Comments on: A Short MEX Tutorial and Demo

By: busy_bee

busy_bee — Sat, 06 Feb 2010 14:47:52 +0000

I have written a code to add two numbers in mex. but the code complies successfully but cannot run it can some help me
thanks in regard

#include
#include “mex.h”
#define a_IN prhs[0]
#define b_IN prhs[1]
#define c_OUT plhs[0]
void mexFunction( int nlhs, mxArray *plhs[],
int nrhs, const mxArray*prhs[] )
{
double *a,*b,*c;
a = mxGetPr(a_IN);
b = mxGetPr(b_IN);
c = mxGetPr(c_OUT);
*c = *a + *b;
return;
}

By: terrance

terrance — Mon, 16 Nov 2009 20:00:16 +0000

Hi Shawn, Why if Matlab stores matrices as column major is the ‘linear’ scheme to address specific values of a matrix in row major fashion; e.g. [x][y], you have to use [y+x*dimy], assuming x = Nrows and y = Ncols.

By: Shawn Lankton

Shawn Lankton — Tue, 20 Oct 2009 14:06:21 +0000

@Dongcai su
Great addition.
mxFree is used in conjunction with mxCalloc
mxDestroyArray is used in conjunction with Array objects such as those created by mxCreateDoubleArray.

By: Dongcai su

Dongcai su — Sat, 17 Oct 2009 02:24:30 +0000

Hi lankton:
Your briefly written tutorial is very helpful, but I believe that you had missed something: “Free up the dynamically located memory.” which is:
mxDestroyArray(a_in_m);
mxDestroyArray(b_in_m);

By: Samir Ben Abid

Samir Ben Abid — Thu, 20 Aug 2009 09:47:11 +0000

Thank you for this great tutorial :)

By: Shawn Lankton

Shawn Lankton — Tue, 11 Aug 2009 13:38:16 +0000

Interesting. I’m glad you got it working, though!

By: Anonymous

Anonymous — Tue, 11 Aug 2009 07:54:00 +0000

im using ubuntu 9.04 jaunty. gcc only failed to compile the *.cpp because it needs g++ compiler. so i installed the compiler and it worked well. thx

By: Shawn Lankton

Shawn Lankton — Wed, 29 Apr 2009 13:54:41 +0000

To compile multiple c files use

>>mex file1.c file2.c file3.c

By: Davids

Davids — Wed, 11 Mar 2009 23:15:26 +0000

Thank you for your short MEX tutorial

If I have 10 file.c connect between them, what will be written in the MATLAB command to compile the file that I want to execute.
for example for one file you have written “mex demo.cpp”

Thank you

By: Pejman

Pejman — Thu, 29 Jan 2009 16:58:04 +0000

It was great help, thanks for nice demo.
Could you please inform me on possible mex file references, or a user guide?

Pejman