Re: [Numpy-discussion] Why doesn't array(a, dtype=single, copy=0) downcast a double array.

[Charles R H. <cha...@gm...>]

On 10/16/06, Travis Oliphant <oli...@ie...> wrote:
>
> Charles R Harris wrote:
> > It seems to me that since the behaviour when copy=0 is to make a copy
> > only if necessary, it should find it necessary and make the downcast.
> > After all, array(a, dtype=single, copy=1) does just that without
> > complaint. Some common code in linalg could be replaced if array and
> > asarray would do that operation.
> >
> Well, the fact that it makes the copy without raising an error is
> different behavior from Numeric and should be considered an unintended
> change.
>
> We definitely should make this consistent for copy=0 or copy=1.  The
> only question, is do we raise the error in both cases or allow the
> conversion in both cases.
>
> The long-standing behavior is to raise the error on possible-loss
> conversion and so my opinion is that we should continue with that
> behavior.


Tradition is tradition. My own preference would be to perform the downcast
on the grounds that if I care enough to specify a data type, then that is
what I want. But I'm late to this particular party ;)

Chuck