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POPassing functions in R as .Fortran arguments
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copied!<p>After spending some days already searching for something like this on the internet, I still couldn't manage to find anything describing this problem. Reading through the (otherwise quite recommendable) 'Writing R Extensions' dind't offer a solution as well. Thus, here's my most urgent question:</p> <p>Is it possible to pass functions (for simplicity's sake, assume a simple R function - in reality, the problem is even uglier) as function/subroutine parameters to Fortran via .Fortran(...) call - and if so, how?</p> <p>I wrote two simple functions in order to test this, first a Fortran subroutine (tailored to use the function I originally intended to pass, thus the kinda weird dimensions in the interface):</p> <pre><code>subroutine foo(o, x) implicit none interface subroutine o(t, y, param, f) double precision, intent(in) :: t double precision, dimension(58), intent(in) :: y, param double precision, dimension(22), intent(out) :: f end subroutine end interface double precision, dimension(22), intent(out) :: x double precision, dimension(58) :: yt, paramt integer :: i do i = 1, 58 yt(i) = rand(0) paramt(i) = rand(1) end do call o(dble(4.2), yt, paramt, x) end subroutine </code></pre> <p>and a simple R function to pass to the above function:</p> <pre><code>asdf <- function(a, s, d, f){x <- c(a, s, d, f)} </code></pre> <p>Calling <code>.Fortran("foo", asdf, vector(mode="numeric", length=22))</code> yields <code>Error: invalid mode (closure) to pass to Fortran (arg 1)</code> and passing "asdf" (as a string) results in a segfault, as the argument obviously doesn't fit the expected type (namely, a function).</p> <p>FYI, I don't expect the code to do anything meaningful (that would be the task of another function), I mainly would like to know, whether passing functions (or function pointers) from R is possible at all or wether I better give up on this approach instantly and look for something that might work.</p> <p>Thanks in advance,</p> <p>Dean</p>

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