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Re: [MPIWG Fortran] Fwd: proper modern Fortran support for user-defined reductions
by Malcolm Cohen 20 Nov '22

20 Nov '22

Hi Jeff, No, my_function is not compatible with MPI_User_function_f18 as it has different characteristics. It is also unlikely to work in practice despite the Intel acceptance at compile time, as an assumed-rank descriptor is unlikely to be exactly the same as a Fortran-90 assumed-shapee array descriptor. Also REAL is not compatible with TYPE(*) so it fails on that front too. On a more philosophical note, I don’t quite see what purpose LEN is meant to achieve. Surely you just pass it the array slice you want to be reduced, no need to tell it the size separately, no? Cheers, -- ..............Malcolm Cohen, NAG Oxford/Tokyo. From: mpiwg-fortran <mpiwg-fortran-bounces(a)lists.mpi-forum.org> On Behalf Of Jeff Hammond via mpiwg-fortran Sent: Monday, November 21, 2022 12:09 AM To: MPI Forum <mpiwg-fortran(a)lists.mpi-forum.org> Cc: Jeff Hammond <jeff.science(a)gmail.com> Subject: [MPIWG Fortran] Fwd: proper modern Fortran support for user-defined reductions Brandon Cook raised an interesting issue w.r.t. user-defined reductions and Fortran 2008 in <https://github.com/mpi-forum/mpi-issues/issues/576> https://github.com/mpi-forum/mpi-issues/issues/576. I looked at this and it appears we can do something better (https://github.com/mpi-forum/mpi-issues/issues/576#issuecomment-1317157138) namely: abstract interface subroutine MPI_User_function_f18(invec, inoutvec, len, datatype) use mpi_f08, only : MPI_Datatype implicit none type(*), dimension(..), target, intent(in) :: invec type(*), dimension(..), target, intent(inout) :: inoutvec integer, intent(in) :: len type(MPI_Datatype), intent(in) :: datatype end subroutine end interface which allows the user to create their own reduce functions, e.g.: subroutine MY_function(invec, inoutvec, len, datatype) use mpi_f08, only : MPI_Datatype implicit none real, dimension(:), target, intent(in) :: invec real, dimension(:), target, intent(inout) :: inoutvec integer, intent(in) :: len type(MPI_Datatype), intent(in) :: datatype inoutvec = inoutvec + invec end subroutine Do people think this is worth proposing for MPI-5? It would require a new MPI_Op_create function, but already did one for large-count. Also, can a proper Fortran language lawyer like Bill Long confirm that MY_function is compatible with the abstract interface above? Intel Fortran doesn't complain, but I want to be sure. Thanks! Jeff -- Jeff Hammond jeff.science(a)gmail.com <mailto:[email protected]> http://jeffhammond.github.io/

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Fwd: proper modern Fortran support for user-defined reductions
by Jeff Hammond 20 Nov '22

20 Nov '22

Brandon Cook raised an interesting issue w.r.t. user-defined reductions and Fortran 2008 in https://github.com/mpi-forum/mpi-issues/issues/576. I looked at this and it appears we can do something better ( https://github.com/mpi-forum/mpi-issues/issues/576#issuecomment-1317157138) namely: abstract interface subroutine MPI_User_function_f18(invec, inoutvec, len, datatype) use mpi_f08, only : MPI_Datatype implicit none type(*), dimension(..), target, intent(in) :: invec type(*), dimension(..), target, intent(inout) :: inoutvec integer, intent(in) :: len type(MPI_Datatype), intent(in) :: datatype end subroutine end interface which allows the user to create their own reduce functions, e.g.: subroutine MY_function(invec, inoutvec, len, datatype) use mpi_f08, only : MPI_Datatype implicit none real, dimension(:), target, intent(in) :: invec real, dimension(:), target, intent(inout) :: inoutvec integer, intent(in) :: len type(MPI_Datatype), intent(in) :: datatype inoutvec = inoutvec + invec end subroutine Do people think this is worth proposing for MPI-5? It would require a new MPI_Op_create function, but already did one for large-count. Also, can a proper Fortran language lawyer like Bill Long confirm that MY_function is compatible with the abstract interface above? Intel Fortran doesn't complain, but I want to be sure. Thanks! Jeff -- Jeff Hammond jeff.science(a)gmail.com http://jeffhammond.github.io/

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Re: [MPIWG Fortran] "ELEMENTAL" keyword on mpi_f08 comparison operator functions
by Rolf Rabenseifner 12 Mar '22

12 Mar '22

Dear Reinhold, Jeff, Jeff, and all, Reinhold, thank you for your answer and your explanation by phone today. >> > It should be correct to add ELEMENTAL here and we should encourage that. Yes, I completely agree with this statement. One goal of the overloading is, that the following application code DO WHILE (ANY(request-array.NE.MPI_REQUEST_NULL)) MPI_TESTSOME(10, request_array, ...) END DO should work in the mpi and mpi_f08 module, i.e., for INTEGER request_array(10) and TYPE(MPI_Request), DIMENSION(10) :: request_array In principle, Reinhold's 1st item mentioned, that an implementation of an MPI library could do it in a different way by internaly checking the shape of the arguments (here a one-dimsional array with 10 elements and a scalar) and then returning internally doing the right comparisons and returning a corrrect result (here again a one-dimsional array with 10 elements). In this sense, requiring ELEMENTAL is not needed because it would restrict an implementation to do only the most easy solution ;-) Of course, doing the comparison only for scalars should be treated incorrect. The most simple and most clear way for implementors and users to tell them that the comparison must work for scalars and any one- or multi-dimensional array of handles, is to directly say that ELEMENTAL must be specified. I would recommend to add this as an errata, because we should have done this already in MPI-3.0, i.e., we should not have allowed the complicated way as mentioned in Reinhold's 1st item. Of course, restricting it to only scalar comparisons was never intended. The errata must be done at two locations: >> mpi_f08 in MPI-4.0 Section 19.1.2 page 793 lines 23-24: >> > * Overload the operators .EQ. and .NE. to allow the comparison >> > of these MPI handles with .EQ. , .NE. , == and /= . ELEMENTAL shall be specified to not exclude array comparisons. >> >> mpi module in MPI-4.0 Section 19.1.3 page 795 lines 35-37: >> * Define the derived type MPI_Status and all named handle types >> that are used in the mpi_f08 module. For these named handle >> types, overload the operators .EQ. and .NE. to allow handle >> comparison via the .EQ., .NE., == and /= operators. ELEMENTAL shall be specified to not exclude array comparisons. I included already a first draft for that erratum. Reinhold is not member of the mailing list, i.e. one of us should always take care that his answers are also broadcasted to "MPI-WG Fortran working group" <mpiwg-fortran(a)lists.mpi-forum.org> Best regards Rolf ----- Original Message ----- > From: "Rolf Rabenseifner" <rabenseifner(a)hlrs.de> > To: "Reinhold Bader" <Reinhold.Bader(a)lrz.de> > Cc: "Jeff Hammond" <jeff.science(a)gmail.com>, "MPI-WG Fortran working group" <mpiwg-fortran(a)lists.mpi-forum.org>, "Jeff > Squyres" <jsquyres(a)cisco.com> > Sent: Saturday, March 12, 2022 8:53:28 AM > Subject: Re: AW: [MPIWG Fortran] "ELEMENTAL" keyword on mpi_f08 comparison operator functions > I just resend Reinhold's answer to the list for the case that Reinhold is not > member of the list. > I'll try to call him to better understand his answer; and then he or I will come > back. > _________________ > Hello Rolf, > > apologies for the delayed response. Here my comments: > > 1. If an MPI implementation already implements the specifics of these operators [these 3 additional words were meant by Reinhold] > with assumed rank dummy arguments (with run-time checks for conformity > of rank and shape), > making these ELEMENTAL would not be possible. One would need to change the > implementation to have scalar arguments. Similar if multiple specifics > for different ranks are implemented. [by Rolf: I expect that no MPI library was implemented in such a complicated way.] > 2. Adding ELEMENTAL in an implementation will necessitate recompilation > of application codes > 3. Lack of portability for application codes seems to me to be less of a > problem than it is now, i.e., adding the ELEMENTAL requirement in > the spec would simply assure that implementations are not permitted > to limit themselves to the scalar case. > > Regards > Reinhold > >> -----Ursprüngliche Nachricht----- >> Von: Rolf Rabenseifner <rabenseifner(a)hlrs.de> >> Gesendet: Dienstag, 8. März 2022 11:59 >> An: Bader, Reinhold <Reinhold.Bader(a)lrz.de> >> Cc: Jeff Hammond <jeff.science(a)gmail.com>; MPI-WG Fortran working >> group <mpiwg-fortran(a)lists.mpi-forum.org> >> Betreff: Re: [MPIWG Fortran] "ELEMENTAL" keyword on mpi_f08 comparison >> operator functions >> >> Hello Reinhold, >> >> can you give as background information about this question on ELEMENTAL >> below. >> >> >> Our MPI handles are defined according to MPi-4.0 page 18 as >> >> TYPE, BIND(C) :: MPI_Comm >> INTEGER :: MPI_VAL >> END TYPE MPI_Comm >> >> and same for MPI_Group, ... >> >> >> The MPI standard specifies for both the mpi and the mpi_f08 module: >> >> mpi_f08 in MPI-4.0 Section 19.1.2 page 793 lines 23-24: >> > * Overload the operators .EQ. and .NE. to allow the comparison of these >> MPI >> > handles with .EQ. , .NE. , == and /= . >> >> mpi module in MPI-4.0 Section 19.1.3 page 795 lines 35-37: >> * Defi >> >> ne the derived type MPI_Status and all named handle types that are used in >> the >> mpi_f08 module. For these named handle types, overload the operators >> .EQ. and >> .NE. to allow handle comparison via the .EQ., .NE., == and /= operators. >> >> Best regards >> Rolf >> >> >> ----- Original Message ----- >> > From: "MPI-WG Fortran working group" >> > <mpiwg-fortran(a)lists.mpi-forum.org> >> > To: "MPI-WG Fortran working group" <mpiwg-fortran(a)lists.mpi- >> forum.org> >> > Cc: "Jeff Hammond" <jeff.science(a)gmail.com> >> > Sent: Tuesday, March 8, 2022 11:01:13 AM >> > Subject: Re: [MPIWG Fortran] "ELEMENTAL" keyword on mpi_f08 >> comparison >> > operator functions >> >> > It should be correct to add ELEMENTAL here and we should encourage that. >> > >> > I would argue that we should require ELEMENTAL in the place where it >> says: >> > >> > >> > * Overload the operators .EQ. and .NE. to allow the comparison of these >> MPI >> > handles with .EQ. , .NE. , == and /= . >> > [ https://www.mpi-forum.org/docs/mpi-3.1/mpi31-report/node409.htm | >> > https://www.mpi-forum.org/docs/mpi-3.1/mpi31-report/node409.htm ] (I >> > assume the text is unchanged in MPI-4) >> > >> > Jeff >> > >> > On Tue, Mar 8, 2022 at 1:19 AM Jeff Squyres (jsquyres) via >> > mpiwg-fortran < [ mailto:[email protected] | >> > mpiwg-fortran(a)lists.mpi-forum.org ] >> > > wrote: >> > >> > >> > Forum Fortran WG -- >> > >> > Any comments? >> > >> > I got one off-list reply explaining the use of ELEMENTAL, but I'm >> > curious as to what the Forum's response should be. >> > >> > I ask because the use of ELEMENTAL has an impact on MPI application >> portability. >> > E.g., if the Open MPI family of implementations use ELEMENTAL but the >> > MPICH family of implementations do not, that could be confusing for users. >> > >> > -- >> > Jeff Squyres >> > [ mailto:[email protected] | jsquyres(a)cisco.com ] >> > >> > ________________________________________ >> > From: mpiwg-fortran < [ >> > mailto:[email protected] | >> > mpiwg-fortran-bounces(a)lists.mpi-forum.org ] > on behalf of Jeff >> > Squyres >> > (jsquyres) via mpiwg-fortran < [ >> > mailto:[email protected] | >> > mpiwg-fortran(a)lists.mpi-forum.org ] > >> > Sent: Tuesday, March 1, 2022 10:24 AM >> > To: MPI Forum >> > Cc: Jeff Squyres (jsquyres) >> > Subject: [MPIWG Fortran] "ELEMENTAL" keyword on mpi_f08 comparison >> > operator functions >> > >> > An Open MPI user this morning requested that we add the "ELEMENTAL" >> > keyword to the mpi_f08 module eq / neq operator functions: [ >> > https://github.com/open-mpi/ompi/issues/10057 | >> > https://github.com/open-mpi/ompi/issues/10057 ] >> > >> > The only statement I can find in MPI-4.0 about the eq / neq operators >> > is section 19.1.2, "Fortran Support Through the mpi_f08 Module", only >> > says the following about the operator functions (p793, 22:23): >> > >> >> Overload the operators .EQ. and .NE. to allow the comparison of these >> >> MPI handles with .EQ., .NE., == and /=. >> > >> > This doesn't seem to allow or disallow the use of ELEMENTAL. >> > >> > What are the pros / cons of adding ELEMENTAL to the eq / neq operator >> functions? >> > >> > -- >> > Jeff Squyres >> > [ mailto:[email protected] | jsquyres(a)cisco.com ] >> > _______________________________________________ >> > mpiwg-fortran mailing list >> > [ mailto:[email protected] | >> > mpiwg-fortran(a)lists.mpi-forum.org ] [ >> > https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran | >> > https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran ] >> > _______________________________________________ >> > mpiwg-fortran mailing list >> > [ mailto:[email protected] | >> > mpiwg-fortran(a)lists.mpi-forum.org ] [ >> > https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran | >> > https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran ] >> > >> > >> > -- >> > Jeff Hammond >> > [ mailto:[email protected] | jeff.science(a)gmail.com ] [ >> > http://jeffhammond.github.io/ | http://jeffhammond.github.io/ ] >> > >> > _______________________________________________ >> > mpiwg-fortran mailing list >> > mpiwg-fortran(a)lists.mpi-forum.org >> > https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran >> >> -- >> Dr. Rolf Rabenseifner . . . . . . . . . .. email rabenseifner(a)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) . -- Dr. Rolf Rabenseifner . . . . . . . . . .. email rabenseifner(a)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) .

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Re: [MPIWG Fortran] "ELEMENTAL" keyword on mpi_f08 comparison operator functions
by Rolf Rabenseifner 12 Mar '22

12 Mar '22

I just resend Reinhold's answer to the list for the case that Reinhold is not member of the list. I'll try to call him to better understand his answer; and then he or I will come back. _________________ Hello Rolf, apologies for the delayed response. Here my comments: 1. If an MPI implementation already implements the specifics with assumed rank dummy arguments (with run-time checks for conformity of rank and shape), making these ELEMENTAL would not be possible. One would need to change the implementation to have scalar arguments. Similar if multiple specifics for different ranks are implemented. 2. Adding ELEMENTAL in an implementation will necessitate recompilation of application codes 3. Lack of portability for application codes seems to me to be less of a problem than it is now, i.e., adding the ELEMENTAL requirement in the spec would simply assure that implementations are not permitted to limit themselves to the scalar case. Regards Reinhold > -----Ursprüngliche Nachricht----- > Von: Rolf Rabenseifner <rabenseifner(a)hlrs.de> > Gesendet: Dienstag, 8. März 2022 11:59 > An: Bader, Reinhold <Reinhold.Bader(a)lrz.de> > Cc: Jeff Hammond <jeff.science(a)gmail.com>; MPI-WG Fortran working > group <mpiwg-fortran(a)lists.mpi-forum.org> > Betreff: Re: [MPIWG Fortran] "ELEMENTAL" keyword on mpi_f08 comparison > operator functions > > Hello Reinhold, > > can you give as background information about this question on ELEMENTAL > below. > > > Our MPI handles are defined according to MPi-4.0 page 18 as > > TYPE, BIND(C) :: MPI_Comm > INTEGER :: MPI_VAL > END TYPE MPI_Comm > > and same for MPI_Group, ... > > > The MPI standard specifies for both the mpi and the mpi_f08 module: > > mpi_f08 in MPI-4.0 Section 19.1.2 page 793 lines 23-24: > > * Overload the operators .EQ. and .NE. to allow the comparison of these > MPI > > handles with .EQ. , .NE. , == and /= . > > mpi module in MPI-4.0 Section 19.1.3 page 795 lines 35-37: > * Defi > > ne the derived type MPI_Status and all named handle types that are used in > the > mpi_f08 module. For these named handle types, overload the operators > .EQ. and > .NE. to allow handle comparison via the .EQ., .NE., == and /= operators. > > Best regards > Rolf > > > ----- Original Message ----- > > From: "MPI-WG Fortran working group" > > <mpiwg-fortran(a)lists.mpi-forum.org> > > To: "MPI-WG Fortran working group" <mpiwg-fortran(a)lists.mpi- > forum.org> > > Cc: "Jeff Hammond" <jeff.science(a)gmail.com> > > Sent: Tuesday, March 8, 2022 11:01:13 AM > > Subject: Re: [MPIWG Fortran] "ELEMENTAL" keyword on mpi_f08 > comparison > > operator functions > > > It should be correct to add ELEMENTAL here and we should encourage that. > > > > I would argue that we should require ELEMENTAL in the place where it > says: > > > > > > * Overload the operators .EQ. and .NE. to allow the comparison of these > MPI > > handles with .EQ. , .NE. , == and /= . > > [ https://www.mpi-forum.org/docs/mpi-3.1/mpi31-report/node409.htm | > > https://www.mpi-forum.org/docs/mpi-3.1/mpi31-report/node409.htm ] (I > > assume the text is unchanged in MPI-4) > > > > Jeff > > > > On Tue, Mar 8, 2022 at 1:19 AM Jeff Squyres (jsquyres) via > > mpiwg-fortran < [ mailto:[email protected] | > > mpiwg-fortran(a)lists.mpi-forum.org ] > > > wrote: > > > > > > Forum Fortran WG -- > > > > Any comments? > > > > I got one off-list reply explaining the use of ELEMENTAL, but I'm > > curious as to what the Forum's response should be. > > > > I ask because the use of ELEMENTAL has an impact on MPI application > portability. > > E.g., if the Open MPI family of implementations use ELEMENTAL but the > > MPICH family of implementations do not, that could be confusing for users. > > > > -- > > Jeff Squyres > > [ mailto:[email protected] | jsquyres(a)cisco.com ] > > > > ________________________________________ > > From: mpiwg-fortran < [ > > mailto:[email protected] | > > mpiwg-fortran-bounces(a)lists.mpi-forum.org ] > on behalf of Jeff > > Squyres > > (jsquyres) via mpiwg-fortran < [ > > mailto:[email protected] | > > mpiwg-fortran(a)lists.mpi-forum.org ] > > > Sent: Tuesday, March 1, 2022 10:24 AM > > To: MPI Forum > > Cc: Jeff Squyres (jsquyres) > > Subject: [MPIWG Fortran] "ELEMENTAL" keyword on mpi_f08 comparison > > operator functions > > > > An Open MPI user this morning requested that we add the "ELEMENTAL" > > keyword to the mpi_f08 module eq / neq operator functions: [ > > https://github.com/open-mpi/ompi/issues/10057 | > > https://github.com/open-mpi/ompi/issues/10057 ] > > > > The only statement I can find in MPI-4.0 about the eq / neq operators > > is section 19.1.2, "Fortran Support Through the mpi_f08 Module", only > > says the following about the operator functions (p793, 22:23): > > > >> Overload the operators .EQ. and .NE. to allow the comparison of these > >> MPI handles with .EQ., .NE., == and /=. > > > > This doesn't seem to allow or disallow the use of ELEMENTAL. > > > > What are the pros / cons of adding ELEMENTAL to the eq / neq operator > functions? > > > > -- > > Jeff Squyres > > [ mailto:[email protected] | jsquyres(a)cisco.com ] > > _______________________________________________ > > mpiwg-fortran mailing list > > [ mailto:[email protected] | > > mpiwg-fortran(a)lists.mpi-forum.org ] [ > > https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran | > > https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran ] > > _______________________________________________ > > mpiwg-fortran mailing list > > [ mailto:[email protected] | > > mpiwg-fortran(a)lists.mpi-forum.org ] [ > > https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran | > > https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran ] > > > > > > -- > > Jeff Hammond > > [ mailto:[email protected] | jeff.science(a)gmail.com ] [ > > http://jeffhammond.github.io/ | http://jeffhammond.github.io/ ] > > > > _______________________________________________ > > mpiwg-fortran mailing list > > mpiwg-fortran(a)lists.mpi-forum.org > > https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran > > -- > Dr. Rolf Rabenseifner . . . . . . . . . .. email rabenseifner(a)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) .

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Re: [MPIWG Fortran] "ELEMENTAL" keyword on mpi_f08 comparison operator functions
by Bader, Reinhold 12 Mar '22

12 Mar '22

Hello Rolf, apologies for the delayed response. Here my comments: 1. If an MPI implementation already implements the specifics with assumed rank dummy arguments (with run-time checks for conformity of rank and shape), making these ELEMENTAL would not be possible. One would need to change the implementation to have scalar arguments. Similar if multiple specifics for different ranks are implemented. 2. Adding ELEMENTAL in an implementation will necessitate recompilation of application codes 3. Lack of portability for application codes seems to me to be less of a problem than it is now, i.e., adding the ELEMENTAL requirement in the spec would simply assure that implementations are not permitted to limit themselves to the scalar case. Regards Reinhold > -----Ursprüngliche Nachricht----- > Von: Rolf Rabenseifner <rabenseifner(a)hlrs.de> > Gesendet: Dienstag, 8. März 2022 11:59 > An: Bader, Reinhold <Reinhold.Bader(a)lrz.de> > Cc: Jeff Hammond <jeff.science(a)gmail.com>; MPI-WG Fortran working > group <mpiwg-fortran(a)lists.mpi-forum.org> > Betreff: Re: [MPIWG Fortran] "ELEMENTAL" keyword on mpi_f08 comparison > operator functions > > Hello Reinhold, > > can you give as background information about this question on ELEMENTAL > below. > > > Our MPI handles are defined according to MPi-4.0 page 18 as > > TYPE, BIND(C) :: MPI_Comm > INTEGER :: MPI_VAL > END TYPE MPI_Comm > > and same for MPI_Group, ... > > > The MPI standard specifies for both the mpi and the mpi_f08 module: > > mpi_f08 in MPI-4.0 Section 19.1.2 page 793 lines 23-24: > > * Overload the operators .EQ. and .NE. to allow the comparison of these > MPI > > handles with .EQ. , .NE. , == and /= . > > mpi module in MPI-4.0 Section 19.1.3 page 795 lines 35-37: > * Defi > > ne the derived type MPI_Status and all named handle types that are used in > the > mpi_f08 module. For these named handle types, overload the operators > .EQ. and > .NE. to allow handle comparison via the .EQ., .NE., == and /= operators. > > Best regards > Rolf > > > ----- Original Message ----- > > From: "MPI-WG Fortran working group" > > <mpiwg-fortran(a)lists.mpi-forum.org> > > To: "MPI-WG Fortran working group" <mpiwg-fortran(a)lists.mpi- > forum.org> > > Cc: "Jeff Hammond" <jeff.science(a)gmail.com> > > Sent: Tuesday, March 8, 2022 11:01:13 AM > > Subject: Re: [MPIWG Fortran] "ELEMENTAL" keyword on mpi_f08 > comparison > > operator functions > > > It should be correct to add ELEMENTAL here and we should encourage that. > > > > I would argue that we should require ELEMENTAL in the place where it > says: > > > > > > * Overload the operators .EQ. and .NE. to allow the comparison of these > MPI > > handles with .EQ. , .NE. , == and /= . > > [ https://www.mpi-forum.org/docs/mpi-3.1/mpi31-report/node409.htm | > > https://www.mpi-forum.org/docs/mpi-3.1/mpi31-report/node409.htm ] (I > > assume the text is unchanged in MPI-4) > > > > Jeff > > > > On Tue, Mar 8, 2022 at 1:19 AM Jeff Squyres (jsquyres) via > > mpiwg-fortran < [ mailto:[email protected] | > > mpiwg-fortran(a)lists.mpi-forum.org ] > > > wrote: > > > > > > Forum Fortran WG -- > > > > Any comments? > > > > I got one off-list reply explaining the use of ELEMENTAL, but I'm > > curious as to what the Forum's response should be. > > > > I ask because the use of ELEMENTAL has an impact on MPI application > portability. > > E.g., if the Open MPI family of implementations use ELEMENTAL but the > > MPICH family of implementations do not, that could be confusing for users. > > > > -- > > Jeff Squyres > > [ mailto:[email protected] | jsquyres(a)cisco.com ] > > > > ________________________________________ > > From: mpiwg-fortran < [ > > mailto:[email protected] | > > mpiwg-fortran-bounces(a)lists.mpi-forum.org ] > on behalf of Jeff > > Squyres > > (jsquyres) via mpiwg-fortran < [ > > mailto:[email protected] | > > mpiwg-fortran(a)lists.mpi-forum.org ] > > > Sent: Tuesday, March 1, 2022 10:24 AM > > To: MPI Forum > > Cc: Jeff Squyres (jsquyres) > > Subject: [MPIWG Fortran] "ELEMENTAL" keyword on mpi_f08 comparison > > operator functions > > > > An Open MPI user this morning requested that we add the "ELEMENTAL" > > keyword to the mpi_f08 module eq / neq operator functions: [ > > https://github.com/open-mpi/ompi/issues/10057 | > > https://github.com/open-mpi/ompi/issues/10057 ] > > > > The only statement I can find in MPI-4.0 about the eq / neq operators > > is section 19.1.2, "Fortran Support Through the mpi_f08 Module", only > > says the following about the operator functions (p793, 22:23): > > > >> Overload the operators .EQ. and .NE. to allow the comparison of these > >> MPI handles with .EQ., .NE., == and /=. > > > > This doesn't seem to allow or disallow the use of ELEMENTAL. > > > > What are the pros / cons of adding ELEMENTAL to the eq / neq operator > functions? > > > > -- > > Jeff Squyres > > [ mailto:[email protected] | jsquyres(a)cisco.com ] > > _______________________________________________ > > mpiwg-fortran mailing list > > [ mailto:[email protected] | > > mpiwg-fortran(a)lists.mpi-forum.org ] [ > > https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran | > > https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran ] > > _______________________________________________ > > mpiwg-fortran mailing list > > [ mailto:[email protected] | > > mpiwg-fortran(a)lists.mpi-forum.org ] [ > > https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran | > > https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran ] > > > > > > -- > > Jeff Hammond > > [ mailto:[email protected] | jeff.science(a)gmail.com ] [ > > http://jeffhammond.github.io/ | http://jeffhammond.github.io/ ] > > > > _______________________________________________ > > mpiwg-fortran mailing list > > mpiwg-fortran(a)lists.mpi-forum.org > > https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran > > -- > Dr. Rolf Rabenseifner . . . . . . . . . .. email rabenseifner(a)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) .

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Re: [MPIWG Fortran] "ELEMENTAL" keyword on mpi_f08 comparison operator functions
by Jeff Squyres (jsquyres) 11 Mar '22

11 Mar '22

Rolf -- Did Reinhold reply? If he's not a member of this list, his reply wouldn't have been distributed to the entire list. -- Jeff Squyres jsquyres(a)cisco.com ________________________________________ From: mpiwg-fortran <mpiwg-fortran-bounces(a)lists.mpi-forum.org> on behalf of Rolf Rabenseifner via mpiwg-fortran <mpiwg-fortran(a)lists.mpi-forum.org> Sent: Tuesday, March 8, 2022 5:58 AM To: Reinhold Bader Cc: Rolf Rabenseifner; MPI-WG Fortran working group Subject: Re: [MPIWG Fortran] "ELEMENTAL" keyword on mpi_f08 comparison operator functions Hello Reinhold, can you give as background information about this question on ELEMENTAL below. Our MPI handles are defined according to MPi-4.0 page 18 as TYPE, BIND(C) :: MPI_Comm INTEGER :: MPI_VAL END TYPE MPI_Comm and same for MPI_Group, ... The MPI standard specifies for both the mpi and the mpi_f08 module: mpi_f08 in MPI-4.0 Section 19.1.2 page 793 lines 23-24: > * Overload the operators .EQ. and .NE. to allow the comparison of these MPI > handles with .EQ. , .NE. , == and /= . mpi module in MPI-4.0 Section 19.1.3 page 795 lines 35-37: * Defi ne the derived type MPI_Status and all named handle types that are used in the mpi_f08 module. For these named handle types, overload the operators .EQ. and .NE. to allow handle comparison via the .EQ., .NE., == and /= operators. Best regards Rolf ----- Original Message ----- > From: "MPI-WG Fortran working group" <mpiwg-fortran(a)lists.mpi-forum.org> > To: "MPI-WG Fortran working group" <mpiwg-fortran(a)lists.mpi-forum.org> > Cc: "Jeff Hammond" <jeff.science(a)gmail.com> > Sent: Tuesday, March 8, 2022 11:01:13 AM > Subject: Re: [MPIWG Fortran] "ELEMENTAL" keyword on mpi_f08 comparison operator functions > It should be correct to add ELEMENTAL here and we should encourage that. > > I would argue that we should require ELEMENTAL in the place where it says: > > > * Overload the operators .EQ. and .NE. to allow the comparison of these MPI > handles with .EQ. , .NE. , == and /= . > [ https://www.mpi-forum.org/docs/mpi-3.1/mpi31-report/node409.htm | > https://www.mpi-forum.org/docs/mpi-3.1/mpi31-report/node409.htm ] > (I assume the text is unchanged in MPI-4) > > Jeff > > On Tue, Mar 8, 2022 at 1:19 AM Jeff Squyres (jsquyres) via mpiwg-fortran < [ > mailto:[email protected] | mpiwg-fortran(a)lists.mpi-forum.org ] > > wrote: > > > Forum Fortran WG -- > > Any comments? > > I got one off-list reply explaining the use of ELEMENTAL, but I'm curious as to > what the Forum's response should be. > > I ask because the use of ELEMENTAL has an impact on MPI application portability. > E.g., if the Open MPI family of implementations use ELEMENTAL but the MPICH > family of implementations do not, that could be confusing for users. > > -- > Jeff Squyres > [ mailto:[email protected] | jsquyres(a)cisco.com ] > > ________________________________________ > From: mpiwg-fortran < [ mailto:[email protected] | > mpiwg-fortran-bounces(a)lists.mpi-forum.org ] > on behalf of Jeff Squyres > (jsquyres) via mpiwg-fortran < [ mailto:[email protected] | > mpiwg-fortran(a)lists.mpi-forum.org ] > > Sent: Tuesday, March 1, 2022 10:24 AM > To: MPI Forum > Cc: Jeff Squyres (jsquyres) > Subject: [MPIWG Fortran] "ELEMENTAL" keyword on mpi_f08 comparison operator > functions > > An Open MPI user this morning requested that we add the "ELEMENTAL" keyword to > the mpi_f08 module eq / neq operator functions: [ > https://github.com/open-mpi/ompi/issues/10057 | > https://github.com/open-mpi/ompi/issues/10057 ] > > The only statement I can find in MPI-4.0 about the eq / neq operators is section > 19.1.2, "Fortran Support Through the mpi_f08 Module", only says the following > about the operator functions (p793, 22:23): > >> Overload the operators .EQ. and .NE. to allow the comparison of these MPI >> handles with .EQ., .NE., == and /=. > > This doesn't seem to allow or disallow the use of ELEMENTAL. > > What are the pros / cons of adding ELEMENTAL to the eq / neq operator functions? > > -- > Jeff Squyres > [ mailto:[email protected] | jsquyres(a)cisco.com ] > _______________________________________________ > mpiwg-fortran mailing list > [ mailto:[email protected] | mpiwg-fortran(a)lists.mpi-forum.org ] > [ https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran | > https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran ] > _______________________________________________ > mpiwg-fortran mailing list > [ mailto:[email protected] | mpiwg-fortran(a)lists.mpi-forum.org ] > [ https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran | > https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran ] > > > -- > Jeff Hammond > [ mailto:[email protected] | jeff.science(a)gmail.com ] > [ http://jeffhammond.github.io/ | http://jeffhammond.github.io/ ] > > _______________________________________________ > mpiwg-fortran mailing list > mpiwg-fortran(a)lists.mpi-forum.org > https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran -- Dr. Rolf Rabenseifner . . . . . . . . . .. email rabenseifner(a)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(a)lists.mpi-forum.org https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran

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Re: [MPIWG Fortran] "ELEMENTAL" keyword on mpi_f08 comparison operator functions
by Rolf Rabenseifner 08 Mar '22

08 Mar '22

Hello Reinhold, can you give as background information about this question on ELEMENTAL below. Our MPI handles are defined according to MPi-4.0 page 18 as TYPE, BIND(C) :: MPI_Comm INTEGER :: MPI_VAL END TYPE MPI_Comm and same for MPI_Group, ... The MPI standard specifies for both the mpi and the mpi_f08 module: mpi_f08 in MPI-4.0 Section 19.1.2 page 793 lines 23-24: > * Overload the operators .EQ. and .NE. to allow the comparison of these MPI > handles with .EQ. , .NE. , == and /= . mpi module in MPI-4.0 Section 19.1.3 page 795 lines 35-37: * Define the derived type MPI_Status and all named handle types that are used in the mpi_f08 module. For these named handle types, overload the operators .EQ. and .NE. to allow handle comparison via the .EQ., .NE., == and /= operators. Best regards Rolf ----- Original Message ----- > From: "MPI-WG Fortran working group" <mpiwg-fortran(a)lists.mpi-forum.org> > To: "MPI-WG Fortran working group" <mpiwg-fortran(a)lists.mpi-forum.org> > Cc: "Jeff Hammond" <jeff.science(a)gmail.com> > Sent: Tuesday, March 8, 2022 11:01:13 AM > Subject: Re: [MPIWG Fortran] "ELEMENTAL" keyword on mpi_f08 comparison operator functions > It should be correct to add ELEMENTAL here and we should encourage that. > > I would argue that we should require ELEMENTAL in the place where it says: > > > * Overload the operators .EQ. and .NE. to allow the comparison of these MPI > handles with .EQ. , .NE. , == and /= . > [ https://www.mpi-forum.org/docs/mpi-3.1/mpi31-report/node409.htm | > https://www.mpi-forum.org/docs/mpi-3.1/mpi31-report/node409.htm ] > (I assume the text is unchanged in MPI-4) > > Jeff > > On Tue, Mar 8, 2022 at 1:19 AM Jeff Squyres (jsquyres) via mpiwg-fortran < [ > mailto:[email protected] | mpiwg-fortran(a)lists.mpi-forum.org ] > > wrote: > > > Forum Fortran WG -- > > Any comments? > > I got one off-list reply explaining the use of ELEMENTAL, but I'm curious as to > what the Forum's response should be. > > I ask because the use of ELEMENTAL has an impact on MPI application portability. > E.g., if the Open MPI family of implementations use ELEMENTAL but the MPICH > family of implementations do not, that could be confusing for users. > > -- > Jeff Squyres > [ mailto:[email protected] | jsquyres(a)cisco.com ] > > ________________________________________ > From: mpiwg-fortran < [ mailto:[email protected] | > mpiwg-fortran-bounces(a)lists.mpi-forum.org ] > on behalf of Jeff Squyres > (jsquyres) via mpiwg-fortran < [ mailto:[email protected] | > mpiwg-fortran(a)lists.mpi-forum.org ] > > Sent: Tuesday, March 1, 2022 10:24 AM > To: MPI Forum > Cc: Jeff Squyres (jsquyres) > Subject: [MPIWG Fortran] "ELEMENTAL" keyword on mpi_f08 comparison operator > functions > > An Open MPI user this morning requested that we add the "ELEMENTAL" keyword to > the mpi_f08 module eq / neq operator functions: [ > https://github.com/open-mpi/ompi/issues/10057 | > https://github.com/open-mpi/ompi/issues/10057 ] > > The only statement I can find in MPI-4.0 about the eq / neq operators is section > 19.1.2, "Fortran Support Through the mpi_f08 Module", only says the following > about the operator functions (p793, 22:23): > >> Overload the operators .EQ. and .NE. to allow the comparison of these MPI >> handles with .EQ., .NE., == and /=. > > This doesn't seem to allow or disallow the use of ELEMENTAL. > > What are the pros / cons of adding ELEMENTAL to the eq / neq operator functions? > > -- > Jeff Squyres > [ mailto:[email protected] | jsquyres(a)cisco.com ] > _______________________________________________ > mpiwg-fortran mailing list > [ mailto:[email protected] | mpiwg-fortran(a)lists.mpi-forum.org ] > [ https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran | > https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran ] > _______________________________________________ > mpiwg-fortran mailing list > [ mailto:[email protected] | mpiwg-fortran(a)lists.mpi-forum.org ] > [ https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran | > https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran ] > > > -- > Jeff Hammond > [ mailto:[email protected] | jeff.science(a)gmail.com ] > [ http://jeffhammond.github.io/ | http://jeffhammond.github.io/ ] > > _______________________________________________ > mpiwg-fortran mailing list > mpiwg-fortran(a)lists.mpi-forum.org > https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran -- Dr. Rolf Rabenseifner . . . . . . . . . .. email rabenseifner(a)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) .

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Re: [MPIWG Fortran] "ELEMENTAL" keyword on mpi_f08 comparison operator functions
by Jeff Hammond 08 Mar '22

08 Mar '22

It should be correct to add ELEMENTAL here and we should encourage that. I would argue that we should require ELEMENTAL in the place where it says: - Overload the operators .EQ. and .NE. to allow the comparison of these MPI handles with .EQ., .NE., == and /=. https://www.mpi-forum.org/docs/mpi-3.1/mpi31-report/node409.htm (I assume the text is unchanged in MPI-4) Jeff On Tue, Mar 8, 2022 at 1:19 AM Jeff Squyres (jsquyres) via mpiwg-fortran < mpiwg-fortran(a)lists.mpi-forum.org> wrote: > Forum Fortran WG -- > > Any comments? > > I got one off-list reply explaining the use of ELEMENTAL, but I'm curious > as to what the Forum's response should be. > > I ask because the use of ELEMENTAL has an impact on MPI application > portability. E.g., if the Open MPI family of implementations use ELEMENTAL > but the MPICH family of implementations do not, that could be confusing for > users. > > -- > Jeff Squyres > jsquyres(a)cisco.com > > ________________________________________ > From: mpiwg-fortran <mpiwg-fortran-bounces(a)lists.mpi-forum.org> on behalf > of Jeff Squyres (jsquyres) via mpiwg-fortran < > mpiwg-fortran(a)lists.mpi-forum.org> > Sent: Tuesday, March 1, 2022 10:24 AM > To: MPI Forum > Cc: Jeff Squyres (jsquyres) > Subject: [MPIWG Fortran] "ELEMENTAL" keyword on mpi_f08 comparison > operator functions > > An Open MPI user this morning requested that we add the "ELEMENTAL" > keyword to the mpi_f08 module eq / neq operator functions: > https://github.com/open-mpi/ompi/issues/10057 > > The only statement I can find in MPI-4.0 about the eq / neq operators is > section 19.1.2, "Fortran Support Through the mpi_f08 Module", only says the > following about the operator functions (p793, 22:23): > > > Overload the operators .EQ. and .NE. to allow the comparison of these > MPI handles with .EQ., .NE., == and /=. > > This doesn't seem to allow or disallow the use of ELEMENTAL. > > What are the pros / cons of adding ELEMENTAL to the eq / neq operator > functions? > > -- > Jeff Squyres > jsquyres(a)cisco.com > _______________________________________________ > mpiwg-fortran mailing list > mpiwg-fortran(a)lists.mpi-forum.org > https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran > _______________________________________________ > mpiwg-fortran mailing list > mpiwg-fortran(a)lists.mpi-forum.org > https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran > -- Jeff Hammond jeff.science(a)gmail.com http://jeffhammond.github.io/

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Re: [MPIWG Fortran] "ELEMENTAL" keyword on mpi_f08 comparison operator functions
by Jeff Squyres (jsquyres) 07 Mar '22

07 Mar '22

Forum Fortran WG -- Any comments? I got one off-list reply explaining the use of ELEMENTAL, but I'm curious as to what the Forum's response should be. I ask because the use of ELEMENTAL has an impact on MPI application portability. E.g., if the Open MPI family of implementations use ELEMENTAL but the MPICH family of implementations do not, that could be confusing for users. -- Jeff Squyres jsquyres(a)cisco.com ________________________________________ From: mpiwg-fortran <mpiwg-fortran-bounces(a)lists.mpi-forum.org> on behalf of Jeff Squyres (jsquyres) via mpiwg-fortran <mpiwg-fortran(a)lists.mpi-forum.org> Sent: Tuesday, March 1, 2022 10:24 AM To: MPI Forum Cc: Jeff Squyres (jsquyres) Subject: [MPIWG Fortran] "ELEMENTAL" keyword on mpi_f08 comparison operator functions An Open MPI user this morning requested that we add the "ELEMENTAL" keyword to the mpi_f08 module eq / neq operator functions: https://github.com/open-mpi/ompi/issues/10057 The only statement I can find in MPI-4.0 about the eq / neq operators is section 19.1.2, "Fortran Support Through the mpi_f08 Module", only says the following about the operator functions (p793, 22:23): > Overload the operators .EQ. and .NE. to allow the comparison of these MPI handles with .EQ., .NE., == and /=. This doesn't seem to allow or disallow the use of ELEMENTAL. What are the pros / cons of adding ELEMENTAL to the eq / neq operator functions? -- Jeff Squyres jsquyres(a)cisco.com _______________________________________________ mpiwg-fortran mailing list mpiwg-fortran(a)lists.mpi-forum.org https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran

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"ELEMENTAL" keyword on mpi_f08 comparison operator functions
by Jeff Squyres (jsquyres) 01 Mar '22

01 Mar '22

An Open MPI user this morning requested that we add the "ELEMENTAL" keyword to the mpi_f08 module eq / neq operator functions: https://github.com/open-mpi/ompi/issues/10057 The only statement I can find in MPI-4.0 about the eq / neq operators is section 19.1.2, "Fortran Support Through the mpi_f08 Module", only says the following about the operator functions (p793, 22:23): > Overload the operators .EQ. and .NE. to allow the comparison of these MPI handles with .EQ., .NE., == and /=. This doesn't seem to allow or disallow the use of ELEMENTAL. What are the pros / cons of adding ELEMENTAL to the eq / neq operator functions? -- Jeff Squyres jsquyres(a)cisco.com

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