e4f5a0598f
original array strict instead of returning a new strict array. (Finally!) The hard part is keeping the Array type covariant. The solution is to keep the store in the closure of the array's procedure instead of in the Array struct itself.
61 lines
2.3 KiB
Racket
61 lines
2.3 KiB
Racket
#lang typed/racket
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(require typed/racket/base
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math/array
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typed/rackunit)
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(: mandelbrot (Float Integer -> (Array Integer)))
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(define (mandelbrot step max-iters)
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(define x (list->array (sequence->list (in-range -2.0 0.800001 step))))
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(define y (array-slice-ref (list->array (sequence->list (in-range -1.4 1.400001 step)))
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(list ::... (::new 1))))
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(define c (array->fcarray (array-make-rectangular x y)))
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(define-values (z divtime)
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(for/fold: ([z : FCArray c]
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[divtime : (Array Integer) (array max-iters)]
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) ([i (in-range max-iters)])
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(let ([z (fcarray+ (fcarray-sqr z) c)])
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(values z (array-strict (array-if (array-and (array> (fcarray-magnitude z) (array 4.0))
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(array= divtime (array max-iters)))
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(array i)
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divtime))))))
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divtime)
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(check-true
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(equal? (mandelbrot 0.2 20)
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(array #[#[0 1 1 1 1 1 1 1 1 1 1 1 1 1 1]
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#[1 1 1 1 1 1 2 2 2 3 2 2 1 1 1]
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#[1 1 1 1 1 2 2 2 3 6 20 3 2 1 1]
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#[1 1 1 2 2 2 3 4 5 20 17 4 3 2 1]
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#[1 1 2 2 3 3 4 11 20 20 20 10 14 2 2]
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#[1 2 3 4 6 6 6 20 20 20 20 20 9 3 2]
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#[2 3 4 6 18 20 14 20 20 20 20 20 20 3 2]
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#[20 20 20 20 20 20 20 20 20 20 20 20 5 3 2]
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#[2 3 4 6 18 20 14 20 20 20 20 20 20 3 2]
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#[1 2 3 4 6 6 6 20 20 20 20 20 9 3 2]
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#[1 1 2 2 3 3 4 11 20 20 20 10 14 2 2]
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#[1 1 1 2 2 2 3 4 5 20 17 4 3 2 1]
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#[1 1 1 1 1 2 2 2 3 6 20 3 2 1 1]
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#[1 1 1 1 1 1 2 2 2 3 2 2 1 1 1]
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#[0 1 1 1 1 1 1 1 1 1 1 1 1 1 1]])))
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#;
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(begin
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(require images/flomap)
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(: array->flomap ((Array Real) -> flomap))
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(define (array->flomap arr)
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(let ([arr (array->flarray arr)])
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(define ds (array-shape arr))
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(match ds
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[(vector h w) (flomap (flarray-data arr) 1 w h)]
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[(vector h w c) (flomap (flarray-data arr) c w h)]
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[_ (error 'array->flomap "expected array with 2 or 3 dimensions; given shape ~e" ds)])))
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(define fm
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(array->flomap
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(time (mandelbrot 0.007 20))))
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(flomap-size fm)
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(flomap->bitmap (flomap-normalize fm)))
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