> On 01 Dec 2015, at 10:18, Ben Coman <btc@openinworld.com> wrote:
>
> On Tue, Dec 1, 2015 at 4:45 PM, Sven Van Caekenberghe <sven@stfx.eu> wrote:
>> I am all for a cleanup, the current situation is confusing.
>> The basic #sum should be fast AND work for empty collections with 0 as starting element.
>
>> I know why the #anyOne is used, and that use case should be preserved, but it is less common IMHO.
>
> I'm curious to be learn why?

How many times have you summed a collection of things, where (1) you could not start from the number 0 and (2) the operation was #+ ? Me, never, and if I would need that, I would do an #inject:into: myself. Any counter examples that occur a lot ?

> cheers -ben
>
>>
>>> On 01 Dec 2015, at 09:38, Thierry Goubier <thierry.goubier@gmail.com> wrote:
>>>
>>> Hi Max,
>>>
>>> Interesting results...
>>>
>>> replacing the #yourself in newSum: cuts the runtime by a factor of two.
>>> using an [:x | x ] block cost 10% compared to a direct version of sum.
>>>
>>> So the fastest sum is:
>>>
>>> sum
>>>�� �� �� ^ self
>>>�� �� �� �� �� �� �� inject:
>>>�� �� �� �� �� �� �� �� �� �� �� (self ifEmpty: [ ^ 0 ] ifNotEmpty: [ self anyOne ])
>>>�� �� �� �� �� �� �� into: [ :sum :each | sum + each ]
>>>
>>> And
>>>
>>> sum
>>>�� �� ^ self sum: [:x | x ]
>>>
>>> is 10% slower.
>>>
>>> And
>>>
>>> sum
>>>�� �� ^ self sum: #yourself
>>>
>>> is 100% slower (i.e. x2)
>>>
>>> It may be wise to avoid using #yourself for a block.
>>>
>>> Thierry
>>>
>>>
>>> 2015-12-01 9:17 GMT+01:00 Max Leske <maxleske@gmail.com>:
>>> Hi guys,
>>>
>>> Collection defines #sum:, #detectSum: and #sumNumbers:, all of which accomplish the same (in principal) but with subtle differences:
>>>
>>> #sum:
>>> - uses #inject:into: with #anyOne as the injected element and will thus fail for empty collections
>>>
>>> #detectSum:
>>> - uses ���nextValue + sum��� instead of ���sum + nextValue��� which makes it a lot slower when dealing with large numbers (primitive fails and number conversion is necessary)
>>>
>>> #sumNumbers:
>>> - same as #sum but doesn���t fail for empty collections. Only good for numbers though.
>>>
>>>
>>> Benchmarks:
>>>
>>> [ 100 timesRepeat: [ (1 to: 1000000) sum: #yourself ] ] timeToRun 18062
>>> [ 100 timesRepeat: [ (1 to: 1000000) detectSum: #yourself ] ] timeToRun 42391
>>> [ 100 timesRepeat: [ (1 to: 1000000) sumNumbers: #yourself ] ] timeToRun 18096
>>>
>>>
>>>
>>> Can we settle for a single implementation? Such as (modified from #sumNumbers:):
>>>
>>> newSum: aBlock
>>>�� �� �� �� ^ self
>>>�� �� �� �� �� �� �� �� inject: (self
>>>�� �� �� �� �� �� �� �� �� �� �� �� ifEmpty: [ 0 ]
>>>�� �� �� �� �� �� �� �� �� �� �� �� ifNotEmpty: [ self anyOne ])
>>>�� �� �� �� �� �� �� �� into: [ :sum :each |�� sum + (aBlock value: each) ]
>>>
>>> This implementation combines the best of the three implementations I think. Benchmark:
>>>
>>> [ 100 timesRepeat: [ (1 to: 1000000) newSum: #yourself ] ] timeToRun 17955
>>>
>>>
>>> BTW, there is also the message #sum, which suffers from the same problem as #sum: (the implementation is basically a copy). #sum could be implemented as
>>>
>>> sum
>>>�� �� �� �� ^ self sum: [ :x | x ]
>>>
>>>
>>> As for the name for the new method, I suggest #sum:.
>>>
>>> Cheers,
>>> Max
>>>
>>
>>
>