[Numpy-discussion] array, asarray as contiguous and friends
tim.hochberg at cox.net
Thu Mar 23 15:07:04 CST 2006
>On 3/23/06, Travis Oliphant <oliphant at ee.byu.edu> wrote:
>>Thus, in my mind, the array call should get another flag keyword that
>>forces a contiguous result.
>Please don't! The fortran flag is bad enough, but has too much history
>behind it. Let's not breed boolean parameters. Sooner or later
>someone will use keword arguments positionally and you will end up
>array([1,2], int8_, 1, 1, 0, 0)
We could always force keyword parameter by using **kwd. That would mess
mess up help() and other introspection tools. Then again, if we want to
discourage overuse of this sort of stuff, perhaps that's not a bad thing ;)
But if we really need access to the C guts of an array, just allow a
dictionary of flags to get plugged in. These would be the same as what
somearray.flags puts out. The new interface for array would be:
Where flags could contain:
CONTIGUOUS : force a copy if object isn't contiguous if
True. [default None]
FORTRAN : force array to be fortran order if True, C order if
False [default None]
OWNDATA : force a copy if
True [default True]
WRITEABLE : Force a copy if object isn't writeable if Tru
ALIGNED : Force a copy if object isn't aligned if True.
UPDATEIFCOPY : Set the UPDATEIFCOPY
flag? [default ???]
With the exception of the FORTRAN, and possibly UPDATEIFCOPY, it would
be an error to set any of these flags to False (Forcing an array to be
discontiguous for instance, makes no sense).
That's a thin interface and it ties together with the flags parameter
nicely. On the downside, it's a little weird, particularly using OWNDATA
for copy, although it is logical once you think about it. It also drops
'minnd' and 'subok'. I wouldn't miss them, but I expect someone would
squawk. You could shoehorn them into flags, but then you lose one of the
chief virtues of this scheme, which is that it makes a strong connection
between the constructor and the flags parameter. 'subok' should be
pretty well taken care of by 'asanyarray' and it would be easy enough to
create an auxilliary function to replicate the 'minnd' functionality.
With this kind of narrow interface, it might make sense to allow the
flags parameter on all of the asX functions. That makes for a nice
uniform, easy to remember, interface. I'm not positive I like this idea
yet, but I thought it was interesting enough to throw into the ring anyway.
Tangentially, I noticed that I can set ALIGNED to False. Isn't that
going to break something somewhere? Should the ALIGNED flag be readonly?
More information about the Numpy-discussion