The substitution principle is interesting (and, being trained as an
astronomer, not a computer scientist, I had not heard of it before). I
think matrix is indeed obviously wrong here (with indexing being more
annoying, but multiplication being a good example as well).
Perhaps more interesting as a
>
> I don't think so. Dtypes have nothing to do with a whole set of use cases
> that add extra methods or attributes. Random made-up example: user has a
> system with 1000 sensor signals, some of which should be treated with
> robust statistics for . So user writes a
> subclass robust_ndarray, adds
