Hi,
On Tue, Apr 2, 2013 at 7:09 PM,
On Tue, Apr 2, 2013 at 5:52 PM, Nathaniel Smith
wrote: On Tue, Apr 2, 2013 at 10:21 PM, Matthew Brett
wrote: This is like observing that if I say "go North" then it's ambiguous about whether I want you to drive or walk, and concluding that we need new words for the directions depending on what sort of vehicle you use. So "go North" means drive North, "go htuoS" means walk North, etc. Totally silly. Makes much more sense to have one set of words for directions, and then make clear from context what the directions are used for -- "drive North", "walk North". Or "iterate C-wards", "store F-wards".
"C" and "Z" mean exactly the same thing -- they describe a way of unraveling a cube into a straight line. The difference is what we do with the resulting straight line. That's why I'm suggesting that the distinction should be made in the name of the argument.
Could you unpack that for the 'ravel' docstring? Because these options all refer to the way of unraveling and not the memory layout that results.
Z/C/column-major/whatever-you-want-to-call-it is a general strategy for converting between a 1-dim representation and a n-dim representation. In the case of memory storage, the 1-dim representation is the flat space of pointer arithmetic. In the case of ravel, the 1-dim representation is the flat space of a 1-dim indexed array. But the 1-dim-to-n-dim part is the same in both cases.
I think that's why you're seeing people baffled by your proposal -- to them the "C" refers to this general strategy, and what's different is the context where it gets applied. So giving the same strategy two different names is silly; if anything it's the contexts that should have different names.
And once we get into memory optimization (and avoiding copies and preserving contiguity), it is necessary to keep both orders in mind, is memory order in "F" and am I iterating/raveling in "F" order (or slicing columns).
I think having two separate keywords give the impression we can choose two different things at the same time.
I guess it could not make sense to do this: np.ravel(a, index_order='C', memory_order='F') It could make sense to do this: np.reshape(a, (3,4), index_order='F, memory_order='F') but that just points out the inherent confusion between the uses of 'order', and in this case, the fact that you can only do: np.reshape(a, (3, 4), index_order='F') correctly distinguishes between the meanings. Best, Matthew