gridloop2 in C; the return array

Create return array:

  a_dims[0] = nx; a_dims[1] = ny;
  a = (PyArrayObject *) PyArray_FromDims(2, a_dims, 
                                         PyArray_DOUBLE);
  if (a == NULL) { 
    printf("creating a failed, dims=(%d,%d)\n",
           a_dims[0],a_dims[1]);
    return NULL; /* PyArray_FromDims raises an exception */ 
  }

After the loop, return a:

  return PyArray_Return(a);