One-dimensional cellular automata: Difference between revisions

An alternative approach is to represent the automaton as a string. The following

solution takes advantage of the implicit type coercions between string and numeric

values in Icon and Unicon. It also surrounds the automaton with a border of 'dead'

(always 0) cells to eliminate the need to special case the first and last cells in

the automaton. Although the main procedure displays up to the first 10 generations,

the evolve procedure fails if a new generation is unchanged from the previous, stopping

the generation cycle early.

<lang unicon>procedure main(A)

A := if *A = 0 then ["01110110101010100100"]

CA := show("0"||A[1]||"0") # add always dead border cells

every CA := show(|evolve(CA)\10) # limit to max of 10 generations

end

procedure show(ca)

write(ca[2:-1]) # omit border cells

return ca

end

procedure evolve(CA)

newCA := repl("0",*CA)

every newCA[i := 2 to (*CA-1)] := (CA[i-1]+CA[i]+CA[i+1] = 2, "1")

return CA ~== newCA # fail if no change

end</lang>

A couple of sample runs:

<pre>->odca

01110110101010100100

01011111010101000000

00110001101010000000

00110001110100000000

00110001011000000000

00110000111000000000

00110000101000000000

00110000010000000000

00110000000000000000

->odca 01110110

01110110

01011110

00110010

00110000

-></pre>