Dear Gilles, sorry to ask you again and to be frustrating, basically is this what I shall do for each CPU:
CALL MPI_ISEND(send_messageL, MsgLength, MPI_DOUBLE_COMPLEX, MPIdata%rank-1, MPIdata%rank, MPI_COMM_WORLD, REQUEST(1), MPIdata%iErr) CALL MPI_IRECV(recv_messageR, MsgLength, MPI_DOUBLE_COMPLEX, MPIdata%rank+1, MPIdata%rank+1, MPI_COMM_WORLD, REQUEST(2), MPIdata%iErr) and then CALL MPI_WAITALL(nMsg,REQUEST(1:2),send_status_list,MPIdata%iErr) Am I correct? Thanks thanks again Diego On 30 September 2015 at 17:18, Gilles Gouaillardet < gilles.gouaillar...@gmail.com> wrote: > Diego, > > there is some confusion here... > MPI_Waitall is not a collective operations, and a given tasks can only > wait the requests it initiated. > > bottom line, each task does exactly one send and one recv, right ? > in this case, you want to have an array of two requests, isend with the > first element and irecv with the second element, and then waitall the array > of size 2 > note this is not equivalent to doing two MPI_Wait in a row, since that > would be prone to deadlock > > Cheers, > > Gilles > > On Wednesday, September 30, 2015, Diego Avesani <diego.aves...@gmail.com> > wrote: > >> Dear all, >> thank for the explanation, but something is not clear to me. >> I have 4 CPUs. I use only three of them to send, let say: >> CPU 0 send to CPU 1 >> CPU 1 send to CPU 2 >> CPU 2 send to CPU 3 >> >> only three revive, let's say; >> CPU 1 from CPU 0 >> CPU 2 from CPU 1 >> CPU 3 from CPU 2 >> >> so I use ALLOCATE(send_request(3)) >> >> this mean that in the call I have: >> CALL MPI_ISEND(send_messageL, MsgLength, MPI_DOUBLE_COMPLEX, >> MPIdata%rank-1, MPIdata%rank, MPI_COMM_WORLD, >> *send_request(MPIdata%rank)*, MPIdata%iErr) >> >> This is what my code does. Problably, the use of send_request(:) as a >> vectror and the use of WAITALL is not correct, I am right? >> >> what do you suggest? >> >> Thanks a lot, >> Diego >> >> >> Diego >> >> >> On 30 September 2015 at 12:42, Jeff Squyres (jsquyres) < >> jsquy...@cisco.com> wrote: >> >>> Put differently: >>> >>> - You have an array of N requests >>> - If you're only filling up M of them (where N<M) >>> - And then you pass the whole array of size N to MPI >>> - Then N-M of them will have garbage values (unless you initialize them >>> to MPI_REQUEST_NULL) >>> - And MPI's behavior with garbage values will be unpredictable / >>> undefined >>> >>> You can either pass M (i.e., the number of requests that you have >>> *actually* filled) to MPI, or you can ensure that the N-M unused requests >>> in the array are filled with MPI_REQUEST_NULL (which MPI_WAITANY and >>> friends will safely ignore). One way of doing the latter is initializing >>> the entire array with MPI_REQUEST_NULL and then only filling in the M >>> entries with real requests. >>> >>> It seems much simpler / faster to just pass in M to MPI_WAITANY (any >>> friends), not N. >>> >>> >>> > On Sep 30, 2015, at 3:43 AM, Diego Avesani <diego.aves...@gmail.com> >>> wrote: >>> > >>> > Dear Gilles, Dear All, >>> > >>> > What do you mean that the array of requests has to be initialize via >>> MPI_Isend or MPI_Irecv? >>> > >>> > In my code I use three times MPI_Isend and MPI_Irecv so I have a >>> send_request(3). According to this, do I have to use MPI_REQUEST_NULL? >>> > >>> > In the meantime I check my code >>> > >>> > Thanks >>> > >>> > Diego >>> > >>> > >>> > On 29 September 2015 at 16:33, Gilles Gouaillardet < >>> gilles.gouaillar...@gmail.com> wrote: >>> > Diego, >>> > >>> > if you invoke MPI_Waitall on three requests, and some of them have not >>> been initialized >>> > (manually, or via MPI_Isend or MPI_Irecv), then the behavior of your >>> program is undetermined. >>> > >>> > if you want to use array of requests (because it make the program >>> simple) but you know not all of them are actually used, then you have to >>> initialize them with MPI_REQUEST_NULL >>> > (it might be zero on ompi, but you cannot take this for granted) >>> > >>> > Cheers, >>> > >>> > Gilles >>> > >>> > >>> > On Tuesday, September 29, 2015, Diego Avesani <diego.aves...@gmail.com> >>> wrote: >>> > dear Jeff, dear all, >>> > I have notice that if I initialize the variables, I do not have the >>> error anymore: >>> > ! >>> > ALLOCATE(SEND_REQUEST(nMsg),RECV_REQUEST(nMsg)) >>> > SEND_REQUEST=0 >>> > RECV_REQUEST=0 >>> > ! >>> > >>> > Could you please explain me why? >>> > Thanks >>> > >>> > >>> > Diego >>> > >>> > >>> > On 29 September 2015 at 16:08, Diego Avesani <diego.aves...@gmail.com> >>> wrote: >>> > Dear Jeff, Dear all, >>> > the code is very long, here something. I hope that this could help. >>> > >>> > What do you think? >>> > >>> > SUBROUTINE MATOPQN >>> > USE VARS_COMMON,ONLY:COMM_CART,send_messageR,recv_messageL,nMsg >>> > USE MPI >>> > INTEGER :: send_request(nMsg), recv_request(nMsg) >>> > INTEGER :: >>> send_status_list(MPI_STATUS_SIZE,nMsg),recv_status_list(MPI_STATUS_SIZE,nMsg) >>> > >>> > !send message to right CPU >>> > IF(MPIdata%rank.NE.MPIdata%nCPU-1)THEN >>> > MsgLength = MPIdata%jmaxN >>> > DO icount=1,MPIdata%jmaxN >>> > iNode = MPIdata%nodeList2right(icount) >>> > send_messageR(icount) = RIS_2(iNode) >>> > ENDDO >>> > >>> > CALL MPI_ISEND(send_messageR, MsgLength, MPI_DOUBLE_COMPLEX, >>> MPIdata%rank+1, MPIdata%rank+1, MPI_COMM_WORLD, >>> send_request(MPIdata%rank+1), MPIdata%iErr) >>> > >>> > ENDIF >>> > ! >>> > >>> > >>> > !recive message FROM left CPU >>> > IF(MPIdata%rank.NE.0)THEN >>> > MsgLength = MPIdata%jmaxN >>> > >>> > CALL MPI_IRECV(recv_messageL, MsgLength, MPI_DOUBLE_COMPLEX, >>> MPIdata%rank-1, MPIdata%rank, MPI_COMM_WORLD, recv_request(MPIdata%rank), >>> MPIdata%iErr) >>> > >>> > write(*,*) MPIdata%rank-1 >>> > ENDIF >>> > ! >>> > ! >>> > CALL MPI_WAITALL(nMsg,send_request,send_status_list,MPIdata%iErr) >>> > CALL MPI_WAITALL(nMsg,recv_request,recv_status_list,MPIdata%iErr) >>> > >>> > Diego >>> > >>> > >>> > On 29 September 2015 at 00:15, Jeff Squyres (jsquyres) < >>> jsquy...@cisco.com> wrote: >>> > Can you send a small reproducer program? >>> > >>> > > On Sep 28, 2015, at 4:45 PM, Diego Avesani <diego.aves...@gmail.com> >>> wrote: >>> > > >>> > > Dear all, >>> > > >>> > > I have to use a send_request in a MPI_WAITALL. >>> > > Here the strange things: >>> > > >>> > > If I use at the begging of the SUBROUTINE: >>> > > >>> > > INTEGER :: send_request(3), recv_request(3) >>> > > >>> > > I have no problem, but if I use >>> > > >>> > > USE COMONVARS,ONLY : nMsg >>> > > with nMsg=3 >>> > > >>> > > and after that I declare >>> > > >>> > > INTEGER :: send_request(nMsg), recv_request(nMsg), I get the >>> following error: >>> > > >>> > > [Lap] *** An error occurred in MPI_Waitall >>> > > [Lap] *** reported by process [139726485585921,0] >>> > > [Lap] *** on communicator MPI_COMM_WORLD >>> > > [Lap] *** MPI_ERR_REQUEST: invalid request >>> > > [Lap] *** MPI_ERRORS_ARE_FATAL (processes in this communicator will >>> now abort, >>> > > [Lap] *** and potentially your MPI job) >>> > > forrtl: error (78): process killed (SIGTERM) >>> > > >>> > > Someone could please explain to me where I am wrong? >>> > > >>> > > Thanks >>> > > >>> > > Diego >>> > > >>> > > _______________________________________________ >>> > > users mailing list >>> > > us...@open-mpi.org >>> > > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users >>> > > Link to this post: >>> http://www.open-mpi.org/community/lists/users/2015/09/27703.php >>> > >>> > >>> > -- >>> > Jeff Squyres >>> > jsquy...@cisco.com >>> > For corporate legal information go to: >>> http://www.cisco.com/web/about/doing_business/legal/cri/ >>> > >>> > _______________________________________________ >>> > users mailing list >>> > us...@open-mpi.org >>> > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users >>> > Link to this post: >>> http://www.open-mpi.org/community/lists/users/2015/09/27704.php >>> > >>> > >>> > >>> > _______________________________________________ >>> > users mailing list >>> > us...@open-mpi.org >>> > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users >>> > Link to this post: >>> http://www.open-mpi.org/community/lists/users/2015/09/27710.php >>> > >>> > _______________________________________________ >>> > users mailing list >>> > us...@open-mpi.org >>> > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users >>> > Link to this post: >>> http://www.open-mpi.org/community/lists/users/2015/09/27721.php >>> >>> >>> -- >>> Jeff Squyres >>> jsquy...@cisco.com >>> For corporate legal information go to: >>> http://www.cisco.com/web/about/doing_business/legal/cri/ >>> >>> _______________________________________________ >>> users mailing list >>> us...@open-mpi.org >>> Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users >>> Link to this post: >>> http://www.open-mpi.org/community/lists/users/2015/09/27727.php >>> >> >> > _______________________________________________ > users mailing list > us...@open-mpi.org > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users > Link to this post: > http://www.open-mpi.org/community/lists/users/2015/09/27742.php >
