[mpiwg-tools] proposed text

Thu Nov 20 08:00:13 CST 2014

Hi Kathryn,

you used the <foo>=MPI_T version right?

What do you think about this:

---o---o---o---o---
14.3.3

...
Several query functions of the MPI_T interface return information
encoded in C strings. A user of these query routines can influence the
concrete length of the output through INOUT length parameters to these
calls, potentially resulting in a truncated string. As the INOUT length
parameters are allowed to vary across different invocations of a call,
two strings returned by subsequent calls with varying length arguments
but otherwise identical arguments may not be identical as defined by the
result of the strcmp family of calls. However, they have to be
equivalent. In the scope of the MPI_T interface, two strings are
regarded equivalent, if any arbitrary combination of length arguments
result in the same string-prefix up to the smaller of the two lengths.

---o---o---o---o---

This goes back to Michael's initial idea of regarding "pairs of
strings". Again, some of my prose may be convoluted and I am open to any
revision. ;-)

And then we don't need the "MPI_T" string at all, as the equivalence is
all the "specialness" we want from our strings. Thus, we can then (at
those 6 places) just state: "parameters foo and bar have to be
equivalent as described in 14.3.3."

What do you think?

Cheers,
Marc-Andre

On 19.11.14 21:53, Kathryn Mohror wrote:
> Okay, here's a draft attempting to capture what Jeff and Martin were
> getting at in the last meeting. I made changes to 14.3.3 and to the text
> of the get_info routines for name and desc parameters, and to the last
> paragraph for the routine description.
> 
> Have at it!
> 
> Kathryn
> _________________________________________________________________
> Kathryn Mohror, kathryn at llnl.gov, http://scalability.llnl.gov/
> Scalability Team @ Lawrence Livermore National Laboratory, Livermore, CA,
> USA
> 
> 
> 
> 
> 
> 
> On 11/19/14, 12:17 PM, "Kathryn Mohror" <kathryn at llnl.gov> wrote:
> 
>> Thanks Bronis. I like the suggestion of equivalence instead of identical.
>>
>> Kathryn
>>
>>
>>>
>>> "quasi-identical" and its variants sounds horrible to
>>> me without even looking at the context. What do you
>>> want to require? "functionally equivalent"? I think
>>> you need to move away from the word "identical" and
>>> think instead in terms of "equivalence"...
>>>
>>> On Wed, 19 Nov 2014, Marc-Andre Hermanns wrote:
>>>
>>>> Hi Kathryn,
>>>>
>>>>>> I think we don't have to search&replace the word string for <foo>
>>>>>> string
>>>>>> throughout the chapter. I think we only need to define <foo> string
>>>>>> in
>>>>>> 14.3.3 and then state for the 6 parameters so far that those are foo
>>>>>> strings.
>>>>>
>>>>> Okay, I'll work on it and try to integrate it cleanly.
>>>>>>
>>>>>> By and large <foo> strings are just like other C string. We just have
>>>>>> additional requirements to what "identical" means. That is why I came
>>>>>> up
>>>>>> with the name: "quasi-identical", because they are not identical in
>>>>>> the
>>>>>> normal C string sense (str*cmp). As "quasi-identical" is a new kind
>>>>>> of
>>>>>> string, that probably no-one heard in a different context, so has no
>>>>>> preoccupation on what it could mean, a reader should go: "What's
>>>>>> that?"
>>>>>> and refer to Section 14.3.3.
>>>>>>
>>>>>> What's the groups take on the name "quasi-identical"?
>>>>>
>>>>> I'm not totally sold on 'quasi-identical' but possibly because I don't
>>>>> use
>>>>> the prefix 'quasi' very often. Also, I almost think that it takes away
>>>>> from the fact that the internal representation of the strings does
>>>>> need to
>>>>> be identical, but what is passed to the user may be different due to
>>>>> truncation.
>>>>
>>>> Yes, the "quasi" might be a German thing, although I think is also
>>>> exists in English. I am open to any other suggestion.
>>>>
>>>> For the the quasi just expresses their actual state, we regard them as
>>>> identical, although the actual strings returned do not have to the
>>>> identical in the strcmp sense (due to different length). So they are
>>>> identical and at the same time they are not. That is a little "quasi"
>>>> to
>>>> me ;-)
>>>>
>>>> What about:
>>>>
>>>> prospect-identical?
>>>> source-identical?
>>>>
>>>>> That said, I don't have a replacement suggestion right this second.
>>>>
>>>>>> Should we have an "out-of-order" telco tomorrow to discuss this? As
>>>>>> we
>>>>>> need to finalize our wording by Monday in order for 383 to be an
>>>>>> errata,
>>>>>> I think we need to make progress before the weekend.
>>>>>
>>>>> I'm not sure if that will work with everyone at SC. It would coincide
>>>>> with
>>>>> the 10:00 AM technical papers sessions. I suppose though if people
>>>>> pipe up
>>>>> that they would be able to join, that would be good and I would be
>>>>> able to
>>>>> be on the call. Of course, as you say in your post script, we could
>>>>> pick
>>>>> another time, too.
>>>>
>>>> Obviously, I am fine with any earlier time slot, but that would not go
>>>> well with pacific time. I would have more again after 8 pm CET. Maybe
>>>> the people at SC suggest a time that fits into the program for them?
>>>>
>>>> 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
>>>>
>>
>>
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> 
> 
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-- 
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

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