!Homework 5
!Programmer: Chad Brewbaker
!Email address: crb002@iastate.edu
!Date: Febuary 16, 2004
!Machine used: hpc-class.iastate.edu (Intel Xenon cluster)
!Compiler options used:

program
implicit none
integer, parameter :: n=3
real*8,dimension(:),allocatable::B
real*8::A(1:n)
include "mpif.h"
integer::i,j,ierror,p,rank,status(mpi_status_size)
call mpi_init(ierror)
call mpi_comm_size(mpi_comm_world,p,ierror)
call mpi_comm_rank(mpi_comm_world,rank,ierror)

call random_number(A)
A=A+rank
print *,  'On processor',rank,'A=',A
if(rank==0)then
   allocate(B(1:n))
   B=A
   do i=1,p-1
      call MPI_Recv(A(1),n,MPI_REAL8,MPI_ANY_SOURCE,1,MPI_COMM_WORLD,status,ierror)
      do j=1,n
         B(j)=A(j)+B(j)
      enddo
   enddo
   print *,'Final result is B=',B
   deallocate(B)
endif
if(rank.ne.0)then
   call MPI_Send(A(1),n,MPI_REAL8,0,1,MPI_COMM_WORLD,ierror)
endif
call MPI_Finalize(ierror)
end program

!!$vincent% mpirun -np 4 hw5.exe
!!$ On processor           1 A=   1.77326712988589        1.82325123434867
!!$   1.14812062030844
!!$ On processor           2 A=   2.77326712988589        2.82325123434867
!!$   2.14812062030844
!!$ On processor           3 A=   3.77326712988589        3.82325123434867
!!$ On processor           0 A=  0.773267129885890       0.823251234348674
!!$  0.148120620308437
!!$ Final result is B=   9.09306851954356        9.29300493739470
!!$   6.59248248123375
!!$   3.14812062030844
!!$vincent%