Compiling A Mexfile using R CMD SHLIB - r

Question

I am trying to import a number of Fortran 90 codes into R for a project. They were initially written with a mex (matlab integration of Fortran routines) type compilation in mind. This is what one of the codes look like:
# include <fintrf.h>
subroutine mexFunction(nlhs, plhs, nrhs, prhs)
!--------------------------------------------------------------
! MEX file for VFI3FCN routine
!
! log M_{t,t+1} = log \beta + gamma (x_t - x_{t+1})
! gamma = gamA + gamB (x_t - xbar)
!
!--------------------------------------------------------------
implicit none
mwPointer plhs(*), prhs(*)
integer nlhs, nrhs
mwPointer mxGetM, mxGetPr, mxCreateDoubleMatrix
mwPointer nk, nkp, nz, nx, nh
mwSize col_hxz, col_hz, col_xz
! check for proper number of arguments.
if(nrhs .ne. 31) then
call mexErrMsgTxt('31 input variables required.')
elseif(nlhs .ne. 4) then
call mexErrMsgTxt('4 output variables required.')
endif
! get the size of the input array.
nk = mxGetM(prhs(5))
nx = mxGetM(prhs(7))
nz = mxGetM(prhs(11))
nh = mxGetM(prhs(14))
nkp = mxGetM(prhs(16))
col_hxz = nx*nz*nh
col_xz = nx*nz
col_hz = nz*nh
! create matrix for the return arguments.
plhs(1) = mxCreateDoubleMatrix(nk, col_hxz, 0)
plhs(2) = mxCreateDoubleMatrix(nk, col_hxz, 0)
plhs(3) = mxCreateDoubleMatrix(nk, col_hxz, 0)
plhs(4) = mxCreateDoubleMatrix(nk, col_hxz, 0)
call vfi3fcnIEccB(%val(mxGetPr(plhs(1))), nkp)
return
end
subroutine vfi3fcnIEccB(optK, V, I, div, & ! output variables
alp1, alp2, alp3, V0, k, nk, x, xbar, nx, Qx, z, nz, Qz, h, nh, kp, &
alpha, beta, delta, f, gamA, gamB, gP, gN, istar, kmin, kmtrx, ksubm, hmtrx, xmtrx, zmtrx, &
nkp, col_hxz, col_xz, col_hz)
use ifwin
implicit none
! specify input and output variables
integer, intent(in) :: nk, nkp, nx, nz, nh, col_hxz, col_xz, col_hz
real*8, intent(out) :: V(nk, col_hxz), optK(nk, col_hxz), I(nk, col_hxz), div(nk, col_hxz)
real*8, intent(in) :: V0(nk, col_hxz), k(nk), kp(nkp), x(nx), z(nz), Qx(nx, nx), Qz(nz, nz), h(nh)
real*8, intent(in) :: alp1, alp2, alp3, xbar, kmin, alpha, gP, gN, beta, delta, gamA, gamB, f, istar
real*8, intent(in) :: kmtrx(nk, col_hxz), ksubm(nk, col_hz), zmtrx(nk, col_hxz), xmtrx(nk, col_hxz), hmtrx(nk, col_hxz)
! specify intermediate variables
real*8 :: Res(nk, col_hxz), Obj(nk, col_hxz), optKold(nk, col_hxz), Vold(nk, col_hxz), tmpEMV(nkp, col_hz), tmpI(nkp), &
tmpObj(nkp, col_hz), tmpA(nk, col_hxz), tmpQ(nx*nh, nh), detM(nx), stoM(nx), g(nkp), tmpInd(nh, nz)
real*8 :: Qh(nh, nh, nx), Qxh(nx*nh, nx*nh), Qzxh(col_hxz, col_hxz)
real*8 :: hp, d(nh), errK, errV, T1, lapse
integer :: ix, ih, iter, optJ(col_hz), ik, iz, ind(nh, col_xz), subindex(nx, col_hz)
logical*4 :: statConsole
! construct the transition matrix for kh --- there are nx number of these transition matrix: 3-d
Qh = 0.0
do ix = 1, nx
do ih = 1, nh
! compute the predicted next period kh
hp = alp1 + alp2*h(ih) + alp3*(x(ix) - xbar)
! construct transition probability vector
d = abs(h - hp) + 1D-32
Qh(:, ih, ix) = (1/d)/sum(1/d)
end do
end do
! construct the compound transition matrix over (z x h) space
! compound the (x h) space
Qxh = 0.0
do ix = 1, nx
call kron(tmpQ, Qx(:, ix), Qh(:, :, ix), nx, 1, nh, nh)
Qxh(:, (ix - 1)*nh + 1 : ix*nh) = tmpQ
end do
! compound the (z x h) space: h changes the faster, followed by x, and z changes the slowest
call kron(Qzxh, Qz, Qxh, nz, nz, nx*nh, nx*nh)
! available funds for the firm
Res = dexp(xmtrx + zmtrx + hmtrx)*(kmtrx**alpha) + (1 - delta)*kmtrx - f
! initializing
Obj = 0.0
optK = 0.0
optKold = optK + 1.0
Vold = V0
! Some Intermediate Variables Used in Stochastic Discount Factor
detM = beta*dexp((gamA - gamB*xbar)*x + gamB*x**2)
stoM = -(gamA - gamB*xbar + gamB*x)
! Intermediate index vector to facilitate submatrix extracting
ind = reshape((/1 : col_hxz : 1/), (/nh, col_xz/))
do ix = 1, nx
tmpInd = ind(:, ix : col_xz : nx)
do iz = 1, nz
subindex(ix, (iz - 1)*nh + 1 : iz*nh) = tmpInd(:, iz)
end do
end do
! start iterations
errK = 1.0
errV = 1.0
iter = 0
T1 = secnds(0.0)
do
if (errV <= 1D-3 .AND. errK <= 1D-8) then
exit
else
iter = iter + 1
do ix = 1, nx
! next period value function by linear interpolation: nkp by nz*nh matrix
call interp1(tmpEMV, k, detM(ix)*(matmul(dexp(stoM(ix)*xmtrx)*Vold, Qzxh(:, subindex(ix, :)))) - ksubm, kp, &
nk, nkp, col_hz)
! maximize the right-hand size of Bellman equation on EACH grid point of capital stock
do ik = 1, nk
! with istar tmpI is no longer investment but a linear transformation of that
tmpI = (kp - (1.0 - delta)*k(ik))/k(ik) - istar
where (tmpI >= 0.0)
g = gP
elsewhere
g = gN
end where
tmpObj = tmpEMV - spread((g/2.0)*(tmpI**2)*k(ik), 2, col_hz)
! direct discrete maximization
Obj(ik, subindex(ix, :)) = maxval(tmpObj, 1)
optJ = maxloc(tmpObj, 1)
optK(ik, subindex(ix, :)) = kp(optJ)
end do
end do
! update value function and impose limited liability condition
V = max(Res + Obj, 1D-16)
! convergence criterion
errK = maxval(abs(optK - optKold))
errV = maxval(abs(V - Vold))
! revise Initial Guess
Vold = V
optKold = optK
! visual
if (modulo(iter, 50) == 0) then
lapse = secnds(T1)
statConsole = AllocConsole()
print "(a, f10.7, a, f10.7, a, f8.1, a)", " errV:", errV, " errK:", errK, " Time:", lapse, "s"
end if
end if
end do
! visual check on errors
lapse = secnds(T1)
statConsole = AllocConsole()
print "(a, f10.7, a, f10.7, a, f8.1, a)", " errV:", errV, " errK:", errK, " Time:", lapse, "s"
! optimal investment and dividend
I = optK - (1.0 - delta)*kmtrx
tmpA = I/kmtrx - istar
where (tmpA >= 0)
div = Res - optK - (gP/2.0)*(tmpA**2)*kmtrx
elsewhere
div = Res - optK - (gN/2.0)*(tmpA**2)*kmtrx
end where
return
end
subroutine interp1(v, x, y, u, m, n, col)
!-------------------------------------------------------------------------------------------------------
! Linear interpolation routine similar to interp1 with 'linear' as method parameter in Matlab
!
! OUTPUT:
! v - function values on non-grid points (n by col matrix)
!
! INPUT:
! x - grid (m by one vector)
! y - function defined on the grid x (m by col matrix)
! u - non-grid points on which y(x) is to be interpolated (n by one vector)
! m - length of x and y vectors
! n - length of u and v vectors
! col - number of columns of v and y matrices
!
! Four ways to pass array arguments:
! 1. Use explicit-shape arrays and pass the dimension as an argument(most efficient)
! 2. Use assumed-shape arrays and use interface to call external subroutine
! 3. Use assumed-shape arrays and make subroutine internal by using "contains"
! 4. Use assumed-shape arrays and put interface in a module then use module
!
! This subroutine is equavilent to the following matlab call
! v = interp1(x, y, u, 'linear', 'extrap') with x (m by 1), y (m by col), u (n by 1), and v (n by col)
!------------------------------------------------------------------------------------------------------
implicit none
integer :: m, n, col, i, j
real*8, intent(out) :: v(n, col)
real*8, intent(in) :: x(m), y(m, col), u(n)
real*8 :: prob
do i = 1, n
if (u(i) < x(1)) then
! extrapolation to the left
v(i, :) = y(1, :) - (y(2, :) - y(1, :)) * ((x(1) - u(i))/(x(2) - x(1)))
else if (u(i) > x(m)) then
! extrapolation to the right
v(i, :) = y(m, :) + (y(m, :) - y(m-1, :)) * ((u(i) - x(m))/(x(m) - x(m-1)))
else
! interpolation
! find the j such that x(j) <= u(i) < x(j+1)
call bisection(x, u(i), m, j)
prob = (u(i) - x(j))/(x(j+1) - x(j))
v(i, :) = y(j, :)*(1 - prob) + y(j+1, :)*prob
end if
end do
end subroutine interp1
subroutine bisection(list, element, m, k)
!--------------------------------------------------------------------------------
! find index k in list such that (list(k) <= element < list(k+1)
!--------------------------------------------------------------------------------
implicit none
integer*4 :: m, k, first, last, half
real*8 :: list(m), element
first = 1
last = m
do
if (first == (last-1)) exit
half = (first + last)/2
if ( element < list(half) ) then
! discard second half
last = half
else
! discard first half
first = half
end if
end do
k = first
end subroutine bisection
subroutine kron(K, A, B, rowA, colA, rowB, colB)
!--------------------------------------------------------------------------------
! Perform K = kron(A, B); translated directly from kron.m
!
! OUTPUT:
! K -- rowA*rowB by colA*colB matrix
!
! INPUT:
! A -- rowA by colA matrix
! B -- rowB by colB matrix
! rowA, colA, rowB, colB -- integers containing shape information
!--------------------------------------------------------------------------------
implicit none
integer, intent(in) :: rowA, colA, rowB, colB
real*8, intent(in) :: A(rowA, colA), B(rowB, colB)
real*8, intent(out) :: K(rowA*rowB, colA*colB)
integer :: t1(rowA*rowB), t2(colA*colB), i, ia(rowA*rowB), ja(colA*colB), ib(rowA*rowB), jb(colA*colB)
t1 = (/ (i, i = 0, (rowA*rowB - 1)) /)
ia = int(t1/rowB) + 1
ib = mod(t1, rowB) + 1
t2 = (/ (i, i = 0, (colA*colB - 1)) /)
ja = int(t2/colB) + 1
jb = mod(t2, colB) + 1
K = A(ia, ja)*B(ib, jb)
end subroutine kron
My initial plan was to remove the mexFunction subroutine and compile the main Fortran subroutines using the R CMD SHLIB command but then I run into the Rtools compiler not knowing where to find the ifwin library even though I have the library in my intel fortran compiler folder.
So my first question is:
1) Is there a way for me to tell rtools where to find the ifwin library and any other library I need to include? Or is there a way to include the dependency libraries in the R CMD SHLIB command so the compiler can find the necessary libraries and compile?
2) If the answer to two is no, can I some how use the compiled version from Matlab in R. I can compile the file as is in matlab using the mex Zhang_4.f90 command with no errors.
3) Is there a way of setting up an environment in Visual Studio 2015 so I can compile Fortran subroutines for use in R using the Intel compiler?
When I take out the mexFunction subroutine and try compiling the rest of the code, I get the following error:
D:\SS_Programming\Fortran>R CMD SHLIB Zhang_4.f90
c:/Rtools/mingw_64/bin/gfortran -O2 -mtune=core2 -c Zhang_4.f90 -o
Zhang_4.o
Zhang_4.f90:6.4:
use ifwin
1
Fatal Error: Can't open module file 'ifwin.mod' for reading at (1): No
such file or directory
make: *** [Zhang_4.o] Error 1
Warning message:
running command 'make -f "C:/PROGRA~1/R/R-34~1.2/etc/x64/Makeconf" -f
"C:/PROGRA~1/R/R-34~1.2/share/make/winshlib.mk"
SHLIB_LDFLAGS='$(SHLIB_FCLDFLAGS)' SHLIB_LD='$(SHLIB_FCLD)'
SHLIB="Zhang_4.dll" SHLIB_LIBADD='$(FCLIBS)' WIN=64 TCLBIN=64
OBJECTS="Zhang_4.o"' had status 2

Answer 1

I don't think there is any other way then rewrite the code to not use IFWIN. Unless you manage to use Intel Fortran for R (that might require recompiling the whole R distribution...). Matlab is tied to Intel Fortran, that's why the code worked there.
You have to adjust the code anyway, you cannot use it as it stands.
Just get rid of the AllocConsole() calls and the print statements. You will need to use the R routines to print to console. See https://cran.r-project.org/doc/manuals/R-exts.html#Printing-from-FORTRAN