Steven D'Aprano writes: > On Tuesday 15 March 2016 16:26, Jussi Piitulainen wrote: > >> Steven D'Aprano writes: >> >>> Unfortunate or not, it seems to be quite common that "zip" >>> (convolution) discards items when sequences are of different lengths. >> >> Citation needed. Where is zip called convolution? > > Wikipedia :-) > > Unfortunately "convolution" is one of those technical terms with many > related but slightly different meanings. It's used in calculus, signal > processing, geology, biology, probability theory, formal languages, > and more. I don't have a citation for it being used in functional > programming, but is it so hard to believe? A "convolution" is usually > described as something being folded over another thing, which sounds > rather like zip, doesn't it?
I'm asking precisely because the term "convolution" already has more interesting uses that I find somewhat non-trivial, and I don't see zip being one of those. > Take two pieces of paper, say one white and one black, one on top of the > other, and fold them in half, then in half again, then again: > > zero folds = W B > > one fold = W B B W > > two folds = W B B W W B B W > > > which is not that far from what zip would give you: > > W B W B W B W B ... Seems different to me. > I don't know enough about the lambda calculus and other theoretical computer > science topics to give a definitive citation for "zip" being a convolution, > but I do know enough to accept it as plausible. Perhaps someone else can provide citations. At the moment, I think the idea is both new and bad. >> Why should zip be called convolution? > > Why should anything be called anything? > > Don't worry, I'm not suggesting that the zip function be renamed. I'm not worried about "zip". I'm worried about "convolution". It's confusing to adopt an existing term for a different purpose. >>> See https://en.wikipedia.org/wiki/Convolution_%28computer_science%29 >> >> "This article possibly contains original research. Please improve it by >> verifying the claims made and adding inline citations." > > Meh, there are Wikipedia editors that seem to flag just about every article > with that. You could write "water is wet" and technically that's "original > research" that needs a citation. It is so over-used that it is practically > meaningless. In this case, it seems accurate to me. The article makes a factual claim that the term is actually used this way in computer science, with no evidence to back it up. I doubt it. I failed to find evidence myself. Anyone? -- https://mail.python.org/mailman/listinfo/python-list
