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 Iâm curious about the difference of Pharoâs 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?