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Subject: Re: [OMPI devel] opal / fortran / Flogical
From: Ralph Castain (rhc_at_[hidden])
Date: 2009-06-01 23:12:55


Just to throw some $0.002 into this overall discussion...

Not knowing this was going to be happening, I was actually about to
propose moving the opal/util/arch.c code back to the ompi layer. The
original move had caused quite a bit of angst due to the fortran
stuff. Originally, I had needed to make the move because the design
for modex-less operations needed to know the architecture prior to
launching the app. However, as things evolved, it turns out that this
isn't necessary at all - in fact, the launch system doesn't actually
take advantage of the ORTE layer knowing the arch.

So from the point of view of the current system, there is no value in
having the opal/util/arch.c code - it can be restored to the original
datatype area.

I realize that Rainer is pursuing a different objective, and that's
fine. My point here is that the original motivation for breaking the
abstraction barrier no longer exists, so whatever we do here is free
to reflect that change in requirement.

I would personally like to see OPAL retain its original objective and
avoid having Fortran knowledge down there.
Ralph

On Jun 1, 2009, at 3:02 PM, Rainer Keller wrote:

> Thanks, Jeff!
>
>
> On Monday 01 June 2009 04:53:19 pm Jeff Squyres wrote:
>> Per the MPI_Flogical issue -- I think Rainer just exposed some old
>> ugliness. We've apparently had MPI_Flogical defined in
>> ompi_config.h.in for a long, long time -- we used it in some places
>> and used ompi_fortran_logical_t in other places.
>>
>> Even though I *may* be responsible for this particular bit of
>> ugliness
>> way back in the past :-), I think the #define for MPI_Flogical should
>> be removed if for no other reason than 6-12 months from now when
>> someone else re-discovers it, they'll have to go lookup to see if
>> it's
>> a real MPI type -- which it's not. Even though it's longer, we
>> should
>> use ompi_fortran_logical_t everywhere.
>>
>> My $0.02.
>>
>> On Jun 1, 2009, at 1:23 PM, Brian W. Barrett wrote:
>>> Well, this may just be another sign that the push of the DDT to OPAL
>>> is a
>>> bad idea. That's been my opinion from the start, so I'm biased.
>>> But OPAL
>>> was intended to be single process systems portability, not MPI crud.
>>>
>>> Brian
>>>
>>> On Mon, 1 Jun 2009, Rainer Keller wrote:
>>>> Hmm, OK, I see.
>>>> However, I do see potentially a problem with work getting ddt on
>>>
>>> the OPAL
>>>
>>>> layer when we do have a fortran compiler with different alignment
>>>
>>> requirements
>>>
>>>> for the same-sized basic types...
>>>>
>>>> As far as I understand the OPAL layer to abstract away from
>>>
>>> underlying system
>>>
>>>> portability, libc-quirks, and compiler information.
>>>>
>>>> But I am perfectly fine with reverting this!
>>>> Let's discuss, maybe phone?
>>>>
>>>> Thanks,
>>>> Rainer
>>>>
>>>> On Monday 01 June 2009 10:38:51 am Jeff Squyres wrote:
>>>>> Hmm. I'm not sure that I like this commit.
>>>>>
>>>>> George, Brian, and I specifically kept Fortran out of (the non-
>>>>> generated code in) opal because the MPI layer is the *only* layer
>>>
>>> that
>>>
>>>>> uses Fortran. There was one or two minor abstraction breaks (you
>>>>> cited opal/util/arch.c), but now we have Fortran all throughout
>>>
>>> Opal.
>>>
>>>>> Hmmm... :-\
>>>>>
>>>>> Is MPI_Flogical a real type? I don't see it defined in the
>>>>> MPI-2.2
>>>>> latex sources, but I could be missing it. I *thought* we used
>>>>> ompi_fortran_logical_t internally because there was no officially
>>>>> sanctioned MPI_<foo> type for it...?
>
> --
> ------------------------------------------------------------------------
> Rainer Keller, PhD Tel: +1 (865) 241-6293
> Oak Ridge National Lab Fax: +1 (865) 241-4811
> PO Box 2008 MS 6164 Email: keller_at_[hidden]
> Oak Ridge, TN 37831-2008 AIM/Skype: rusraink
>
>
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