ConwayLife.com

Posted: **September 6th, 2019, 7:33 pm**

What is the predecessor of a pulsar with the smallest bounding box

Posted: **September 6th, 2019, 7:39 pm**

I'm pretty sure it's this, at only 2x5:

x = 5, y = 2, rule = B3/S23
5o$o3bo!

Anyways, welcome to the forums! For future reference I'd suggest posting basic questions in the thread for basic questions so as to avoid cluttering the General Discussion forum.

Posted: **September 6th, 2019, 8:18 pm**

Ian07 wrote:I'm pretty sure it's this, at only 2x5:
Code: Select all
x = 5, y = 2, rule = B3/S23
5o$o3bo!

Yup, I just ran this

Code: Select all

import golly as g
c=0

while 1:
  c+=1
  g.new(str(c))
  b=1
  ptr = 0
  d=c
  for i in range(16):
    while d!=0:
      if d & b:
        d-=b
        g.setcell(ptr,0,1)
      ptr+=1
      b*=2      
  g.run(4096)
  p1 = int(g.getpop())
  g.run(1)
  p2 = int(g.getpop())
  g.run(1)
  p3 = int(g.getpop())
  
  if p1==48 or p2==48 or p3==48:
     if p1+p2+p3 ==48+56+72:
       g.exit()
  if c%100==0:
    g.fit()
    g.update()

and found that the first one-cell-thick pulsar predecessor is 11 cells wide, so just barely bigger:

Code: Select all

x = 11, y = 1, rule = B3/S23
5ob5o!

A small change to the script (just add if ptr==4: ptr = 0) searches 4-cell-wide patterns instead. The first 4-cell-wide pattern is 3 cells high, so also too big:

Code: Select all

x = 4, y = 3, rule = B3/S23
4o$2b2o$3o!

... and the first 3-cell-wide pattern is 4 cells high (same pattern as above, just rotated). 3x3 was the last hope of beating that 2x5.

Posted: **September 30th, 2019, 11:23 pm**

dvgrn wrote:
Ian07 wrote:I'm pretty sure it's this, at only 2x5:
Code: Select all
x = 5, y = 2, rule = B3/S23
5o$o3bo!

I used to use that predecessor in that Game of Life war game website which has since closed down to amass a large number of pulsars. I think it's the smallest by population as well.

ConwayLife.com

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