> On 20 Dec 2015, at 14:57, Tudor Girba <tu...@tudorgirba.com> wrote: > > Hi, > > It’s clear that choices we would make would not be the same :). So, let’s > drop past discussions and stay with the current situation. Do you agree with > the observation that in the proposal of Max #sum and #sum: would not share > the same meaning? If yes, do you agree that it would be misleading from the > outside?
The overal meaning is the same, IMO, summing a number of things (most often numbers) using #+. The processing block just adds functionality. The behaviour in the case of an empty collection is different yes. I want 0, why, because of https://en.wikipedia.org/wiki/Empty_sum This is about optimisation for the common case. VW had no #sum, I think because of all the points raised in this discussion (you can't always expect numbers and it is not clear what to do with empty collections). Check out the senders of #sum and #sum: in a 50 image. > I would be fine with either answer. I would just want to understand. > > Cheers, > Doru > > >> On Dec 20, 2015, at 2:43 PM, Sven Van Caekenberghe <s...@stfx.eu> wrote: >> >> Doru, >> >> For me this whole discussion started because you (the standpoint that you >> take) hijacked the best selector (#sum) for a use case that is much less >> common than adding a collection of numbers which should give 0 when empty >> (you hijack it by not wanting to return 0, which I totally understand, but >> doing so you redefine the meaning/semantics). >> >> Max's point is to make everything more consistent and remove some API. I >> support that too. >> >> Now, I like Max's proposal. >> >> But, you know, my conclusion when the thread ended was that it might be >> better to throw all these selectors away, since #inject:into: covers most >> use cases at least as well and at least as clear. >> >> Sven >> >>> On 20 Dec 2015, at 14:10, Tudor Girba <tu...@tudorgirba.com> wrote: >>> >>> Hi, >>> >>> Could we not have sum, but sumNumbers instead? So, we would end up with: >>> >>> sum:ifEmpty: >>> sum: (with error) >>> sumNumbers (without error) >>> >>> From the outside, #sum: looks like it should parameterize #sum, but the >>> implementation is actually different. So, given that in this implementation >>> #sum is not a special case of #sum: the two should be named differently to >>> reflect that difference. Hence my proposal is to keep #sumNumbers instead >>> of #sum. >>> >>> Cheers, >>> Doru >>> >>> >>>> On Dec 20, 2015, at 1:47 PM, Max Leske <maxle...@gmail.com> wrote: >>>> >>>>> >>>>> On 20 Dec 2015, at 13:43, Gabriel Cotelli <g.cote...@gmail.com> wrote: >>>>> >>>>> Max, >>>>> >>>>> sum: aBlock ifEmpty: emptyBlock needs to obtain the sample evaluating the >>>>> block. >>>>> >>>>> sum: aBlock ifEmpty: emptyBlock >>>>> | sum sample | >>>>> self isEmpty ifTrue: [ ^ emptyBlock value ]. >>>>> sample := aBlock value: self anyOne. >>>>> sum := self >>>>> inject: sample >>>>> into: [ :accum :each | accum + (aBlock value: each) ]. >>>>> ^ sum - sample >>>> >>>> >>>> Thanks! Missed that. >>>> >>>>> >>>>> On Sun, Dec 20, 2015 at 8:59 AM, Max Leske <maxle...@gmail.com> wrote: >>>>> I would like to wrap up this discussion. >>>>> >>>>> >>>>>> On 05 Dec 2015, at 18:14, stepharo <steph...@free.fr> wrote: >>>>>> >>>>>> So what is the conclusion? >>>>>> I like the idea of Esteban M to have iterator because it moves some >>>>>> behavior out of core classes. >>>>>> >>>>>> [[[ >>>>>> >>>>>> aCollection arithmetic sum: [...] or.... aCollection >>>>>> arithmetic avg. >>>>>> >>>>>> ]]] >>>>>> >>>>> >>>>> While I think that iterators are an intriguing idea I also believe that >>>>> they are beyond the scope of this issue. If anybody wants to follow up on >>>>> iterators (or unit types for that matter) please start a new thread / >>>>> issue. >>>>> >>>>> >>>>> I propose to use Sven’s version for #sum:ifEmpty:. The result would be >>>>> these three methods: >>>>> >>>>> sum >>>>> ^ self >>>>> sum: [ :each | each ] >>>>> ifEmpty: [ 0 ] >>>>> >>>>> sum: aBlock >>>>> ^ self >>>>> sum: aBlock >>>>> ifEmpty: [ self errorEmptyCollection ] >>>>> >>>>> sum: aBlock ifEmpty: emptyBlock >>>>> | sum sample | >>>>> self isEmpty ifTrue: [ ^ emptyBlock value ]. >>>>> sample := self anyOne. >>>>> sum := self >>>>> inject: sample >>>>> into: [ :accum :each | accum + (aBlock value: each) ]. >>>>> ^ sum - sample >>>>> >>>>> >>>>> I’ve attached a couple of benchmark results below. To me they show that >>>>> 1. the new implementation is maybe a tiny bit slower but insignificantly >>>>> so (if you’re going for performance you’ll probably write your own >>>>> optimised version anyway) >>>>> 2. there is no need to duplicate the code (like #sum and #sum: currently >>>>> do). It’s perfectly fine to delegate to #sum:ifEmpty: >>>>> >>>>> >>>>> >>>>> In addition to the above changes I would like to remove #detectSum: (-> >>>>> #sum:) and #sumNumbers (-> #sum). >>>>> >>>>> >>>>> Note that once we agree on changing this API, we will need to also change >>>>> #detectMin:, #detectMax:, #min, #max as well as all overrides (e.g. >>>>> RunArray, Interval) of these and of #sum et. al. to stay consistent. The >>>>> changes would of course be in line with this change, such that every >>>>> operation has a unary selector with a sensible default, one that takes a >>>>> block and throws an error for empty collections and a third that takes a >>>>> block for the iteration and one for the empty case. >>>>> >>>>> >>>>> Please cast your vote for these changes: >>>>> >>>>> 1. Do you agree to changing #sum and #sum: in the suggested way? >>>>> >>>>> 2. Do you agree to the removal of #detectSum:? >>>>> >>>>> 3. Do you agree to the removal of #sumNumbers? >>>>> >>>>> 4. Do you agree that the #max and #min selectors also need to be adapted? >>>>> >>>>> >>>>> >>>>> Thanks for you help. >>>>> >>>>> Cheers, >>>>> Max >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> Benchmarks >>>>> ============ >>>>> (Note that these aren’t very good benchmarks. There’s quite some >>>>> variation on each run.) >>>>> >>>>> >>>>> Machine: >>>>> MacBook Pro (15-inch, Early 2011) >>>>> CPU: 2.2 GHz Intel Core i7 >>>>> Memory: 8 GB 1333 MHz DDR3 >>>>> Disk: APPLE SSD TS512C (500 GB) >>>>> >>>>> >>>>> Benchmarks of the current versions: >>>>> >>>>> [ (1 to: 1000000) asArray sum ] benchFor: 10 seconds. >>>>> 75 iterations, 7.470 per second >>>>> >>>>> [ (1 to: 1000000) asArray sum: [ :e | e ] ] benchFor: 10 seconds. >>>>> 72 iterations, 7.128 per second >>>>> >>>>> >>>>> [ (1 to: 100) asArray sum ] benchFor: 10 seconds. >>>>> 1,189,477 iterations, 118,912 per second >>>>> >>>>> >>>>> [ (1 to: 100) asArray sum: [ :e | e ] ] benchFor: 10 seconds. >>>>> 1,171,467 iterations, 117,112 per second >>>>> >>>>> >>>>> >>>>> Benchmarks of the new versions: >>>>> >>>>> [ (1 to: 1000000) asArray sum ] benchFor: 10 seconds. >>>>> 73 iterations, 7.244 per second >>>>> >>>>> [ (1 to: 1000000) asArray sum: [ :e | e ] ] benchFor: 10 seconds. >>>>> 75 iterations, 7.480 per second >>>>> >>>>> [ (1 to: 1000000) asArray sum: [ :e | e ] ifEmpty: [ 0 ] ] benchFor: 10 >>>>> seconds. >>>>> 72 iterations, 7.141 per second >>>>> >>>>> >>>>> [ (1 to: 100) asArray sum ] benchFor: 10 seconds. >>>>> 1,115,827 iterations, 111,560 per second >>>>> >>>>> [ (1 to: 100) asArray sum: [ :e | e ] ] benchFor: 10 seconds. >>>>> 1,154,595 iterations, 115,425 per second >>>>> >>>>> [ (1 to: 100) asArray sum: [ :e | e ] ifEmpty: [ 0 ] ] benchFor: 10 >>>>> seconds. >>>>> 1,102,358 iterations, 110,203 per second >>> >>> -- >>> www.tudorgirba.com >>> www.feenk.com >>> >>> "There are no old things, there are only old ways of looking at them." >>> >>> >>> >>> >>> >> >> > > -- > www.tudorgirba.com > www.feenk.com > > "It's not how it is, it is how we see it." > >
