Initial commit

2020-12-07 19:26:38 +01:00 · 2020-12-07 19:26:38 +01:00 · 87c866eaed
commit 87c866eaed
6 changed files with 607 additions and 0 deletions
--- a/grayscott.dyalog
+++ b/grayscott.dyalog
@ -0,0 +1,23 @@
+ ⎕IO←0
+ ⍝ Discrete Laplacian
+ lapl←(⊃(+/1 ¯1(⌽+⊖)¨⊂)-(⊂4∘×))
+ ⍝ Gray-Scott update
+ diffa←{dt×(da×lapl ⍺)+(-⍺×⍵*2)+f×1-⍺}
+ diffb←{dt×(db×lapl ⍵)+(⍺×⍵*2)-⍵×k+f}
+ update←{⍵+(⊃⍵[0])((⊂diffa),(⊂diffb))⊃⍵[1]}
+ ⍝ Parameters
+ dt da db f k←1.0 0.16 0.08 0.060 0.062
+ ⍝ Initialization
+ N←200
+ A←0.8+0.2×?N N⍴0
+ A[((N÷2)-10)+⍳20;((N÷2)-10)+⍳20]←0.5
+ B←0.2×?N N⍴0
+ B[((N÷2)-10)+⍳20;((N÷2)-10)+⍳20]←0.25
+ ⍝ Run
+ steps←10000
+ Ap Bp←(update⍣steps)A B
+ ⍝ ' ⌺'[Ap>0.5]
+ ⍝ Export to image file
+ mat2pbm←{'P1'(⍕⌽⍴⍵),⍕¨↓⍵>0.5}  ⍝ black and white
+ mat2pgm←{'P2'(⍕⌽⍴⍵),(⊂'255'),⍕¨↓⌊255×⍵}  ⍝ grayscale
+ (⊂mat2pbm Ap)⎕NPUT'img.pnm'1