>>> 
>>>> b) two strings are equivalent when they behave as if the originate
>>>>from
>>>> an identical source.
>>>> 
>>>>> and (page 10, lines 1ff)
>>>>> 
>>>>> Two strings are equivalent if the internal character array for each
>>>>> MPI process is identical by a character-by-character comparison, and
>>>>> in the output buffer, any arbitrary combination of length arguments
>>>>> result in the same string-prefix up to the smaller of the two
>>>>>lengths.
>>>>> 
>>>>> So I'll probably would remove the second part (although I still like
>>>>> the wording).
>>>>> 
>>>>> Any opinions on that?
>>>> 
>>>> I talked to Michael on this, and I also think the second part can be
>>>> omitted.
>>>> 
>>>>> The rest looks fine so far.
>>>> 
>>>> dito.
>>>> 
>>>> Cheers,
>>>> Marc-Andre
>>>> -- 
>>>> Marc-Andre Hermanns
>>>> Jülich Aachen Research Alliance,
>>>> High Performance Computing (JARA-HPC)
>>>> German Research School for Simulation Sciences GmbH
>>>> 
>>>> Schinkelstrasse 2
>>>> 52062 Aachen
>>>> Germany
>>>> 
>>>> Phone: +49 241 80 99753
>>>> Fax: +49 241 80 6 99753
>>>> www.grs-sim.de/parallel
>>>> email: m.a.hermanns at grs-sim.de
>>>> 
>>> 
>>> 
>>> _______________________________________________
>>> mpiwg-tools mailing list
>>> mpiwg-tools at lists.mpi-forum.org
>>> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-tools
>> 
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>
>
>-- 
>Jeff Squyres
>jsquyres at cisco.com
>For corporate legal information go to:
>http://www.cisco.com/web/about/doing_business/legal/cri/
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