User`s manual

Examples of Fortran MEX-Files

3-17

Passing Matrices

In MATLAB, you can pass matrices into and out of MEX-files written in

Fortran. You can manipulate the MATLAB arrays by using

mxGetPr and

mxGetPi to assign pointers to the real and imaginary parts of the data stored

in the MATLAB arrays. You can create new MATLAB arrays from within your

MEX-file by using

mxCreateFull.

This example takes a real 2-by-3 matrix and squares each element.

C--------------------------------------------------------------

C matsq.f

C Squares the input matrix

C This is a MEX-file for MATLAB.

C $Revision: 1.12 $

C--------------------------------------------------------------

subroutine matsq(y, x, m, n)

real*8 x(m,n), y(m,n)

integer m, n

do 20 i=1,m

do 10 j=1,n

y(i,j)= x(i,j)**2

10 continue

20 continue

return

end

This is the gateway routine that calls the computational subroutine.

subroutine mexFunction(nlhs, plhs, nrhs, prhs)

C--------------------------------------------------------------

C (pointer) Replace integer by integer*8 on the DEC Alpha

C platform.

integer plhs(*), prhs(*)

integer mxCreateFull, mxGetPr