[squeak-dev] The Inbox: Graphics-nice.446.mczLevente Uzonyi leves at caesar.elte.huFri Feb 19 18:53:37 UTC 2021
Hi Tom,
On Fri, 19 Feb 2021, Tom Beckmann wrote:
> Hi everyone,
>
> just another idea for your consideration:
>
> merging3: listOfRects
> ^ listOfRects reduce: [:a :b |
> self origin: (a origin min: b origin) corner: (a corner max: b corner)]
>
> If you care more about performance than idioms (not even sure if this is legal):
> merging4: listOfRects
> ^ listOfRects reduce: [:a :b |
> a setOrigin: (a origin min: b origin) corner: (a corner max: b corner)]
>
> And finally, the, in my opinion, most elegant version. Sadly, it's also the slowest.
> merging5: listOfRects
> ^ listOfRects reduce: [:a :b | a quickMerge: b]
>
>
>
> Some unrepresentative benchmarks:
>
> " Levente's version from above with temps "
> [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.'
> " the 'clean' version "
> [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.'
> " the version that mutates rectangles "
> [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.'
You left an #asSet send in the above benchmark.
Levente
> " using quickMerge "
> [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.'
>
> Best,
> Tom
>
> On Thu, Feb 18, 2021 at 11:17 PM Levente Uzonyi <leves at caesar.elte.hu> wrote:
> Hi Chris,
>
> On Wed, 17 Feb 2021, Chris Muller wrote:
>
> > This is what I would do:
> >
> > merging: listOfRects
> > "A number of callers of merge: should use this method."
> > ^ listOfRects
> > inject:
> > (self
> > origin: Float infinity @ Float infinity
> > corner: Float infinity negated @ Float infinity negated)
> > into: [ : rect : each | rect quickMerge: each ]
> >
> > 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. Do an
> analysis of how
> > 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
> multiple methods and
> > making the system's code harder to read and understand and maintain.
>
> With my benchmark, your version is slower than the one from 2003,
> especially when the collection is small. And it doesn't handle the case of
> empty listOfRects the same way: it silently returns a rectangle instead of
> raising an error.
>
> Here's the version I came up with the other day:
>
>
> merging: listOfRects
> "A number of callers of merge: should use this method."
>
> | minTopLeftX minTopLeftY maxBottomRightX maxBottomRightY |
> listOfRects do: [ :rectangle |
> | topLeft bottomRight |
> topLeft := rectangle topLeft.
> bottomRight := rectangle bottomRight.
> minTopLeftX
> ifNil: [
> minTopLeftX := topLeft x.
> minTopLeftY := topLeft y.
> maxBottomRightX := bottomRight x.
> maxBottomRightY := bottomRight y ]
> ifNotNil: [
> topLeft x < minTopLeftX ifTrue: [ minTopLeftX := topLeft x ].
> topLeft y < minTopLeftY ifTrue: [ minTopLeftY := topLeft y ].
> bottomRight x > maxBottomRightX ifTrue: [ maxBottomRightX := bottomRight x ].
> bottomRight y > maxBottomRightY ifTrue: [ maxBottomRightY := bottomRight y ] ] ].
> ^self origin: minTopLeftX @ minTopLeftY corner: maxBottomRightX @ maxBottomRightY
>
>
> Levente
>
> >
> > - Chris
> >
> >
> > On Wed, Feb 17, 2021 at 11:27 AM Levente Uzonyi <leves at caesar.elte.hu> wrote:
> > On Wed, 17 Feb 2021, Marcel Taeumel wrote:
> >
> > > Hmm... looking at performance ... why not just add #asSequenceableCollection, which would only impact Set arguments?
> >
> > I don't think we have such method. Adding one would raise the usual
> > question: should it create a new collection or return self if self
> > already to the requested collection kind?
> > IIRC currently the only outlier is #asOrderedCollection which always
> > creates a copy when the receiver is an OrderedCollection, and that
> > property is being relied on, so it can't be changed...
> >
> > > As a programmer, I do not want to choose between #merge: and #quickMerge:. Or similar. :-)
> >
> > IMO, we simply need one quick solution. If you have a Set, you may need
> > that help from the library even more.
> > #quickMerge: is only good for merging two rectangles. It does not solve
> > the GC issue #merge: has.
> >
> >
> > Levente
> >
> > >
> > > Best,
> > > Marcel
> > >
> > > Am 13.02.2021 17:05:07 schrieb commits at source.squeak.org <commits at source.squeak.org>:
> > >
> > > Nicolas Cellier uploaded a new version of Graphics to project The Inbox:
> > > http://source.squeak.org/inbox/Graphics-nice.446.mcz
> > >
> > > ==================== Summary ====================
> > >
> > > Name: Graphics-nice.446
> > > Author: nice
> > > Time: 13 February 2021, 5:04:52.453325 pm
> > > UUID: d13c1db2-370f-4fa6-b7ae-e6766bf0c8fb
> > > Ancestors: Graphics-dtl.445
> > >
> > > Let Rectangle merging:/encompassing: an unordered collection.
> > >
> > > =============== Diff against Graphics-dtl.445 ===============
> > >
> > > Item was changed:
> > > ----- Method: Rectangle class>>encompassing: (in category 'instance creation') -----
> > > encompassing: listOfPoints
> > > "A number of callers of encompass: should use this method."
> > > | topLeft bottomRight |
> > > + topLeft := bottomRight := listOfPoints anyOne.
> > > + listOfPoints do:
> > > - topLeft := bottomRight := listOfPoints first.
> > > - listOfPoints allButFirstDo:
> > > [:p |topLeft := topLeft min: p.
> > > + bottomRight := bottomRight max: p].
> > > - bottomRight := bottomRight max: p].
> > > ^self origin: topLeft corner: bottomRight
> > > !
> > >
> > > Item was changed:
> > > ----- Method: Rectangle class>>merging: (in category 'instance creation') -----
> > > merging: listOfRects
> > > "A number of callers of merge: should use this method."
> > > + | aRectangle bottomRight topLeft |
> > > + aRectangle := listOfRects anyOne.
> > > + topLeft := aRectangle topLeft.
> > > + bottomRight := aRectangle bottomRight.
> > > - | bottomRight topLeft |
> > > - topLeft := listOfRects first topLeft.
> > > - bottomRight := listOfRects first bottomRight.
> > > listOfRects
> > > + do: [:r | topLeft := topLeft min: r topLeft.
> > > - allButFirstDo: [:r | topLeft := topLeft min: r topLeft.
> > > bottomRight := bottomRight max: r bottomRight].
> > > ^self origin: topLeft corner: bottomRight.
> > > !
> > >
> > >
> > >
> > >
> >
> >
> >
>
>
>
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