[R-sig-hpc] using MPI fortran without the library(Rmpi)

[Hodgess, Erin]

Hello everyone:

I'm experiment with some toy code.  I was looking to see if I can write a program in Fortran with MPI to work in conjunction with R without the Rmpi library.  Here is the Fortran code:

      subroutine integcR(np,integral)
      implicit none
      include '/usr/local/include/mpif.h'
      integer rank,size,ierror,tag,status(MPI_STATUS_SIZE),i,np
      double precision :: integral,x, total_t
      double precision :: numres,edif
      double precision, PARAMETER :: x_lower_bound = 0.0,x_upper_bound = 1.0
      integer, PARAMETER :: nSteps = 100000000
      double precision, PARAMETER :: dx = (x_upper_bound - x_lower_bound)/nSteps
      double precision :: analy
      integer :: iMin,iMax
      call MPI_INIT(ierror)
      call MPI_COMM_SIZE(MPI_COMM_WORLD,size,ierror)
      call MPI_COMM_RANK(MPI_COMM_WORLD,rank,ierror)
      integral = 0.0
      x = 0.0
      total_t = 0.0
      iMin = INT((rank * real(nSteps,kind=8))/real(size,kind=8))
      iMax = INT(((rank+1) * real(nSteps,kind=8))/real(size,kind=8))
       do i = iMin,(iMax-1)
          x = x_lower_bound + dx*(real(i,kind=8)+0.5)
          integral = integral + (x**np)*dx
       end do

              call MPI_REDUCE(integral,total_t,1,MPI_DOUBLE_PRECISION,MPI_SUM,0,MPI_COMM_WORLD,ierror)

       numres = total_t

      call MPI_FINALIZE(ierror)
      end

And the R function is:
nb <- 4
if(!is.loaded("integcR"))dyn.load("integcR.so")
print("is")
print(is.loaded("integcR"))
gtot <- 0.0
integral <- 0.0

xplanet <- .Fortran("integcR",np=as.integer(nb),
        integral=as.numeric(integral))$numres
print("planet")
print(xplanet)

Finally, the Batch file is:
#!/bin/bash
mpif90 -g -O2 -fPIC  integcR.f90 -shared -o integcR.so

mpirun -np 4 Rscript testR10.R  >out10.txt


When I run it, the Fortran program shows that it is not loaded.

Is there anything obvious that I'm doing wrong, please?  Or can this not be done, please?

Thanks in advance,
Sincerely,
Erin








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