Asymmetric behavior in dtype conversion

[Stéfan van der Walt]

On Wed, Dec 21, 2011 at 11:16 AM, Tony Yu <tsyu80 at gmail.com> wrote:
> I've definitely been bit by example 1 many times.
>
> I think we should check that float images are between 0 and 1 in
> ``util.dtype._convert`` (and either warn or raise an error), but we
> shouldn't have to worry about it elsewhere. That doesn't really solve the
> issue, so...

This check is cheap enough that we should just add it (it may save
more time than it costs in the end).  The rest of the examples are
fairly unusual, and since there's no way to automatically detect those
situations, we'll just expect the users to correctly scale their data
before using it (I am not opposed to adding utility functions for that
purpose, though).

Stéfan