Reputation: 7948
I'm trying to write an R package that calls a Fortran subroutine. I'm using Rstudio package template that creates a bunch of files and directories automatically.
In ./R/
I have a single file, Fpi.R
Fpi <- function(DARTS, ROUNDS) {
if (!is.loaded('Fpi')) {
dyn.load("./src/Fpi.so")
}
retvals <- .Fortran("pi", avepi = as.numeric(1), DARTS = as.integer(DARTS), ROUNDS = as.integer(ROUNDS))
return(retvals$avepi)
}
In ./src/
I have Fpi.f90
subroutine dboard(darts, dartsscore)
implicit none
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)
implicit none
double precision, intent(out) :: avepi
integer, intent(in) :: DARTS, ROUNDS
integer :: MASTER, rank, i, n
integer, allocatable :: seed(:)
double precision :: pi_est, homepi, pirecv, pisum
interface
subroutine dboard(darts, dartsscore)
implicit none
integer, intent(in) :: darts
double precision, intent(out) :: dartsscore
end subroutine dboard
end interface
! 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
I also have the generic DESCRIPTION and NAMESPACE files that rstudio generates.
I can build and load the library but when I try to use it I get this error:
> library(MyPi)
> Fpi(DARTS = 100, ROUNDS = 100)
Error in .Fortran("pi", avepi = as.numeric(1), DARTS = as.integer(DARTS), :
"pi" not resolved from current namespace (MyPi)
How can I fix this? Thanks!
Upvotes: 4
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