void inc_array(PyArrayObject *arrayin, double inc){
    double *c;
    int m, n;

    printf("from inc_array\n");
    printf("dimensions: %d, type: %d\n", PyArray_NDIM(arrayin), PyArray_TYPE(arrayin));
    m = PyArray_DIM(arrayin,0);
    n = PyArray_DIM(arrayin,1);

    c = getptr_to_pyarray_double(arrayin);
    for (int i=0; i<m*n; i++)
        c[i] += inc;
}