code: def vecs_to_datmesh(x, y):
      
      x, y = meshgrid(x, y)
      out = zeros(x.shape + (2,), dtype=float)
      out[:, :, 0] = x
      out[:, :, 1] = y
      return out
docs: Converts input arguments x and y to a 2d meshgrid,
      suitable for calling Means, Covariances and Realizations.