Dear all,
thanks thank a lot, I am learning a lot.
I have written a simple program that send vectors of integers from a CPU to
another.
The program is written (at least for now) for 4 CPU.
The program is quite simple:
Each CPU knows how many data has to send to the other CPUs. This info is
than send to the other CPUS. In this way each CPU knows how may data has to
receive from other CPUs.
This part of the program works.
The problem is in the second part.
In the second part, each processor sends a vector of integer to the other
processor. The size is given and each CPU knows the size of the incoming
vector form the first part of the program.
In this second part the program fails and I do not know why.
In the attachment you can find the program. Could you please help me.
Problably I didn't understand properly the ISEND and IRECV subroutine.
Thanks again
Diego
MODULE MOD_PRECISION
integer, parameter :: dp = selected_real_kind(p=16)
ENDMODULE MOD_PRECISION
PROGRAM TEST
USE MOD_PRECISION
USE MPI
IMPLICIT NONE
!
INTEGER :: iCPU,icount,iTag,ip,sendcount,sendrecv,i
!
TYPE tMPI
INTEGER :: myrank, nCPU, iErr, status
END TYPE tMPI
!
INTEGER, ALLOCATABLE,DIMENSION(:) :: Ndata2send
INTEGER, ALLOCATABLE,DIMENSION(:) :: Ndata2recv
INTEGER, ALLOCATABLE,DIMENSION(:) :: DATASEND
INTEGER, ALLOCATABLE,DIMENSION(:) :: DATARECV
!
INTEGER :: send_request ( 3)
INTEGER :: recv_request ( 3)
INTEGER :: send_status_list (MPI_STATUS_SIZE,3)
INTEGER :: recv_status_list (MPI_STATUS_SIZE,3)
!
TYPE(tMPI) :: MPIdata
CALL MPI_INIT(MPIdata%iErr)
CALL MPI_COMM_RANK(MPI_COMM_WORLD, MPIdata%myrank, MPIdata%iErr)
CALL MPI_COMM_SIZE(MPI_COMM_WORLD, MPIdata%nCPU, MPIdata%iErr)
!
ALLOCATE(Ndata2send(0:MPIdata%nCPU-1))
ALLOCATE(Ndata2recv(0:MPIdata%nCPU-1))
!
Ndata2send=0
Ndata2recv=0
!
IF(MPIdata%myrank==0)THEN
Ndata2send(0)=0
Ndata2send(1)=10
Ndata2send(2)=10
Ndata2send(3)=16
ENDIF
IF(MPIdata%myrank==1)THEN
Ndata2send(0)=13
Ndata2send(1)=0
Ndata2send(2)=16
Ndata2send(3)=16
ENDIF
IF(MPIdata%myrank==2)THEN
Ndata2send(0)=13
Ndata2send(1)=16
Ndata2send(2)=0
Ndata2send(3)=16
ENDIF
IF(MPIdata%myrank==3)THEN
Ndata2send(0)=16
Ndata2send(1)=16
Ndata2send(2)=16
Ndata2send(3)=0
ENDIF
!
CALL MPI_BARRIER(MPI_COMM_WORLD, MPIdata%iErr)
icount=1
DO iCPU=0,MPIdata%nCPU-1
IF(iCPU.NE.MPIdata%myrank)THEN
iTag=iCPU
CALL MPI_ISEND(Ndata2send(iCPU),1,MPI_INTEGER,iCPU,iTag,MPI_COMM_WORLD,send_request(icount),MPIdata%iErr)
icount=icount+1
ENDIF
ENDDO
!
icount=1
DO iCPU=0,MPIdata%nCPU-1
IF(iCPU.NE.MPIdata%myrank)THEN
iTag=MPIdata%myrank
CALL MPI_IRECV(Ndata2recv(iCPU),1,MPI_INTEGER,iCPU,iTag,MPI_COMM_WORLD,recv_request(icount),MPIdata%iErr)
icount=icount+1
ENDIF
ENDDO
!
CALL MPI_WAITALL(MPIdata%nCPU-1,send_request,send_status_list,MPIdata%iErr)
CALL MPI_WAITALL(MPIdata%nCPU-1,recv_request,recv_status_list,MPIdata%iErr)
!
!+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
!+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
!+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
!
sendcount=1
DO iCPU=0,MPIdata%nCPU-1
IF(MPIdata%myrank.NE.iCPU)THEN
!
ALLOCATE(DATASEND(Ndata2send(iCPU)))
!
DO ip=1,Ndata2send(iCPU)
DATASEND(ip) = ip
ENDDO
!
iTag=iCPU
CALL MPI_ISEND(DATASEND(:),Ndata2send(iCPU),MPI_INTEGER,iCPU,iTag,MPI_COMM_WORLD,send_request(icount),MPIdata%iErr)
sendcount=sendcount+1
DEALLOCATE(DATASEND)
!
ENDIF
ENDDO
!
!
CALL MPI_BARRIER(MPI_COMM_WORLD, MPIdata%iErr)
!
!
sendrecv=1
DO iCPU=0,MPIdata%nCPU-1
!
ALLOCATE(DATARECV(Ndata2send(iCPU)))
!
IF(MPIdata%myrank.NE.iCPU)THEN
iTag=MPIdata%myrank
CALL MPI_IRECV(DATARECV,Ndata2recv(iCPU),MPI_INTEGER,iCPU,iTag,MPI_COMM_WORLD,recv_request(sendrecv),MPIdata%iErr)
sendrecv=sendrecv+1
ENDIF
DO i=1,Ndata2recv(iCPU)
WRITE(*,*) DATARECV(i)
ENDDO
!
DEALLOCATE(DATARECV)
!
ENDDO
CALL MPI_WAITALL(MPIdata%nCPU-1,send_request,send_status_list,MPIdata%iErr)
CALL MPI_WAITALL(MPIdata%nCPU-1,recv_request,recv_status_list,MPIdata%iErr)
CALL MPI_Finalize(MPIdata%iErr)
ENDPROGRAM
