HI, James,
I am testing Intel MPI on my computer. I do not know why the following MPI sample codes failed to run. after I made a minor revision on stoping message from sending from process 0 to iteself, then everything works well. Why is process 0 not allowed to send message to itself in Intel MPI and then receive it by itslef? I look forward to hearing from you. Thanks.
Dingjun
Please the original sample codes:
program vector
include 'mpif.h'
integer SIZE
parameter(SIZE=4)
integer numtasks, rank, source, dest, tag, i, ierr
real*4 a(0:SIZE-1,0:SIZE-1), b(0:SIZE-1)
integer stat(MPI_STATUS_SIZE), rowtype
C Fortran stores this array in column major order
data a /1.0, 2.0, 3.0, 4.0,
& 5.0, 6.0, 7.0, 8.0,
& 9.0, 10.0, 11.0, 12.0,
& 13.0, 14.0, 15.0, 16.0 /
call MPI_INIT(ierr)
call MPI_COMM_RANK(MPI_COMM_WORLD, rank, ierr)
call MPI_COMM_SIZE(MPI_COMM_WORLD, numtasks, ierr)
call MPI_TYPE_VECTOR(SIZE, 1, SIZE, MPI_REAL, rowtype, ierr)
call MPI_TYPE_COMMIT(rowtype, ierr)
tag = 1
if (numtasks .eq. SIZE) then
if (rank .eq. 0) then
do 10 i=0, numtasks-1
call MPI_SEND(a(i,0), 1, rowtype, i, tag,
& MPI_COMM_WORLD, ierr)
10 continue
endif
source = 0
call MPI_RECV(b, SIZE, MPI_REAL, source, tag,
& MPI_COMM_WORLD, stat, ierr)
print *, 'rank= ',rank,' b= ',b
else
print *, 'Must specify',SIZE,' processors. Terminating.'
endif
call MPI_TYPE_FREE(rowtype, ierr)
call MPI_FINALIZE(ierr)
end
The minor revisions are made for the above sample codes and please see the following codes:
program vector
include 'mpif.h'
integer SIZE
parameter(SIZE=4)
integer numtasks, rank, source, dest, tag, i,j, ierr
real*4 a(0:SIZE-1,0:SIZE-1), b(0:SIZE-1)
integer stat(MPI_STATUS_SIZE), rowtype,avalue
C Fortran stores this array in column major order
! data a /1.0, 2.0, 3.0, 4.0,
! & 5.0, 6.0, 7.0, 8.0,
! & 9.0, 10.0, 11.0, 12.0,
! & 13.0, 14.0, 15.0, 16.0 /
avalue=0
do i=0,3
doj=0,3
avalue= avalue+1
a(i,j)=avalue
end do
end do
call MPI_INIT(ierr)
call MPI_COMM_RANK(MPI_COMM_WORLD, rank, ierr)
call MPI_COMM_SIZE(MPI_COMM_WORLD, numtasks, ierr)
call MPI_TYPE_VECTOR(SIZE, 1, SIZE, MPI_REAL, rowtype, ierr)
callMPI_TYPE_COMMIT(rowtype, ierr)
tag = 1
if (numtasks .eq. SIZE) then
if (rank .eq. 0) then
do i=0,3
b(i)=a(0,i)
! array stored in column for Fortran
end do
print *,'rank= ',rank,' ', b
do i=1, numtasks-1
call MPI_SEND(a(i,0), 1, rowtype, i, tag,
& MPI_COMM_WORLD, ierr)
end do
endif
source = 0
if(rank.gt.0) then
call MPI_RECV(b, SIZE, MPI_REAL, source, tag,
& MPI_COMM_WORLD, stat, ierr)
print *, 'rank= ',rank,' b= ',b
endif
else
print *, 'Must specify',SIZE,' processors. Terminating.'
endif
call MPI_TYPE_FREE(rowtype, ierr)
call MPI_FINALIZE(ierr)
end
