<div id="__MailbirdStyleContent" style="font-size: 10pt;font-family: Arial;color: #000000;text-align: left" dir="ltr"><div>Hi Levente.</div><div><br></div>
> <span style="font-family: Arial, Helvetica, sans-serif;font-size: 13px">My stance on library methods is that they need to be optimized because you</span><br style="font-family: Arial, Helvetica, sans-serif;font-size: 13px"><span style="font-family: Arial, Helvetica, sans-serif;font-size: 13px">don't know how people will use them. If they are fast, people will be</span><br style="font-family: Arial, Helvetica, sans-serif;font-size: 13px"><span style="font-family: Arial, Helvetica, sans-serif;font-size: 13px">happy. If they are not, you'll leave a bad impression.</span><div class="mb_sig"></div>
<div><span style="font-family: Arial, Helvetica, sans-serif;font-size: 13px"><br></span></div><div><span style="font-family: Arial, Helvetica, sans-serif;font-size: 13px">+1 =)</span></div><div><span style="font-family: Arial, Helvetica, sans-serif;font-size: 13px"><br></span></div><div><span style="font-family: Arial, Helvetica, sans-serif;font-size: 13px">Best,</span></div><div><span style="font-family: Arial, Helvetica, sans-serif;font-size: 13px">Marcel</span></div><blockquote class="history_container" type="cite" style="border-left-style: solid;border-width: 1px;margin-top: 20px;margin-left: 0px;padding-left: 10px;min-width: 500px">
<p style="color: #AAAAAA; margin-top: 10px;">Am 20.02.2021 21:51:24 schrieb Levente Uzonyi <leves@caesar.elte.hu>:</p><div style="font-family:Arial,Helvetica,sans-serif">On Sat, 20 Feb 2021, Tom Beckmann wrote:
<br>
<br>> Hi Levente, hi Nicolas,
<br>>
<br>> To Levente's comment:
<br>> > You left an #asSet send in the above benchmark.
<br>>
<br>> Oups, indeed. But I think the actual measurement was done without the asSet, I just added it later for experimentation. The numbers appear consistent when I rerun the lines without #asSet.
<br>> After sending the mail, I also realized that the setOrigin:corner:/merging4: version is of course not legal, since we mutate the original rectangle that was passed in.
<br>>
<br>> To Nicolas' comment:
<br>> > But that's precisely what we try to avoid here: create lots of
<br>> > intermediate short-lived objects (Rectangle and Point).
<br>> > This is because it may be a performance critical routine.
<br>>
<br>> The most optimized version with the inlined temporaries is a great implementation but looks like quite a beast to me, which in my opinion would be sad for something that appears in our standard library. After looking for
<br>> senders of Rectangle class>>merging: in my trunk image I only saw one critical path in recordInvalidRect:, which appears to on average trigger merging: only once per damaged frame. Is there another use case we know of?
<br>
<br>My stance on library methods is that they need to be optimized because you
<br>don't know how people will use them. If they are fast, people will be
<br>happy. If they are not, you'll leave a bad impression.
<br>
<br>This discussion exists, because Karl changed the method last year and
<br>noticed that the performance got worse[1]. And, while he was convinced
<br>about arguments always being sequenceable, it turned out that they may be
<br>sets as well.
<br>
<br>
<br>Levente
<br>
<br>[1] http://forum.world.st/The-Inbox-Graphics-kfr-434-mcz-tp5119541p5119584.html
<br>
<br>>
<br>> Best regards,
<br>> Tom
<br>>
<br>> On Fri, Feb 19, 2021 at 6:53 PM Levente Uzonyi <leves@caesar.elte.hu> wrote:
<br>> Hi Tom,
<br>>
<br>> On Fri, 19 Feb 2021, Tom Beckmann wrote:
<br>>
<br>> > Hi everyone,
<br>> >
<br>> > just another idea for your consideration:
<br>> >
<br>> > merging3: listOfRects
<br>> > ^ listOfRects reduce: [:a :b |
<br>> > self origin: (a origin min: b origin) corner: (a corner max: b corner)]
<br>> >
<br>> > If you care more about performance than idioms (not even sure if this is legal):
<br>> > merging4: listOfRects
<br>> > ^ listOfRects reduce: [:a :b |
<br>> > a setOrigin: (a origin min: b origin) corner: (a corner max: b corner)]
<br>> >
<br>> > And finally, the, in my opinion, most elegant version. Sadly, it's also the slowest.
<br>> > merging5: listOfRects
<br>> > ^ listOfRects reduce: [:a :b | a quickMerge: b]
<br>> >
<br>> >
<br>> >
<br>> > Some unrepresentative benchmarks:
<br>> >
<br>> > " Levente's version from above with temps "
<br>> > [Rectangle merging2: {0 @ 0 extent: 100 @ 100. -20 @ -20 extent: 80 @ 80. 30 @ 30 extent: 100 @ 100}] bench '3,740,000 per second. 267 nanoseconds per run. 37.46501 % GC time.'
<br>> > " the 'clean' version "
<br>> > [Rectangle merging3: {0 @ 0 extent: 100 @ 100. -20 @ -20 extent: 80 @ 80. 30 @ 30 extent: 100 @ 100}] bench '3,020,000 per second. 331 nanoseconds per run. 40.93181 % GC time.'
<br>> > " the version that mutates rectangles "
<br>> > [Rectangle merging4: {0 @ 0 extent: 100 @ 100. -20 @ -20 extent: 80 @ 80. 30 @ 30 extent: 100 @ 100} asSet] bench '3,330,000 per second. 300 nanoseconds per run. 40.53189 % GC time.'
<br>>
<br>> You left an #asSet send in the above benchmark.
<br>>
<br>>
<br>> Levente
<br>>
<br>> > " using quickMerge "
<br>> > [Rectangle merging5: {0 @ 0 extent: 100 @ 100. -20 @ -20 extent: 80 @ 80. 30 @ 30 extent: 100 @ 100}] bench '2,930,000 per second. 341 nanoseconds per run. 42.32 % GC time.'
<br>> >
<br>> > Best,
<br>> > Tom
<br>> >
<br>> > On Thu, Feb 18, 2021 at 11:17 PM Levente Uzonyi <leves@caesar.elte.hu> wrote:
<br>> > Hi Chris,
<br>> >
<br>> > On Wed, 17 Feb 2021, Chris Muller wrote:
<br>> >
<br>> > > This is what I would do:
<br>> > >
<br>> > > merging: listOfRects
<br>> > > "A number of callers of merge: should use this method."
<br>> > > ^ listOfRects
<br>> > > inject:
<br>> > > (self
<br>> > > origin: Float infinity @ Float infinity
<br>> > > corner: Float infinity negated @ Float infinity negated)
<br>> > > into: [ : rect : each | rect quickMerge: each ]
<br>> > >
<br>> > > With #quickMerge:, you're only creating a new Rectangle when it needed to grow to accomodate the current element, but many of the elements might fit completely, resulting in no additional instantiation.
<br>> Do an
<br>> > analysis of how
<br>> > > many temporary Point objects we create -- hint: it's a ton -- and my own attempts to optimize that in my Kml framework were not fruitful (e.g., ~1%), with a trade-off of duplicating implementation across
<br>> > multiple methods and
<br>> > > making the system's code harder to read and understand and maintain.
<br>> >
<br>> > With my benchmark, your version is slower than the one from 2003,
<br>> > especially when the collection is small. And it doesn't handle the case of
<br>> > empty listOfRects the same way: it silently returns a rectangle instead of
<br>> > raising an error.
<br>> >
<br>> > Here's the version I came up with the other day:
<br>> >
<br>> >
<br>> > merging: listOfRects
<br>> > "A number of callers of merge: should use this method."
<br>> >
<br>> > | minTopLeftX minTopLeftY maxBottomRightX maxBottomRightY |
<br>> > listOfRects do: [ :rectangle |
<br>> > | topLeft bottomRight |
<br>> > topLeft := rectangle topLeft.
<br>> > bottomRight := rectangle bottomRight.
<br>> > minTopLeftX
<br>> > ifNil: [
<br>> > minTopLeftX := topLeft x.
<br>> > minTopLeftY := topLeft y.
<br>> > maxBottomRightX := bottomRight x.
<br>> > maxBottomRightY := bottomRight y ]
<br>> > ifNotNil: [
<br>> > topLeft x < minTopLeftX ifTrue: [ minTopLeftX := topLeft x ].
<br>> > topLeft y < minTopLeftY ifTrue: [ minTopLeftY := topLeft y ].
<br>> > bottomRight x > maxBottomRightX ifTrue: [ maxBottomRightX := bottomRight x ].
<br>> > bottomRight y > maxBottomRightY ifTrue: [ maxBottomRightY := bottomRight y ] ] ].
<br>> > ^self origin: minTopLeftX @ minTopLeftY corner: maxBottomRightX @ maxBottomRightY
<br>> >
<br>> >
<br>> > Levente
<br>> >
<br>> > >
<br>> > > - Chris
<br>> > >
<br>> > >
<br>> > > On Wed, Feb 17, 2021 at 11:27 AM Levente Uzonyi <leves@caesar.elte.hu> wrote:
<br>> > > On Wed, 17 Feb 2021, Marcel Taeumel wrote:
<br>> > >
<br>> > > > Hmm... looking at performance ... why not just add #asSequenceableCollection, which would only impact Set arguments?
<br>> > >
<br>> > > I don't think we have such method. Adding one would raise the usual
<br>> > > question: should it create a new collection or return self if self
<br>> > > already to the requested collection kind?
<br>> > > IIRC currently the only outlier is #asOrderedCollection which always
<br>> > > creates a copy when the receiver is an OrderedCollection, and that
<br>> > > property is being relied on, so it can't be changed...
<br>> > >
<br>> > > > As a programmer, I do not want to choose between #merge: and #quickMerge:. Or similar. :-)
<br>> > >
<br>> > > IMO, we simply need one quick solution. If you have a Set, you may need
<br>> > > that help from the library even more.
<br>> > > #quickMerge: is only good for merging two rectangles. It does not solve
<br>> > > the GC issue #merge: has.
<br>> > >
<br>> > >
<br>> > > Levente
<br>> > >
<br>> > > >
<br>> > > > Best,
<br>> > > > Marcel
<br>> > > >
<br>> > > > Am 13.02.2021 17:05:07 schrieb commits@source.squeak.org <commits@source.squeak.org>:
<br>> > > >
<br>> > > > Nicolas Cellier uploaded a new version of Graphics to project The Inbox:
<br>> > > > http://source.squeak.org/inbox/Graphics-nice.446.mcz
<br>> > > >
<br>> > > > ==================== Summary ====================
<br>> > > >
<br>> > > > Name: Graphics-nice.446
<br>> > > > Author: nice
<br>> > > > Time: 13 February 2021, 5:04:52.453325 pm
<br>> > > > UUID: d13c1db2-370f-4fa6-b7ae-e6766bf0c8fb
<br>> > > > Ancestors: Graphics-dtl.445
<br>> > > >
<br>> > > > Let Rectangle merging:/encompassing: an unordered collection.
<br>> > > >
<br>> > > > =============== Diff against Graphics-dtl.445 ===============
<br>> > > >
<br>> > > > Item was changed:
<br>> > > > ----- Method: Rectangle class>>encompassing: (in category 'instance creation') -----
<br>> > > > encompassing: listOfPoints
<br>> > > > "A number of callers of encompass: should use this method."
<br>> > > > | topLeft bottomRight |
<br>> > > > + topLeft := bottomRight := listOfPoints anyOne.
<br>> > > > + listOfPoints do:
<br>> > > > - topLeft := bottomRight := listOfPoints first.
<br>> > > > - listOfPoints allButFirstDo:
<br>> > > > [:p |topLeft := topLeft min: p.
<br>> > > > + bottomRight := bottomRight max: p].
<br>> > > > - bottomRight := bottomRight max: p].
<br>> > > > ^self origin: topLeft corner: bottomRight
<br>> > > > !
<br>> > > >
<br>> > > > Item was changed:
<br>> > > > ----- Method: Rectangle class>>merging: (in category 'instance creation') -----
<br>> > > > merging: listOfRects
<br>> > > > "A number of callers of merge: should use this method."
<br>> > > > + | aRectangle bottomRight topLeft |
<br>> > > > + aRectangle := listOfRects anyOne.
<br>> > > > + topLeft := aRectangle topLeft.
<br>> > > > + bottomRight := aRectangle bottomRight.
<br>> > > > - | bottomRight topLeft |
<br>> > > > - topLeft := listOfRects first topLeft.
<br>> > > > - bottomRight := listOfRects first bottomRight.
<br>> > > > listOfRects
<br>> > > > + do: [:r | topLeft := topLeft min: r topLeft.
<br>> > > > - allButFirstDo: [:r | topLeft := topLeft min: r topLeft.
<br>> > > > bottomRight := bottomRight max: r bottomRight].
<br>> > > > ^self origin: topLeft corner: bottomRight.
<br>> > > > !
<br>> > > >
<br>> > > >
<br>> > > >
<br>> > > >
<br>> > >
<br>> > >
<br>> > >
<br>> >
<br>> >
<br>> >
<br>>
<br>>
<br>><br></commits@source.squeak.org></leves@caesar.elte.hu></leves@caesar.elte.hu></leves@caesar.elte.hu></div></blockquote></div>