[MPIWG Fortran] Type of MPI_Status
Rolf Rabenseifner
rabenseifner at hlrs.de
Sat Mar 15 07:38:17 CDT 2014
Dear Junchao,
As long as you use status%MPI_SOURCE in an expression,
all is fine.
If you pass it to an application routine dummy argument
that is defined as INTEGER and your status%MPI_SOURCE
is define as INTEGER(C_INT) then you may get compiler
warnings or errors if size of both INTEGER types is different.
CALL foo(status%MPI_SOURCE)
with
SUBROUTINE foo(rank)
INTEGER :: rank
Best regards
Rolf
----- Original Message -----
> From: "Junchao Zhang" <jczhang at mcs.anl.gov>
> To: "MPI-WG Fortran working group" mpi-forum.org>
> Sent: Saturday, March 15, 2014 11:54:38 AM
> Subject: Re: [MPIWG Fortran] Type of MPI_Status
>
>
>
> My point is, with the C_INT implementation of MPI_Status, there
> should be no compilation warnings AND runtime errors, even if
> INTEGER kind is not c_int, since users can only operate MPI_Status
> through their public interfaces, in which we take care of data
> conversion.
>
>
> But for other arguments of type INTEGER or array of INTEGERs, I can
> not change their type. Users pass in an array of INTEGERs, I can not
> pretend they are c_int and don't do conversion.
>
>
>
> --Junchao Zhang
>
>
> On Sat, Mar 15, 2014 at 3:33 AM, Rolf Rabenseifner <
> rabenseifner at hlrs.de > wrote:
>
>
> Junchao,
>
> With the erratum ticket #415, your implementation
> with INTEGER(C_INT) is clearly wrong,
> but who cares as long as an application programmer cannot
> write an application code that produces compilation errors
> or warnings or infos due to your wrong implementation
> of TYPE(MPI_Status).
>
> I do not exactly now the rules about Fortran subroutine
> prototype and overloading where handing over a INTEGER rank
> or a INTEGER(C_INT) rank may cause to choose different interfaces.
>
> Maybe that Bill Long should comment on such strange things
> before you define any field within TYPE(MPI_Status) or
> any dummy argument in a routine declaration as INTEGER(C_INT)
> instead of INTEGER as defined in MPI-3.0.
>
>
> Best regards
> Rolf
>
> ----- Original Message -----
> > From: "Junchao Zhang" < jczhang at mcs.anl.gov >
> > To: "MPI-WG Fortran working group" mpi-forum.org >
>
>
> > Sent: Saturday, March 15, 2014 12:11:35 AM
> > Subject: Re: [MPIWG Fortran] Type of MPI_Status
> >
> >
> >
> > Not sure if it is worth discussing. Even if INTEGER and C_INT are
> > of
> > different size, I think I can still use C_INT in MPI_Status.
> >
> >
> >
> > TYPE, BIND(C) :: MPI_Status
> > INTEGER(C_INT) :: MPI_SOURCE, MPI_TAG, MPI_ERROR
> > ... ! other fields
> > END TYPE MPI_Status
> >
> >
> > Since MPI_Status is a derived datatype, users access it through its
> > public interfaces(i.e., %MPI_SOURCE, ..., MPI_STATUS_SIZE).
> > As long as MPI_STATUS_SIZE >= sizeof(MPI_STATUS)/sizeof(INTEGER),
> > who
> > cares its internals.
> >
> >
> >
> >
> >
> > --Junchao Zhang
> >
> >
> > On Thu, Mar 13, 2014 at 10:56 AM, Rolf Rabenseifner <
> > rabenseifner at hlrs.de > wrote:
> >
> >
> > Jeff is right.
> > Bill's theoretical statement is also correct.
> >
> > And ticket#415 is also correct because it resolves an inconsistency
> > within the mpi_f08 interface.
> >
> > Strange theoretical discussions are also there for
> > long Fortran INTEGER may not be identical with some shorter
> > INTEGER(C_int).
> > As a side effect also solved by this ticket.
> >
> >
> > Rolf
> >
> > ----- Original Message -----
> >
> > > From: "Jeff Hammond" < jeff.science at gmail.com >
> > > To: "MPI-WG Fortran working group" mpi-forum.org >
> > > Sent: Thursday, March 13, 2014 4:12:56 PM
> > > Subject: Re: [MPIWG Fortran] Type of MPI_Status
> > >
> > > MPI should test for interoperability of Fortran's default integer
> > > and
> > > light the machine room on fire if it is not.
> > >
> > > Jeff
> > >
> > > On Thu, Mar 13, 2014 at 8:58 AM, Bill Long < longb at cray.com >
> > > wrote:
> > > > This does raise an earlier issue that it is
> >
> >
> > > > possible that Fortran’s default INTEGER is not an interoperable
> > > > type, and thus the MPI_Status type should not be a BIND(C) type
> > > > if
> > > > it has INTEGER components. Having BIND(C) does allow you to
> > > > declare a C global name MPI_STATUS_IGNORE in Fortran, which
> > > > solves
> > > > one problem nicely. I don’t see any advantage to having INTEGER
> > > > components (as opposed to INTEGER(C_Int), for example). So this
> > > > seems to represent the worse of the two options.
> > > >
> > > > Cheers,
> > > > Bill
> > > >
> > > >
> > > >
> > > > On Mar 13, 2014, at 8:36 AM, Jeff Squyres (jsquyres)
> > > > < jsquyres at cisco.com > wrote:
> > > >
> > > >> Done. Good catch:
> > > >>
> > > >> https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/415
> > > >>
> > > >> This is a trivial ticket, but if you could make sure it's ok,
> > > >> I'll
> > > >> send it to the mpi-forum list so that it can get added to the
> > > >> next meeting's agenda.
> > > >>
> > > >>
> > > >> On Mar 13, 2014, at 1:51 AM, Rolf Rabenseifner
> > > >> < rabenseifner at hlrs.de > wrote:
> > > >>
> > > >>> Jeff and Junchao,
> > > >>>
> > > >>> it is a missing word INTEGER in this part of the sentence
> > > >>>
> > > >>> In whole MPI these three values are in Fortran INTEGER and
> > > >>> nothing else
> > > >>>
> > > >>> Junchao, thank you for the hint that an erratum is neede
> > > >>> to prevent from such misinterpretation
> > > >>>
> > > >>> Jeff, please can you file the errata ticket resulting in
> > > >>>
> > > >>> ... containing three public INTEGER fields named ...
> > > >>>
> > > >>> Best regards
> > > >>> Rolf
> > > >>>
> > > >>>
> > > >>> ----- Original Message -----
> > > >>>> From: "Junchao Zhang" < jczhang at mcs.anl.gov >
> > > >>>> To: "MPI-WG Fortran working group"
> >
> >
> > > >>>> mpi-forum.org >
> > > >>>> Sent: Thursday, March 13, 2014 4:49:49 AM
> > > >>>> Subject: [MPIWG Fortran] Type of MPI_Status
> > > >>>>
> > > >>>>
> > > >>>>
> > > >>>>
> > > >>>> Hello,
> > > >>>>
> > > >>>>
> > > >>>> p30 of MPI3 says "In Fortran with USE mpi or INCLUDE
> > > >>>> ’mpif.h’,
> > > >>>> status
> > > >>>> is an array of INTEGERs of size MPI_STATUS_SIZE. ..., With
> > > >>>> Fortran
> > > >>>> USE mpi_f08, status is defined as the Fortran BIND(C)
> > > >>>> derived
> > > >>>> type
> > > >>>> TYPE(MPI_Status) containing three public fields named
> > > >>>> MPI_SOURCE
> > > >>>> ,
> > > >>>> MPI_TAG , and MPI_ERROR"
> > > >>>>
> > > >>>> In other words, it does't say type of the three public
> > > >>>> fields
> > > >>>> must be
> > > >>>> INTEGER. So, in mpi_f08, can I declare MPI_Status as
> > > >>>>
> > > >>>>
> > > >>>> TYPE, BIND(C) :: MPI_Status
> > > >>>> INTEGER(C_INT) :: MPI_SOURCE, MPI_TAG, MPI_ERROR
> > > >>>> ... ! other fields
> > > >>>> END TYPE MPI_Status
> > > >>>>
> > > >>>>
> > > >>>> I find it makes MPI_Status binding easier. Since this type
> > > >>>> is
> > > >>>> interoperable with C, I do not need to allocate temp
> > > >>>> variables
> > > >>>> to do
> > > >>>> type conversion when INTEGER is not a C_INT.
> > > >>>>
> > > >>>>
> > > >>>>
> > > >>>> --Junchao Zhang
> > > >>>> _______________________________________________
> > > >>>> mpiwg-fortran mailing list
> > > >>>> mpiwg-fortran at lists.mpi-forum.org
> > > >>>> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-fortran
> > > >>>
> > > >>> --
> > > >>> Dr. Rolf Rabenseifner . . . . . . . . . .. email
> > > >>> rabenseifner at hlrs.de
> > > >>> High Performance Computing Center (HLRS) . phone
> > > >>> ++49(0)711/685-65530
> > > >>> University of Stuttgart . . . . . . . . .. fax ++49(0)711 /
> > > >>> 685-65832
> > > >>> Head of Dpmt Parallel Computing . . .
> > > >>> www.hlrs.de/people/rabenseifner
> > > >>> Nobelstr. 19, D-70550 Stuttgart, Germany . . . . (Office:
> > > >>> Room
> > > >>> 1.307)
> > > >>> _______________________________________________
> > > >>> mpiwg-fortran mailing list
> > > >>> mpiwg-fortran at lists.mpi-forum.org
> > > >>> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-fortran
> > > >>
> > > >>
> > > >> --
> > > >> Jeff Squyres
> > > >> jsquyres at cisco.com
> > > >> For corporate legal information go to:
> > > >> http://www.cisco.com/web/about/doing_business/legal/cri/
> > > >>
> > > >> _______________________________________________
> > > >> mpiwg-fortran mailing list
> > > >> mpiwg-fortran at lists.mpi-forum.org
> > > >> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-fortran
> > > >
> > > > Bill Long
> > > > longb at cray.com
> > > > Fortran Technical Suport & voice:
> > > > 651-605-9024
> > > > Bioinformatics Software Development fax:
> > > > 651-605-9142
> > > > Cray Inc./ Cray Plaza, Suite 210/ 380 Jackson St./ St. Paul, MN
> > > > 55101
> > > >
> > > >
> > > > _______________________________________________
> > > > mpiwg-fortran mailing list
> > > > mpiwg-fortran at lists.mpi-forum.org
> > > > http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-fortran
> > >
> > >
> > >
> > > --
> > > Jeff Hammond
> > > jeff.science at gmail.com
> > > _______________________________________________
> > > mpiwg-fortran mailing list
> > > mpiwg-fortran at lists.mpi-forum.org
> > > http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-fortran
> >
> > --
> > Dr. Rolf Rabenseifner . . . . . . . . . .. email
> > rabenseifner at hlrs.de
> > High Performance Computing Center (HLRS) . phone
> > ++49(0)711/685-65530
> > University of Stuttgart . . . . . . . . .. fax ++49(0)711 /
> > 685-65832
> > Head of Dpmt Parallel Computing . . .
> > www.hlrs.de/people/rabenseifner
> > Nobelstr. 19, D-70550 Stuttgart, Germany . . . . (Office: Room
> > 1.307)
> > _______________________________________________
> > mpiwg-fortran mailing list
> > mpiwg-fortran at lists.mpi-forum.org
> > http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-fortran
> >
> > _______________________________________________
> > mpiwg-fortran mailing list
> > mpiwg-fortran at lists.mpi-forum.org
> > http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-fortran
>
> --
> Dr. Rolf Rabenseifner . . . . . . . . . .. email rabenseifner at hlrs.de
> High Performance Computing Center (HLRS) . phone ++49(0)711/685-65530
> University of Stuttgart . . . . . . . . .. fax ++49(0)711 / 685-65832
> Head of Dpmt Parallel Computing . . . www.hlrs.de/people/rabenseifner
> Nobelstr. 19, D-70550 Stuttgart, Germany . . . . (Office: Room 1.307)
> _______________________________________________
> mpiwg-fortran mailing list
> mpiwg-fortran at lists.mpi-forum.org
> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-fortran
>
> _______________________________________________
> mpiwg-fortran mailing list
> mpiwg-fortran at lists.mpi-forum.org
> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-fortran
--
Dr. Rolf Rabenseifner . . . . . . . . . .. email rabenseifner at hlrs.de
High Performance Computing Center (HLRS) . phone ++49(0)711/685-65530
University of Stuttgart . . . . . . . . .. fax ++49(0)711 / 685-65832
Head of Dpmt Parallel Computing . . . www.hlrs.de/people/rabenseifner
Nobelstr. 19, D-70550 Stuttgart, Germany . . . . (Office: Room 1.307)
More information about the mpiwg-fortran
mailing list