Hello. I am trying to write a mex file through MATLAB. This is my first time to deal with C code in general although I have a coding experience in Java. After some research and the test code that I wrote in MATLAB, I successfully implemented mex file and ran fine. After that I tried to add some more code in existing code, MATLAB crashes up every time I ran it. I know that there is not many problems, but I quite don't know how to fix this error.
Here is a code that I wrote. I know that this code is very clumsy and it's because it's my first time to code c. The issue that I have with is almost the last line of the code; for loop.
#include "mex.h"
#include "matrix.h"
void mexFunction( int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[]) {
double *temp, *proj, *proj_spt, *feature, *stim, *spt;
int i, ii, Nstim, Mstim, Nfeat, Mfeat, Mspt, Nspt;
Mstim = mxGetM(prhs[0]); /* Get a dimension of stim */
Nstim = mxGetN(prhs[0]);
Mspt = mxGetM(prhs[2]); /* Get a dimension of spt */
Nspt = mxGetN(prhs[2]);
Mfeat = mxGetM(prhs[1]);
Nfeat = mxGetN(prhs[1]);
plhs[0] = mxCreateDoubleMatrix(Mstim, Nstim, mxREAL);
proj = mxGetPr(plhs[0]);
plhs[1] = mxCreateDoubleMatrix(Mstim, Nstim, mxREAL);
proj_spt = mxGetPr(plhs[1]);
feature = mxGetPr(prhs[1]);
stim = mxGetPr(prhs[0]);
spt = mxGetPr(prhs[2]);
for (i=0;i<(Nstim-Nfeat+1);i++){
temp[i] = 0;
for (ii = 0; ii < Nfeat; ii++){
temp[i] = temp[i] + (feature[ii]*stim[i+ii]);
}
}
for (i=(Nstim-Nfeat+1);i<Nstim;i++){
temp[i] = 0;
for (ii = 0; ii < (Nstim-i); ii++){
temp[i] = temp[i] + (feature[ii]*stim[i+ii]);
}
}
for (i=0;i<Nstim;i++){
proj[i] = temp[i];
}
// This part has an error.
for (i=0;i<Nspt;i++){
ii = spt[i];
mexPrintf("%d is spike time. \n",ii);
}
As you can see, I have tried somethings and really don't want to try more because every time I run this, MATLAB crashes, which is very annoying. The fact that I don't know how to debug the mex file also is being a reason for me not to try.
Could anyone help me out to get through this error? Also I notice that it is not possible for the one to use Mstim (in this case) as an index of the vector or array..Why is it not possible?
For example, I noticed that I get an error if I do this.
for (i = Nfeat ; i < Nstim , i++){
proj[i] = temp[i-Nfeat];
}
Why does this cast an error? FYI, Nstim = 15 and Nfeat = 4 , which is supposed to be length(stim) = 15 and length(feat) = 4 in MATLAB.
