Rule 30 cellular automaton

[tsh73]

as per
en.wikipedia.org/wiki/Rule_30

Also rule 90 (Sierpinsky triangle) and some others.

Variables to be changed:
rule (0..255, but 0 is total empty and 255 is total fill. Anything else will do something)
factor - actually point size. From 1 up.
start - initial condition (upper line). Different density random fills work differently for Rule 184

Have fun

'cellular automata
'rule30 at al
'tsh73 Nov 2019
'v1. Make it work, work right
'v2 work fast
'v3 try to change to 01 and use val - measured seperately, no better
'v4 turn to array instead of string
'out: remove commented code

rule=30    '//chaos
'rule = 110     '//chaos
'rule = 90      '//sierpinsky triangle
'rule = 184      '//majority

factor=3

start=0    'single center 1 (default)
'start=1    '1/3 0, 1/3 1, 1/3 0
'start=2    'random 25% 1
'start=3    'random 50% 1
'start=4    'random 75% 1

nomainwin
global maxX, curr, factor

open "Cellular automata" for graphics_nsb_fs as #gr
#gr "trapclose [quit]"
#gr "down"
#gr "home; posxy cx cy"


#gr "size ";factor

maxX=cx*2
maxY=2*cy
if  cx < maxY then maxY=cx

maxX=int(maxX/factor)
maxY=int(maxY/factor)

dim aLine(maxX, 1)    'maxX, 0..1

curr=0

redim aLine(maxX, 1)    'fill with 0 (if you want call several times)
select case start
case 0
   'initial center point
   aLine(maxX/2, curr)=1
case 1
   '1/3 0, 1/3 1, 1/3 0
   for i = maxX/3 to 2*maxX/3
       aLine(i, curr)=1
   next
case 2
   'random 25% 1
   for i = 1 to maxX
       if rnd(0)<0.25 then aLine(i, curr)=1
   next
case 3
   'random 50% 1
   for i = 1 to maxX
       if rnd(0)<0.5 then aLine(i, curr)=1
   next
case 4
   'random 75% 1
   for i = 1 to maxX
       if rnd(0)<0.75 then aLine(i, curr)=1
   next
case else
   'initial center point
   aLine(maxX/2, curr)=1
end select

#gr "cls"
t0=time$("ms")
y=0
call drawLine y
for y = 1 to maxY
   'make curLine$ out of prevLine$
   prev=curr
   curr=1-curr    '1->0->1
   aLine(1, curr)=0
   for i=2 to maxX-1
       SCAN    'possible break point
       ind=aLine(i-1, prev)*4+_
           aLine(i, prev)*2+_
           aLine(i+1, prev)
       if rule and (2^ind) then c=1 else c=0
       aLine(i, curr)=c
   next
   aLine(maxX, curr)=0
   call drawLine y
   #gr "discard"
next
#gr "flush"

t1=time$("ms")
'notice "Time taken ";t1-t0

'91 sec, 94, 93
'discard - 81
's$->ind binary instead of array search: 61
'skip empty " ": 58,5
'ind as instr/4: slower (64 )
'no draw: 36,6
'alas array(val(s$)) is slower then (s$->ind binary), bia mid and '='
'number array instead of string: 55

wait

[quit]
   timer 0
   close #gr
end

'-------------------------
sub drawLine y
   for i = 1 to maxX
       if aLine(i, curr) then
           #gr "set ";(i-1)*factor;" "; y*factor
           'print i-1, y
       end if
   next
end sub


[B+]

I remember exploring this in early 90's, classic!