Problem with MexFunction and MexGetPr

Good morning,

I can't solve the problem of assignment from incompatible pointer type for the x and y pointer. The error that develops in Matlab, could be caused by the wrong use of the mxGetPr function for the x and y matrix pointers, but I don't know how to proceed.

Someone could give me directions.

thank you.

void mexFunction( int nlhs, mxArray *plhs[],int nrhs, const mxArray*prhs[] )
{
    double **x;
    double *z;
    double *p;
    double **y;

    int i = 2;
    int j = 5;

   plhs[0]= mxCreateDoubleMatrix((mwSize)i, (mwSize)j, mxREAL);

    x = mxGetPr(prhs[0]);
    z = mxGetPr(prhs[1]);
    p =mxGetPr(prhs[2]);
    y = mxGetPr(plhs[0]);

    functionsum(y,x,z,p);
    return;
}

Answer 1

[James Tursa]

Impossible to answer without seeing the code for the functionsum( ) function. Maybe you could post that? Maybe all you need to do is this (but this is just a guess w/o seeing your code):

    double *x;
    double *z;
    double *p;
    double *y;

What version of MATLAB are you using?

Btw, you don't need to explicitly cast the i and j arguments since C has automatic type promotion. This would suffice:

    plhs[0]= mxCreateDoubleMatrix( i, j, mxREAL);