On Fr, 2015-01-30 at 19:52 -0800, Jaime Fernández del Río wrote: > On Thu, Jan 29, 2015 at 8:57 AM, Nathaniel Smith <n...@pobox.com> > wrote: > On Thu, Jan 29, 2015 at 12:56 AM, Jaime Fernández del Río > <jaime.f...@gmail.com> wrote: > [...]
<snip> > > Could we make it more like: check to see if the last dimension > works. > If not, raise an error (and let the user transpose some other > dimension there if that's what they wanted)? Or require the > user to > specify which dimension will absorb the shape change? (If we > were > doing this from scratch, then it would be tempting to just say > that we > always add a new dimension at the end with newtype.itemsize / > oldtype.itemsize entries, or absorb such a dimension if > shrinking. As > a bonus, this would always work, regardless of contiguity! > Except that > when shrinking the last dimension would have to be contiguous, > of > course.) > > > When we roll @ in and people start working with stacks of matrices, we > will probably find ourselves having to create an alias, similar to .T, > for .swapaxes(-1, -2). Searching for the smallest stride allows to > take views of such arrays, which does not work right now because the > array is no longer contiguous globally. > That is true, but I agree with Nathaniel at least as far as that I would prefer a user to be able to safely use `view` even he has not even an inkling about what his memory layout is. One option would be an `axis=-1` default (maybe FutureWarn this from `axis=None` which would look at order, see below -- or maybe have axis='A', 'C' and 'F' and default to 'A' for starters). This even now could start creating bugs when enabling relaxed strides :(, because your good old fortran order complex array being viewed as a float one could expand along the wrong axis, and even without such arrays swap order pretty fast when operating on them, which can create impossibly to find bugs, because even a poweruser is likely to forget about such things. Of course you could argue that view is a poweruser feature and a user using it should keep these things in mind.... Though if you argue that, you can almost just use `np.ndarray` directly ;) -- ok, not really considering how cumbersome it is, but still. - Sebastian > > I guess the main consideration for this is that we may be > stuck with > stuff b/c of backwards compatibility. Can you maybe say a > little bit > about what is allowed now, and what constraints that puts on > things? > E.g. are we already grovelling around in strides and picking > random > dimensions in some cases? > > > Just to restate it: right now we only allow new views if the array is > globally contiguous, so either along the first or last dimension. > > > Jaime > > > -n > > -- > Nathaniel J. Smith > Postdoctoral researcher - Informatics - University of > Edinburgh > http://vorpus.org > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@scipy.org > http://mail.scipy.org/mailman/listinfo/numpy-discussion > > > > > > -- > (\__/) > ( O.o) > ( > <) Este es Conejo. Copia a Conejo en tu firma y ayúdale en sus > planes de dominación mundial. > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@scipy.org > http://mail.scipy.org/mailman/listinfo/numpy-discussion
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