Hi! >>> signal.sepfir2d(resize(arange(400.), (20, 20)), [1], [1]) Ok >>> signal.sepfir2d(arange(400.), [1], [1]) Returns without exception set, still ok. >>> signal.sepfir2d(resize(arange(400.), (20, 20)), [1], []) Segmentation fault End of Python session. bye, Kasper