[mpi-22] FW: [mpi-21] Proposal: MPI_OFFSET built-in type

[Jeff Squyres]

Don't forget MPI::OFFSET (and MPI::AINT).

And they should be const.  ;-)

On Jan 24, 2008, at 12:55 PM, Rajeev Thakur wrote:

> Is it an interface change? It would be an addition to the set of  
> predefined
> types, such as MPI_INT, MPI_CHAR, so it should just work I think.
>
>>> MPI Datatype: MPI_OFFSET
>>> Corresponding C type: long long int
>>> Corresponding Fortran type: INTEGER(KIND=MPI_OFFSET_KIND)
>
> The corresponding C type should be "implementation defined". It  
> could be int
> for example in an implementation that only supports 32-bit file sizes.
>
> Rajeev
>
>
>> -----Original Message-----
>> From: mpi-22-bounces_at_[hidden]
>> [mailto:mpi-22-bounces_at_[hidden]] On Behalf Of Richard Graham
>> Sent: Thursday, January 24, 2008 11:48 AM
>> To: mpi-22_at_[hidden]
>> Subject: Re: [mpi-22] FW: [mpi-21] Proposal: MPI_OFFSET built-in type
>>
>> Do you think this should go into 2.2 or 3.0 ?  I ask not
>> because the change
>> is large, but because it will change the signature of several
>> interface
>> functions (presumably marking the older functions as deprecated - for
>> removal in X number of years).  There is another change that
>> I would like to
>> see added to the standard, which is adding a way to convey  
>> information
>> between MPI_Alloc_mem() to the functions using this memory,
>> w/o forcing the
>> implementations to try and use all sorts of non-portable
>> solutions to figure
>> out if this memory can be used "as-is" by the network layer,
>> of if it needs
>> to be "prepared" (pinned, and ?).
>>
>> It seems prudent to combine such interface changes into the
>> smallest number
>> of changes (1 is preferred).
>>
>> What do you think ?
>> Rich
>>
>>
>> On 1/24/08 12:18 PM, "Rajeev Thakur" <thakur_at_[hidden]> wrote:
>>
>>> A similar one is needed for MPI_Aint.
>>>
>>> Rajeev
>>>
>>>> -----Original Message-----
>>>> From: mpi-22-bounces_at_[hidden]
>>>> [mailto:mpi-22-bounces_at_[hidden]] On Behalf Of Richard Graham
>>>> Sent: Thursday, January 24, 2008 11:09 AM
>>>> To: mpi-22_at_[hidden]
>>>> Subject: [mpi-22] FW: [mpi-21] Proposal: MPI_OFFSET built-in type
>>>>
>>>> Moving this to the appropriate list.
>>>>
>>>> Rich
>>>>
>>>> ------ Forwarded Message
>>>> From: Robert Latham <robl_at_[hidden]>
>>>> Reply-To: "Mailing list for discussion of MPI 2.1"
>>>> <mpi-21_at_[hidden]>
>>>> Date: Thu, 24 Jan 2008 10:41:52 -0600
>>>> To: <mpi-21_at_[hidden]>
>>>> Subject: [mpi-21] Proposal: MPI_OFFSET built-in type
>>>>
>>>> I hope this is less contentious than adding 'const' keywords...
>>>>
>>>>
>>>> I would like to propose a new built-in type MPI_OFFSET,
>> defined to be
>>>> a type corresponding to INTEGER(KIND=MPI_OFFSET_KIND) or MPI_Offset
>>>>
>>>> This is a minor addition to the standard, which would have
>> no impact
>>>> on existing code while serving to simplify code which
>> exchanges file
>>>> offsets among processes.
>>>>
>>>> There is a workaround in the standard: a user can define a
>> type from
>>>> MPI_BYTE:
>>>>
>>>> MPI_Type_contiguous(sizeof(MPI_Offset), MPI_BYTE, &offtype);
>>>>
>>>> However, it would clearly be more convienient to operate
>> on built-in
>>>> types.
>>>>
>>>> MPI Datatype: MPI_OFFSET
>>>> Corresponding C type: long long int
>>>> Corresponding Fortran type: INTEGER(KIND=MPI_OFFSET_KIND)
>>>>
>>>>
>>>> Thanks
>>>> ==rob
>>>>
>>>> -- 
>>>> Rob Latham
>>>> Mathematics and Computer Science Division    A215 0178
>> EA2D B059 8CDF
>>>> Argonne National Lab, IL USA                 B29D F333
>> 664A 4280 315B
>>>> _______________________________________________
>>>> mpi-21 mailing list
>>>> mpi-21_at_[hidden]
>>>> http://lists.cs.uiuc.edu/mailman/listinfo/mpi-21
>>>>
>>>> ------ End of Forwarded Message
>>>>
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>>>>
>>>
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>
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-- 
Jeff Squyres
Cisco Systems