Hi all!

I am trying to write a Matlab mex-file, and I find the c-coding part a bit challenging. I can get the code below to compile, but it doesn't do what is expected:

The trouble seems to be here: seg_i[ii]=cop[i+ii]; cop[i+ii] seems to be what it should be, but I can't seem to get it's value to seg_i[ii]. Also I'm not sure if it is necessary to use pointers here at all. I know that seg_i and seg_j are either M or M+1 in length and Cim is either N-M or N-M-1 in length.Code:#include <math.h> #include "mex.h" /*Subroutine to calculate the Fuzzy Sample Entropy*/ void FSE(double *cop, int M, double r, double c, mwSize N, double *FuzzSampEnt) { mwIndex m, i, ii, j, jj, k, l; double expo, d, *seg_i, *seg_j, count, sumCim, *Cim, CIM[2]; expo=(log(log(pow(2, c)))/log(r)); for (m=M;m<M+2;m++) { seg_i=mxCalloc(m, sizeof(double)); seg_j=mxCalloc(m, sizeof(double)); Cim=mxCalloc(N-m, sizeof(double)); for (i=0; i<N-m; i++) { count=0; for (ii=0; ii<m; ii++){ seg_i[ii]=cop[i+ii];//TROUBLE } for (j=0; j<N-m; j++) { for (jj=0; jj<m; jj++) { seg_j[jj]=cop[j+jj];//TROUBLE } d=0; /*Finding the maximum absolut value of seg_i-seg_j*/ for (k=0; k<m; k++) { if (d < fabs(seg_i[k]-seg_j[k])) { d=fabs(seg_i[k]-seg_j[k]); } } /*if d=0, self match*/ if (d>0) { count+=exp(-(pow(d, expo/c))); } } Cim[i]=count/(N-m-1); } sumCim=0; for(l=0;l<N-m;l++){ sumCim+=Cim[l]; } if (m==M){ CIM[0]=sumCim/(N-m); } else if (m==M+1){ CIM[1]=sumCim/(N-m); } } *FuzzSampEnt=seg_j[k];//-log(CIM[1]/ CIM[0]); mxFree(seg_i); mxFree(seg_j); mxFree(Cim); } /*the gateway function*/ void mexFunction(int nlhs, mxArray *plhs[ ], int nrhs, const mxArray *prhs[ ]) { int M; double *cop, *FuzzSampEnt; double c, r; mwSize N; if(nrhs!=4) { mexErrMsgTxt("Four inputs required (cop,M,r,c)."); } /*Assign pointers*/ cop=mxGetPr(prhs[0]); N=mxGetM(prhs[0]); M=(int)(mxGetScalar(prhs[1])); r=mxGetScalar(prhs[2]); c=mxGetScalar(prhs[3]); plhs[0] = mxCreateDoubleMatrix(1, 1, mxREAL); FuzzSampEnt = mxGetPr(plhs[0]); /*Call the subroutine */ FSE(cop, M, r, c, N, FuzzSampEnt); return; }

The idea would be to make the code as fast as possible, as fast as possible.. So how would you deal with the seg_i, seg_j and Cim? Can you see what I'm doing wrong in here?

Thank You!

-Aino