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)
> 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?
>
>
