December 2016 - mpi-forum - mailman3.cels.anl.gov

Re: [Mpi-forum] Interest of changing lower bound in MPI_Type_create_resized
by Thakur, Rajeev 08 Dec '16

08 Dec '16

When MPI sends a message, the second datatype is taken from the location (lower bound + extent), the third datatype from (lower bound + 2*extent), and so on. So the lower bound does affect what is sent. Rajeev > On Dec 8, 2016, at 7:54 AM, lecas(a)idris.fr <dimitri.lecas(a)idris.fr> wrote: > > Hi, > > In MPI_Type_create_resized we can change the extent and the lower bound. > > I don't understand what is the interest of changing the lower bound, > since for sending message, only the extent is used. > > Is there an example where the value for lower bound in > MPI_Type_create_resized have a real impact ? > > Thanks > > -- > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > Dimitri Lecas > > > _______________________________________________ > mpi-forum mailing list > mpi-forum(a)lists.mpi-forum.org > https://lists.mpi-forum.org/mailman/listinfo/mpi-forum _______________________________________________ mpi-forum mailing list mpi-forum(a)lists.mpi-forum.org https://lists.mpi-forum.org/mailman/listinfo/mpi-forum

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Interest of changing lower bound in MPI_Type_create_resized
by lecas＠idris.fr 08 Dec '16

08 Dec '16

Hi, In MPI_Type_create_resized we can change the extent and the lower bound. I don't understand what is the interest of changing the lower bound, since for sending message, only the extent is used. Is there an example where the value for lower bound in MPI_Type_create_resized have a real impact ? Thanks -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Dimitri Lecas _______________________________________________ mpi-forum mailing list mpi-forum(a)lists.mpi-forum.org https://lists.mpi-forum.org/mailman/listinfo/mpi-forum

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Slides for Dec 2016 Meeting
by Bland, Wesley 07 Dec '16

07 Dec '16

For anyone who is presenting slides this meeting, please send them to me so I can upload them to the website. Thanks, Wesley _______________________________________________ mpi-forum mailing list mpi-forum(a)lists.mpi-forum.org https://lists.mpi-forum.org/mailman/listinfo/mpi-forum

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Re: [Mpi-forum] The Progress Engine
by Jeff Hammond 07 Dec '16

07 Dec '16

This question relates to implementation details, not the MPI standard, so this isn't the right place for it. Can you post this on StackOverflow? That's probably the best place for it. Lots of MPI+MPICH experts are active on StackOverflow... Best, Jeff On Wed, Dec 7, 2016 at 6:03 AM, Roman Tereshkov <rtereshkov(a)gmail.com> wrote: > Hi, everyone! > > I have a challenge from my scientific supervisor – I have to understand > how send & recv operations work in pt2pt communication. He said that I have > to find some magic stuff like "The Progress Engine" because that`s the main > thing which allows a message to pass from one process to another (that`s > how I understand him). So, I started with the MPICH code from "fossies [.] > org". Started with MPI_Send function and here I found functions > MPID_Progress_start/wait/end. Is it "The Progress Engine" thing? If yes, > then why when I try to check what code do these functions contain, I get > only their description? I mean there is no code.. just prototypes and > description, and that`s it. Also, I googled information about TPE and > "MPICH Wiki" says that TPE is implemented as MPIDI_CH3I_Progress. So, I > found this function in the implementation but at which point is it called? > Well, maybe my understanding of "The Progress Engine" mechanism is > incorrect? Tell me where am I wrong, please. > > _______________________________________________ > mpi-forum mailing list > mpi-forum(a)lists.mpi-forum.org > https://lists.mpi-forum.org/mailman/listinfo/mpi-forum > -- Jeff Hammond jeff.science(a)gmail.com http://jeffhammond.github.io/ _______________________________________________ mpi-forum mailing list mpi-forum(a)lists.mpi-forum.org https://lists.mpi-forum.org/mailman/listinfo/mpi-forum

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The Progress Engine
by Roman Tereshkov 07 Dec '16

07 Dec '16

Hi, everyone! I have a challenge from my scientific supervisor – I have to understand how send & recv operations work in pt2pt communication. He said that I have to find some magic stuff like "The Progress Engine" because that`s the main thing which allows a message to pass from one process to another (that`s how I understand him). So, I started with the MPICH code from "fossies [.] org". Started with MPI_Send function and here I found functions MPID_Progress_start/wait/end. Is it "The Progress Engine" thing? If yes, then why when I try to check what code do these functions contain, I get only their description? I mean there is no code.. just prototypes and description, and that`s it. Also, I googled information about TPE and "MPICH Wiki" says that TPE is implemented as MPIDI_CH3I_Progress. So, I found this function in the implementation but at which point is it called? Well, maybe my understanding of "The Progress Engine" mechanism is incorrect? Tell me where am I wrong, please. _______________________________________________ mpi-forum mailing list mpi-forum(a)lists.mpi-forum.org https://lists.mpi-forum.org/mailman/listinfo/mpi-forum

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Please register for next week's meeting
by Jeff Squyres (jsquyres) 01 Dec '16

01 Dec '16

If you have not already done so, please register for next week's meeting ASAP -- we need accurate counts for the catering and for quorum. http://mpi-forum.org/meetings/2016/12/logistics Thanks! -- Jeff Squyres jsquyres(a)cisco.com For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/ _______________________________________________ mpi-forum mailing list mpi-forum(a)lists.mpi-forum.org https://lists.mpi-forum.org/mailman/listinfo/mpi-forum

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