Thanks for sharing, this is indeed something quite subtle.
> On 20 Mar 2020, at 16:19, Tim Mackinnon <tim@testit.works> wrote:
>
> Actually I can answer my own question - its the difference between #sum and
> #sumNumbers (and an easy mistake to make - I almost wish that sum was the
> sumNumbers implementation and there was a sumSample that behaved like now)
There was a *LOT* of debate about that (especially that #() sum isZero).
I also would would prefer #sum to be like you describe.
>> On 20 Mar 2020, at 14:52, Tim Mackinnon <tim@testit.works> wrote:
>>
>> Hi guys - I recall this came up a few months ago, but I’m curious about the
>> difference of Pharo’s use of Float64 vs Python - as I assumed that if
>> languages use the same IEEE spec (or whatever spec it is) that simple stuff
>> would be quite similar.
>>
>> I am curious why in Python adding these numbers:
>>
>> y = 987.9504418944 + 815.2627636718801 + 1099.3898999037601 +
>> 1021.6996069333198 + 1019.8750146478401 + 1084.5603759764 +
>> 1008.2985131833999 + 1194.9564575200002 + 893.9680444336799 +
>> 1032.85460449136 + 905.9324633786798 + 1024.2805590819598 +
>> 784.5488305664002 + 957.3522631840398 + 1001.7526196294
>> print(y)
>> print(y / 15)
>>
>> Gives:
>>
>> 14832.682458496522
>> 988.8454972331015
>>
>> In pharo I have noticed an anomaly which I thought was precision but it may
>> be something odd with iterators.
>>
>> y := 987.9504418944 + 815.2627636718801 + 1099.3898999037601 +
>> 1021.6996069333198 + 1019.8750146478401 + 1084.5603759764 +
>> 1008.2985131833999 + 1194.9564575200002 + 893.9680444336799 +
>> 1032.85460449136 + 905.9324633786798 + 1024.2805590819598 +
>> 784.5488305664002 + 957.3522631840398 + 1001.7526196294.
>> y.
>> y / 15.
>>
>>
>> Gives the same as Python.
>>
>>
>> BUT:
>>
>> z := {987.9504418944 . 815.2627636718801 . 1099.3898999037601 .
>> 1021.6996069333198 . 1019.8750146478401 . 1084.5603759764 .
>> 1008.2985131833999 . 1194.9564575200002 . 893.9680444336799 .
>> 1032.85460449136 . 905.9324633786798 . 1024.2805590819598 .
>> 784.5488305664002 . 957.3522631840398 . 1001.7526196294} sum.
>> z.
>> z / 15.
>>
>>
>> Gives
>> 14832.68245849652
>> 988.8454972331014
>>
>> Is this correct?
>>
>>
>
