# Difference between revisions of "Isotropic non-totalistic Life-like cellular automaton"

Apple Bottom (talk | contribs) m (Apple Bottom moved page Non-totalistic Life-like cellular automaton to Isotropic non-totalistic Life-like cellular automaton without leaving a redirect: This is really about the isotropic case.) |
Apple Bottom (talk | contribs) (Avoid confusion about (possibly non-isotropic) non-totalistic vs. isotropic non-totalistic specifically.) |
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− | ''' | + | '''Isotropic non-totalistic Life-like cellular automata''' are a generalization of [[Life-like cellular automata]]. |

− | + | Isotropic non-totalistic rules are described using [[Hensel notation]], an extension of [[rulestring|B/S notation]] developed by [[Alan Hensel]] additionally describing allowed or forbidden configurations. Each digit in the rule's birth and survival conditions is followed by an optional suffix, with each allowed configuration described by a specific letter; a minus sign may be used to forbid configurations rather than allow them. If no configurations are specified, all are considered to be allowed, as in the totalistic case. This notation is not used by [[non-isotropic Life-like cellular automata]]. | |

For instance, B2-a/S12 (the "[[Just Friends]]" rule) indicates that a live cell will survive on 1 or 2 neighbors, or a dead cell get born on 2 neighbors, except when they are adjacent. | For instance, B2-a/S12 (the "[[Just Friends]]" rule) indicates that a live cell will survive on 1 or 2 neighbors, or a dead cell get born on 2 neighbors, except when they are adjacent. | ||

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− | Rules using the [[von Neumann neighbourhood]] can be simulated via non-totalistic rules on the [[Moore neighbourhood]]; for example, B1/SV becomes B1e/S. | + | Rules using the [[von Neumann neighbourhood]] can be simulated via isotropic non-totalistic rules on the [[Moore neighbourhood]]; for example, B1/SV becomes B1e/S. |

==Hexagonal neighbourhood== | ==Hexagonal neighbourhood== | ||

− | It is possible to define non-totalistic Life-like CAs on a hexagonal grid as well. The following table describes all possible neighborhood configurations for the [[hexagonal neighbourhood]], using notation due to [[Paul Callahan]];<ref>{{cite web|url=http://www.radicaleye.com/lifepage/hexrule.txt|title=Experiments with a somewhat "Life-like" hexagonal CA (long)|author=Paul Callahan|date=December 3, 1997|accessdate=September 29, 2017}}</ref><ref>http://www.conwaylife.com/forums/download/file.php?id=261</ref> the names ''ortho'', ''meta'' and ''para'' were chosen in analogy to [https://en.wikipedia.org/wiki/Arene_substitution_pattern arene substitution patterns] in aromatic chemistry: | + | It is possible to define isotropic non-totalistic Life-like CAs on a hexagonal grid as well. The following table describes all possible neighborhood configurations for the [[hexagonal neighbourhood]], using notation due to [[Paul Callahan]];<ref>{{cite web|url=http://www.radicaleye.com/lifepage/hexrule.txt|title=Experiments with a somewhat "Life-like" hexagonal CA (long)|author=Paul Callahan|date=December 3, 1997|accessdate=September 29, 2017}}</ref><ref>http://www.conwaylife.com/forums/download/file.php?id=261</ref> the names ''ortho'', ''meta'' and ''para'' were chosen in analogy to [https://en.wikipedia.org/wiki/Arene_substitution_pattern arene substitution patterns] in aromatic chemistry: |

{| class="wikitable" style="margin-left: auto; margin-right: auto; border: none;" | {| class="wikitable" style="margin-left: auto; margin-right: auto; border: none;" | ||

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− | Golly does not support non-totalistic hexagonal rules using this syntax, so they must instead be simulated using either rule tables or [[Non-isotropic Life-like cellular automaton|MAP]]. | + | Golly does not support isotropic non-totalistic hexagonal rules using this syntax, so they must instead be simulated using either rule tables or [[Non-isotropic Life-like cellular automaton|MAP strings]]. |

==Soup-searching non-totalistic rules== | ==Soup-searching non-totalistic rules== | ||

− | [[Adam P. Goucher]]'s [[apgsearch]] was modified to support non-totalistic rules by [[Aidan F. Pierce]] on December 17, 2015.<ref>{{cite web|url=http://www.conwaylife.com/forums/viewtopic.php?f=9&t=1480&p=25942#p25942|author=Aidan F. Pierce|title=Re: Hacking apgsearch|date=December 17, 2015|accessdate=June 12, 2016|work=ConwayLife.com forums}}</ref> [[Catagolue]] gained the ability to census non-totalistic rules in late January 2016.<ref>{{cite web|url=http://www.conwaylife.com/forums/viewtopic.php?f=7&t=1784&start=225#p26878|author=Adam P. Goucher|title=Re: apgsearch v2.2|date=January 21, 2016|accessdate=June 12, 2016|work=ConwayLife.com forums}}</ref> apgsearch (apgluxe) 4.2, released on September 10, 2017, can search non-totalistic rules without B0. | + | [[Adam P. Goucher]]'s [[apgsearch]] was modified to support isotropic non-totalistic rules by [[Aidan F. Pierce]] on December 17, 2015.<ref>{{cite web|url=http://www.conwaylife.com/forums/viewtopic.php?f=9&t=1480&p=25942#p25942|author=Aidan F. Pierce|title=Re: Hacking apgsearch|date=December 17, 2015|accessdate=June 12, 2016|work=ConwayLife.com forums}}</ref> [[Catagolue]] gained the ability to census isotropic non-totalistic rules in late January 2016.<ref>{{cite web|url=http://www.conwaylife.com/forums/viewtopic.php?f=7&t=1784&start=225#p26878|author=Adam P. Goucher|title=Re: apgsearch v2.2|date=January 21, 2016|accessdate=June 12, 2016|work=ConwayLife.com forums}}</ref> apgsearch (apgluxe) 4.2, released on September 10, 2017, can search isotropic non-totalistic rules without [[B0]]. |

==See also== | ==See also== | ||

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* {{cite web|author=Alan Hensel|url=http://www.ibiblio.org/lifepatterns/neighbors.html|title=Rule notation|accessdate=2016-06-12}} (note that the table on this page describes an earlier version of Hensel notation that has fallen into disuse) | * {{cite web|author=Alan Hensel|url=http://www.ibiblio.org/lifepatterns/neighbors.html|title=Rule notation|accessdate=2016-06-12}} (note that the table on this page describes an earlier version of Hensel notation that has fallen into disuse) | ||

− | [[Category:Cellular automata| | + | [[Category:Cellular automata| Isotropic non-totalistic Life-like cellular automaton]] |

__NOTOC__ | __NOTOC__ |

## Revision as of 08:46, 19 November 2017

**Isotropic non-totalistic Life-like cellular automata** are a generalization of Life-like cellular automata.

Isotropic non-totalistic rules are described using Hensel notation, an extension of B/S notation developed by Alan Hensel additionally describing allowed or forbidden configurations. Each digit in the rule's birth and survival conditions is followed by an optional suffix, with each allowed configuration described by a specific letter; a minus sign may be used to forbid configurations rather than allow them. If no configurations are specified, all are considered to be allowed, as in the totalistic case. This notation is not used by non-isotropic Life-like cellular automata.

For instance, B2-a/S12 (the "Just Friends" rule) indicates that a live cell will survive on 1 or 2 neighbors, or a dead cell get born on 2 neighbors, except when they are adjacent.

This notation has the following symmetry: For any letter *x* and number *n*≠4, *nx* is defined if and only *x*(8-*n*) is defined and moreover *x*(8-*n*) is the complement (change live cells to dead and dead cells to live; ignore the center cell) of *xn*.

The following table describes all possible neighborhood configurations for the Moore neighbourhood; where appropriate, the same configurations apply to the von Neumann neighbourhood:

0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | |
---|---|---|---|---|---|---|---|---|---|

— (no letter) |
|||||||||

c (corner) |
|||||||||

e (edge) |
|||||||||

k (knight) |
|||||||||

a (adjacent) |
|||||||||

i | |||||||||

n | |||||||||

y | |||||||||

q | |||||||||

j | |||||||||

r | |||||||||

t | |||||||||

w | |||||||||

z |

Rules using the von Neumann neighbourhood can be simulated via isotropic non-totalistic rules on the Moore neighbourhood; for example, B1/SV becomes B1e/S.

## Hexagonal neighbourhood

It is possible to define isotropic non-totalistic Life-like CAs on a hexagonal grid as well. The following table describes all possible neighborhood configurations for the hexagonal neighbourhood, using notation due to Paul Callahan;^{[1]}^{[2]} the names *ortho*, *meta* and *para* were chosen in analogy to arene substitution patterns in aromatic chemistry:

0 | 1 | 2 | 3 | 4 | 5 | 6 | |
---|---|---|---|---|---|---|---|

— (no letter) |
|||||||

o (ortho) |
|||||||

m (meta) |
|||||||

p (para) |

Golly does not support isotropic non-totalistic hexagonal rules using this syntax, so they must instead be simulated using either rule tables or MAP strings.

## Soup-searching non-totalistic rules

Adam P. Goucher's apgsearch was modified to support isotropic non-totalistic rules by Aidan F. Pierce on December 17, 2015.^{[3]} Catagolue gained the ability to census isotropic non-totalistic rules in late January 2016.^{[4]} apgsearch (apgluxe) 4.2, released on September 10, 2017, can search isotropic non-totalistic rules without B0.

## See also

- Totalistic Life-like cellular automaton
- Non-isotropic Life-like cellular automaton
- Generations
- Larger than Life

## References

- ↑ Paul Callahan (December 3, 1997). "Experiments with a somewhat "Life-like" hexagonal CA (long)". Retrieved on September 29, 2017.
- ↑ http://www.conwaylife.com/forums/download/file.php?id=261
- ↑ Aidan F. Pierce (December 17, 2015). "Re: Hacking apgsearch".
*ConwayLife.com forums*. Retrieved on June 12, 2016. - ↑ Adam P. Goucher (January 21, 2016). "Re: apgsearch v2.2".
*ConwayLife.com forums*. Retrieved on June 12, 2016.

## External links

- Alan Hensel. "Table of non-totalistic neighborhoods". Retrieved on 2016-06-12.
- Alan Hensel. "Rule notation". Retrieved on 2016-06-12. (note that the table on this page describes an earlier version of Hensel notation that has fallen into disuse)