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37 lines
1.0 KiB
Smalltalk
37 lines
1.0 KiB
Smalltalk
"Mandelbrot — escape-time iteration of z := z² + c starting at z₀ = 0.
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Returns the number of iterations before |z|² exceeds 4, capped at
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maxIter. Classic-corpus program for the Smalltalk-on-SX runtime."
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Object subclass: #Mandelbrot
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instanceVariableNames: ''!
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!Mandelbrot methodsFor: 'iteration'!
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escapeAt: cx and: cy maxIter: maxIter
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| zx zy zx2 zy2 i |
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zx := 0. zy := 0.
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zx2 := 0. zy2 := 0.
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i := 0.
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[(zx2 + zy2 < 4) and: [i < maxIter]] whileTrue: [
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zy := (zx * zy * 2) + cy.
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zx := zx2 - zy2 + cx.
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zx2 := zx * zx.
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zy2 := zy * zy.
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i := i + 1].
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^ i!
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inside: cx and: cy maxIter: maxIter
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^ (self escapeAt: cx and: cy maxIter: maxIter) >= maxIter! !
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!Mandelbrot methodsFor: 'grid'!
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countInsideRangeX: x0 to: x1 stepX: dx rangeY: y0 to: y1 stepY: dy maxIter: maxIter
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| x y count |
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count := 0.
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y := y0.
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[y <= y1] whileTrue: [
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x := x0.
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[x <= x1] whileTrue: [
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(self inside: x and: y maxIter: maxIter) ifTrue: [count := count + 1].
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x := x + dx].
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y := y + dy].
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^ count! !
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