Hmm.  Looking at the results in a relatively up to date Squeak 4.5:

[ 10000 timesRepeat: [ | c | c  := OrderedCollection new: 100000.
 1 to: 10000 do: [ :i | c add: i ] ] ] timeToRun   3624

[ 10000 timesRepeat: [ | c | c  := OrderedCollection new: 10000.
 1 to: 10000 do: [ :i | c add: i ] ] ] timeToRun   2540

[ 10000 timesRepeat: [ | c | c  := OrderedCollection new: 0.
 1 to: 10000 do: [ :i | c add: i ] ] ] timeToRun   2879

[ 10000 timesRepeat: [ | c | c  := OrderedCollection new: 1000.
 1 to: 10000 do: [ :i | c add: i ] ] ] timeToRun   2784

Apparently Squeak takes more time to allocate the large array than Pharo?
That would explain why the first run is so much slower than the other 3 -
the exact opposite of Max's results (for Pharo 1.3 - but inline with Pharo4
- although not as extreme as Pharo4).

Then, what about an array that only adds at the beginning (instead of
end)?  I would expect worse performance - especially if I removed the space
at the beginning.  WIthout any of those changes, though:


[ 10000 timesRepeat: [ | c | c  := OrderedCollection new: 100000.
 1 to: 10000 do: [ :i | c addFirst: i ] ] ] timeToRun    2782

[ 10000 timesRepeat: [ | c | c  := OrderedCollection new: 10000.
 1 to: 10000 do: [ :i | c addFirst: i ] ] ] timeToRun    1845

[ 10000 timesRepeat: [ | c | c  := OrderedCollection new: 0.
 1 to: 10000 do: [ :i | c addFirst: i ] ] ] timeToRun    2052

[ 10000 timesRepeat: [ | c | c  := OrderedCollection new: 1000.
 1 to: 10000 do: [ :i | c addFirst: i ] ] ] timeToRun   1962

Weird that it turned out faster.  Maybe it has to do with the first time it
runs out of room, it move data (and doesn't allocate a new array?).

Stephan's code (in the same image):

[ 10000 timesRepeat: [ | c | c  := OrderedCollection new: 100000.
c add: 1.
2 to: 10000 do: [ :i |  c add: i beforeIndex: (i atRandom) ] ] ] timeToRun
200434

This last is much slower - every time it adds an value, it forces a copy of
the data.  It will not be as fast as the others.

-cbc


On Wed, Jan 14, 2015 at 6:05 AM, Stephan Eggermont <stephan at stack.nl> wrote:

> I'm more worried about this part.
>
> [ 10000 timesRepeat: [ | c |
>                 c  := OrderedCollection new.
>                 c add: 1.
>                  2 to: 10000 do: [ :i |
>                         c add: i beforeIndex: (c atRandom) ] ] ] timeToRun
> "5 min. 30 s."
>
> Stephan
>
>
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