I would like to wrap up this discussion.
> On 05 Dec 2015, at 18:14, stepharo <[email protected]> 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
