'Out of memory' mex file

Two issues in the code snippet:

void mexFunction(int nlhs,mxArray *plhs[],int nrhs,const mxArray *prhs[]) {

    const mwSize *dimsG = mxGetDimensions(prhs[1]);
    unsigned int Nstates = dimsG[0];
    unsigned int Nsamples = dimsG[1];
    unsigned int Nmix = dimsG[2];
    unsigned int ObsDim = mxGetM(prhs[0]);

    if(Nmix == 0)Nmix=1;

    const mwSize dims[]={ObsDim,Nmix,Nstates};
    const mwSize dimsgam[]={Nstates,Nmix};

    plhs[0] = mxCreateNumericArray(3,dims,mxDOUBLE_CLASS,mxREAL);
    double* mu = mxGetPr(plhs[0]);
    plhs[1] = mxCreateNumericArray(2,dimsgam,mxDOUBLE_CLASS,mxREAL);
    double* gamsumRet = mxGetPr(plhs[1]);        
    double* X = mxGetPr(prhs[0]);
    double* gamma = mxGetPr(prhs[1]);

    for(unsigned int i=0;i<Nstates;++i)
        for(unsigned int m=0;m<Nmix;++m){
            double* sums= (double*)calloc(ObsDim,sizeof(double));
            if(sums == NULL){
                mexPrintf("\n No Memory Left");
                break;
             }
            double gamsum = 0.0;

            for(unsigned int j=0;j<Nsamples;++j){
                for(unsigned int k=0;k<ObsDim;++k)
                    sums[k] = sums[k]+ X[ObsDim*j+k]*gamma[Nstates*j+Nstates*Nsamples*m+i];
                gamsum = gamsum+gamma[Nstates*Nsamples*m+Nstates*j+i];
            }

                for(unsigned int k=0;k<ObsDim;++k)
                    mu[ObsDim*Nmix*i+ObsDim*m+k] = sums[k];
        gamsumRet[Nstates*m+i]= gamsum;
        free(sums);    
        }   
}

Issue-1 :The code throws 'Out Of Memory' error every few runs. (Not every run). The code that calls it uses quite some memory. I wish to know if there's something I'm missing as far as memory management is concerned in this function.

Issue-2: The result of this code gets returned as a 3-D matrix to which I add another 3-D matrix with exact same dimensions and initialised to zero. i.e,

mma = zeros(ObsDim,Nmix,Nstates);

mma = mma+<value-returned from function>

Sometimes this value is correctly added and quite a few other times the error- 'Array dimensions must match for binary array op.' is returned.

None of these problems occur if I use a matlab script(that does the same job) instead of this mex function

Please Help.

[James Tursa]

Is MATLAB throwing an "Out Of Memory" error, or are you simply getting your "No Memory Left" message printed out?

[Jan]

Do not rely on unsigned int being identical to mwSize.