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 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 > >
