32 lines
1 KiB
BQN
32 lines
1 KiB
BQN
⟨PBM,PPM⟩←•Import"../bqn-graphics/pnm.bqn"
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⟨Inferno,Magma,Viridis⟩←•Import"../bqn-graphics/colormaps.bqn"
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# Parameters
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dt‿da‿db‿f‿k←⟨1.0,0.16,0.08,0.060,0.062⟩
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n←500 # image size
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m←150 # seed size at the center of the image
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# Discrete Laplacian
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Lapl←(+´∘∾1‿¯1(⌽⋈⌽˘)¨<)-4⊸×
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# Gray-Scott update
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UpdateA←{𝕨+dt×(da×Lapl 𝕨)+(-𝕨×𝕩⋆2)+f×1-𝕨}
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UpdateB←{𝕩+dt×(db×Lapl 𝕩)+(𝕨×𝕩⋆2)-𝕩×k+f}
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Update←(UpdateA⋈UpdateB)´
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# Initialization
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a←n‿n⥊1
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SquareMask←{𝕩‿𝕩↑(-𝕨‿𝕨+𝕩÷2)↑(2×𝕨‿𝕨)⥊1}
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CircleMask←{(𝕨×𝕨)≥(⌽∘⍉∾⍉)(⌽∾⊢)+○(⋆⟜2)⌜˜↕𝕩÷2}
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mask←(n‿n•rand.Range 2)×m CircleMask n
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b←mask⌈0.05×n‿n•rand.Range 0
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# Run
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Step←{stepsize 𝕊 i‿a‿b:
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•Show i×stepsize
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ap‿bp←Update⍟stepsize a‿b
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("out/step"∾(¯5↑∾•Fmt¨5-⊸↑i)∾".pnm")•file.Chars (PPM ⌊255×>Viridis¨1-a)∾@+10
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(i+1)‿ap‿bp
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}
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50 Step•_while_(600⊸>∘⊑⊢) 0‿a‿b
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•Out""
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