MATLAB: Problem passing large array between matlab and mex function

fortranlarge arraymex

[EDIT: 20110523 19:35 CDT – reformat – WDR]
On 64-bit Windows 7 and 64-bit matlab, I have the following problem. When I pass a 2D array of type single (float32) and size (43500, 29200) from matlab to a mex function, only the first 196458176 values are passed to the mex function correctly. The same problem occurred when I passed a 2D array of type single and size (43500, 29200) from the mex function to matlab. The mex function is written in Fortran and the code was compiled by the Intel 64 Fortran compiler XE version 12.0.4.196 Build 20110427.
I can send you the Fortran code (io_64bit.f) for the mex function. I test the mex function by the following script:
nC = 43500;
nR = 29200;
din = ones(nC, nR, 'single');
[dout1, dout2] = io_64bit(din);
sdin   = sum(sum( int32(din) ));
sdout1 = sum(sum( int32(dout1) ));
sdout2 = sum(sum( int32(dout2) ));
If all goes well, sdout1 = sdin = – sdout2 = 1270200000 (= nC * nR)
Following is the Fortran code:
c***********************************************************************
c
c     Check fidelity of large array passed from Matlab to mex function
c     and vice versa.
c
c     [dout1, dout2] = io_64bit(din)
c
c***********************************************************************
c
c     Original: 18 May 2011                Final: 18 May 2011
c
c***********************************************************************
      subroutine mexFunction(nlhs, plhs, nrhs, prhs)
      implicit none
        integer*4    nlhs, nrhs
  c     <-----------------------------------------------------------------
  c     For 32-bit OS, change following to integer*4
  c     --------------------------------------------
        integer*8    plhs(*), prhs(*)
        integer*8    mxGetCell, mxGetM, mxGetN, mxGetPr
        integer*8    mxGetNumberOfElements, mxClassIDFromClassName
        integer*8    mxCreateNumericArray, mxCreateNumericMatrix
        integer*8    mxIsInt8, mxIsInt32, mxIsSingle
        integer*8    mexPrintf
        integer*8    nCol, nRow, din_p, dout1_p, dout2_p
        integer*8    n, ClassID, ComplexFlag
  c     ----------------------------------------------------------------->
        character (len = 48) eMsg
        integer    i, iStatus
        real       xmin, xmax
        real,      allocatable :: din(:,:)
        logical, parameter :: lDebug = .true.
c     ------------------------------------------------------------------
      if(nrhs /= 1) call mexerrmsgtxt('1 input argument is required')
      if(nlhs /= 2) call mexerrmsgtxt('2 outputs are produced')
        nCol = mxGetM(prhs(1))
        nRow = mxGetN(prhs(1))
        n = mxGetNumberOfElements(prhs(1))
        if(lDebug) then
           open(1,file='mex_io.log',status='unknown')
           write(1,*) nCol, nRow, n
        endif
        if(n /= nCol*nRow) then
           call mexErrMsgTxt('Cannot determine size of 2D array dem')
        endif
c     -------------------------------- Check inputs are of correct types
      eMsg = 'Argument x must be of type single / float32'
      do i=1, 1
         if(mxIsSingle(prhs(i)) == 0) then
            write(eMsg(10:10),'(i1)') i
            call mexErrMsgTxt(eMsg)
         endif
      enddo
c     -------------------------------- Allocate memory and setup pointer
      allocate(din(nCol,nRow),stat=iStatus)
      call check_allocation(iStatus, 'din')
        din = 0.0
        if(lDebug) write(1,*) 'Done memory allocation'
        din_p    = mxGetPr(prhs(1))
        if(lDebug) write(1,*) 'Done pointer ', din_p
c     -------------------------------------------- Copy data from Matlab
      call mxCopyPtrToReal4(din_p, din, n)
        if(lDebug) then
           write(1,*) 'Done copy ptr to real'
           call minmax(n, din, xmin, xmax)
           write(1,*) xmin, xmax
        endif
c     ------------------------------ Create output matrix of type single
      ClassID = mxClassIDFromClassName('single')
      ComplexFlag = 0
        plhs(1) = mxCreateNumericMatrix(nCol, nRow, ClassID, ComplexFlag)
        plhs(2) = mxCreateNumericMatrix(nCol, nRow, ClassID, ComplexFlag)
        dout1_p  = mxGetPr(plhs(1))
        dout2_p  = mxGetPr(plhs(2))
        if(lDebug) then
           write(1,*) ClassID
           close(1)
        endif
c     -------------------------------------------- Copy data 1 to Matlab
      call mxCopyReal4ToPtr(din, dout1_p, n)
c     -------------------------------------------- Copy data 2 to Matlab
      din = -1.0
      call mxCopyReal4ToPtr(din, dout2_p, n)
        deallocate(din)
        return
        end subroutine mexFunction
  c
  c=======================================================================
  c
        subroutine minmax(n, x, xmin, xmax)
        integer*8 n
        real xmin, xmax, x(n)
        integer i, ix, m
        xmin = huge(xmin)
        xmax = -xmin
        m = 0
        do i=1, n
           xmin = min(xmin, x(i))
           xmax = max(xmax, x(i))
           if(x(i) /= 0.0) ix = i
           if(x(i) == 0.0) m = m + 1
        enddo
c     ------------------------------------------------------------------
c     ix = no of values passed from Matlab correctly
c
c     m  = no of no-values from Matlab
c
c     (n - m) should = ix
c
c     ------------------------------------------------------------------
      write(1,*) ix, m, n - m
        return
        end subroutine minmax
  c
  c=======================================================================
  c
        subroutine check_allocation(iStatus, name)
        integer        iStatus
        character*(*)  name
        if(iStatus /= 0) then
           call mexErrMsgTxt('Cannot allocate memory for array '//name)
           stop
        endif
        return
        end subroutine check_allocation

Best Answer

Your FORTRAN code is missing:
#include "fintrf.h"
At the beginning of the file. This header is needed when using -largeArrayDims because it it responsible for switching which mx* functions are called. See the standard mex documentation and this solution be sure to read the faq that is linked to at the end of solution. The last section of the text faq has useful FORTRAN information.
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