On Wed, May 23, 2012 at 4:16 PM, Kathleen M Tacina < kathleen.m.tac...@nasa.gov> wrote:
> ** > On Wed, 2012-05-23 at 17:31 -0500, Nathaniel Smith wrote: > > On Wed, May 23, 2012 at 10:53 PM, Travis Oliphant <tra...@continuum.io> > wrote:> To be clear, I'm not opposed to the change, and it looks like we > should go forward.>> In my mind it's not about developers vs. users as > satisfying users is the whole point. The purpose of NumPy is not to make > its developers happy :-). But, users also want there to *be* developers on > NumPy so developer happiness is not irrelevant.>> In this case, though, there > are consequences for users because of the double copy if a user wants to make > their code future proof. We are always trading off predicted > user-experiences. I hope that we all don't have the same perspective on > every issue or more than likely their aren't enough voices being heard from > real users. > I'm not really worried about users who have a problem with thedouble-copy. > It's a totally legitimate concern, but anyone who hasthat concern has already > understood the issues well enough to be ableto take care of themselves, and > decided that it's worth the effort tospecial-case this. They can check > whether the returned array has .baseset to tell whether it's an array or a > view, use a temporary hack tocheck for the secret warning flag in > arr.flags.num, check the numpyversion, all sorts of things to get them > through the one version wherethis matters. The suggestion in the docs to make > a copy is not exactlybinding :-). > -- Nathaniel > > > As a "real user", if I care about whether an array arr2 is a copy or a > view, I usually either check arr2.flags.owndata or append copy() to the > statement that created arr2, e.g., arr2 = arr.diagonal().copy(). > > Numpy rules on views vs. copies sometimes require a bit of thought, and so > I'll frequently just check the flags or make a copy instead of thinking. > (More foolproof :).) > > > It seems that there are a number of ways to check if an array is a view. Do we have a preferred way in the API that is guaranteed to stay available? Or are all of the various methods "here to stay"?
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