[R-pkg-devel] not resolved from current namespace error

[Ignacio Martinez]

I'm trying to create a package that uses a MPI Fortran module. I have a working
version <https://github.com/ignacio82/MyPi> of that package that uses a
Fortran module without MPI.

When I run the function `FMPIpi(DARTS = 5000, ROUNDS = 100, cores=2)` I get
the following errors:

> FMPIpi(DARTS = 5000, ROUNDS = 100, cores=2)
2 slaves are spawned successfully. 0 failed.
master (rank 0, comm 1) of size 3 is running on: 2d60fd60575b
slave1 (rank 1, comm 1) of size 3 is running on: 2d60fd60575b
slave2 (rank 2, comm 1) of size 3 is running on: 2d60fd60575b
Error in .Fortran("MPIpi", avepi = as.numeric(1), DARTS =
as.integer(DARTS),  :
 "mpipi" not resolved from current namespace (MyPi)

It looks like something is wrong in my NAMESPACE. This is what I have there:

export(Pibenchmark)
export(Fpi)
export(FMPIpi)
export(Rpi)
useDynLib(MyPi)
exportPattern("^[[:alpha:]]+")
This is my Fortran module:

Module Fortranpi
USE MPI
IMPLICIT NONE
contains
subroutine dboard(darts, dartsscore)
 integer, intent(in)                    :: darts
 double precision, intent(out)          :: dartsscore
 double precision                       :: x_coord, y_coord
 integer                                :: score, n

score = 0
do n = 1, darts
 call random_number(x_coord)
 call random_number(y_coord)

 if ((x_coord**2 + y_coord**2) <= 1.0d0) then
 score = score + 1
 end if
end do

dartsscore = 4.0d0*score/darts

end subroutine dboard

subroutine pi(avepi, DARTS, ROUNDS) bind(C, name="pi_")
 use, intrinsic                         :: iso_c_binding, only : c_double,
c_int
 real(c_double), intent(out)            ::  avepi
 integer(c_int), intent(in)             ::  DARTS, ROUNDS
 integer                                ::  MASTER, rank, i, n
 integer, allocatable                   ::  seed(:)
 double precision                       ::  pi_est, homepi, pirecv, pisum

! we set it to zero in the sequential run
rank = 0
! initialize the random number generator
! we make sure the seed is different for each task
call random_seed()
call random_seed(size = n)
allocate(seed(n))
seed = 12 + rank*11
call random_seed(put=seed(1:n))
deallocate(seed)

avepi = 0
do i = 0, ROUNDS-1
 call dboard(darts, pi_est)
 ! calculate the average value of pi over all iterations
 avepi = ((avepi*i) + pi_est)/(i + 1)
end do
end subroutine pi


subroutine MPIpi(avepi, DARTS, ROUNDS) bind(C, name="MPIpi_")
use, intrinsic                         :: iso_c_binding, only : c_double,
c_int
real(c_double), intent(out)            :: avepi
integer(c_int), intent(in)             :: DARTS, ROUNDS
integer                                :: i, n, mynpts, ierr, numprocs,
proc_num
integer, allocatable                   :: seed(:)
double precision                       :: pi_est, y, sumpi

 call mpi_init(ierr)
 call mpi_comm_size(MPI_COMM_WORLD, numprocs, ierr)
 call mpi_comm_rank(MPI_COMM_WORLD, proc_num, ierr)

 if (numprocs .eq. 0) then
mynpts = ROUNDS - (numprocs-1)*(ROUNDS/numprocs)
 else
mynpts = ROUNDS/numprocs
 endif

 ! initialize the random number generator
 ! we make sure the seed is different for each task
 call random_seed()
 call random_seed(size = n)
 allocate(seed(n))
 seed = 12 + proc_num*11
 call random_seed(put=seed(1:n))
 deallocate(seed)

 y=0.0d0
do i = 1, mynpts
call dboard(darts, pi_est)
y = y + pi_est
 end do

 call mpi_reduce(y, sumpi, 1, mpi_double_precision, mpi_sum, 0, &
 mpi_comm_world, ierr)
 if (proc_num==0) avepi = sumpi/ROUNDS
 call mpi_finalize(ierr)
end subroutine MPIpi

end module Fortranpi
and this is my R function

#'@export
FMPIpi <- function(DARTS, ROUNDS, cores) {
 Rmpi::mpi.spawn.Rslaves(nslaves=cores)
 retvals <- .Fortran("MPIpi", avepi = as.numeric(1), DARTS =
 as.integer(DARTS), ROUNDS =  as.integer(ROUNDS))
 return(retvals$avepi)
}

What am I doing wrong?

Thanks a lot!

Ignacio

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