Search found 571 matches

by pcallahan
Yesterday, 5:47 pm
Forum: Scripts
Topic: SymSAT, another SAT-solver-based search package
Replies: 2
Views: 196

Re: SymSAT, another SAT-solver-based search package

Working with this a little further, I coded up the kind of search I really intended this for (and was working on before I decided I needed a better API), which is hexagon grid colorings using "triomino" constraints. These are constraints on mutually adjacent triples of hexagons that may be realized ...
by pcallahan
January 23rd, 2021, 5:12 pm
Forum: Website Discussion
Topic: Suggested LifeWiki edits
Replies: 246
Views: 73082

Re: Suggested LifeWiki edits

GUYTU6J wrote:
January 23rd, 2021, 6:17 am
there is Callahan's B2o/S2m34, too, that seems to be page-worthy.
Thanks for the plug! I would add that the above link works with LifeViewer (in case anyone missed this). I converted my old text write-up for that post and I think it turned out well.
by pcallahan
January 23rd, 2021, 3:33 pm
Forum: General Discussion
Topic: General SAT solver discussion thread?
Replies: 0
Views: 59

General SAT solver discussion thread?

When I look at old Forum postings, I can see there is a lot of interest in SAT solvers for Life and other CA searching, though I don't see a general thread for discussing ideas of how to get the most effective use of SAT solvers. I'd like to start one, though I'm happy to move my question to an exis...
by pcallahan
January 21st, 2021, 12:57 pm
Forum: General Discussion
Topic: Thread for basic questions
Replies: 2383
Views: 678351

Re: Thread for basic questions

I'll let some volunteer finish this one. There are several possibilities that could work: - Connect the left end of the top wall to either of the diagonal walls. - Connect the top wall to its mirror image. - Connect the upper-left diagonal wall to its mirror image. Thanks. I'm set up to explore oth...
by pcallahan
January 21st, 2021, 1:34 am
Forum: General Discussion
Topic: Thread for basic questions
Replies: 2383
Views: 678351

Re: Thread for basic questions

I don't recognize it. It's statorless though! Maybe there's a way to connect it to the parts on the statorless P3? Here's another p3 agar. The blocks showed up because I specified some stators, but obviously they can be removed. x = 36, y = 36, rule = B3/S23:T36,36 # [[ GPS 3 ]] 12b3o15b3o$7bob3o13...
by pcallahan
January 21st, 2021, 12:20 am
Forum: General Discussion
Topic: Thread for basic questions
Replies: 2383
Views: 678351

Re: Thread for basic questions

How did Life enthusiasts find conduits in the old days? Based on some of the early conduits (e.g. Fx77 and Bx125) and the rarity of transparent reactions, it seems like a significant fraction of early conduit-makers' time was spent placing blocks in various places and hoping that it would cause the...
by pcallahan
January 20th, 2021, 11:12 pm
Forum: General Discussion
Topic: Thread for basic questions
Replies: 2383
Views: 678351

Re: Thread for basic questions

Does this p3 agar have a name? I didn't look very hard, but I can find agars and p3 oscillators, but not p3 agars. It came up while testing my SAT-based search program. x = 48, y = 48, rule = B3/S23:T48,48 # [[ GPS 3 ]] 7bo2bo8bo2bo8bo2bo8bo2bo$ob2obo6bob2obo6bob2obo6bob2obo$7bo2bo8bo2bo8b o2bo8bo2b...
by pcallahan
January 20th, 2021, 9:28 pm
Forum: Scripts
Topic: SymSAT, another SAT-solver-based search package
Replies: 2
Views: 196

Re: SymSAT, another SAT-solver-based search package

As an addendum, I extended the definition of templates a little so you can associate extra variables with cell constraints. E.g. these clauses # stator is true iff two consecutive live generations stator$ <- G O ~stator$ <- ~G ~stator$ <- ~O assign a new "stator" truth value to each cell in each gen...
by pcallahan
January 19th, 2021, 8:15 pm
Forum: Scripts
Topic: SymSAT, another SAT-solver-based search package
Replies: 2
Views: 196

SymSAT, another SAT-solver-based search package

[Note: immediately after posting I found that "GridSAT" is already in use, so I hastily changed the name though not the repo. I probably should have put more thought into a name. SymSAT reflects both the importance of symmetry and the use of symbols in place of DIMACS numerical values.] Motivation: ...
by pcallahan
January 1st, 2021, 6:25 pm
Forum: Patterns
Topic: PotY 2020 Nomination Thread
Replies: 35
Views: 1374

Re: Nominations for the pattern of 2020

When nominating a pattern, please provide a link. If there isn't a satisfactory link, you can make a short post that describes and includes the pattern(s) which we can link to from the master list. Also, in my opinion the credits for the p28 glider gun should probably mention Paul Callahan (discove...
by pcallahan
December 29th, 2020, 6:14 pm
Forum: General Discussion
Topic: 50th anniversary of Martin Gardner's article
Replies: 5
Views: 1600

Re: 50th anniversary of Martin Gardner's article

This article by Siobhan Roberts about Life's 50th anniversary went online yesterday, and is apparently in the print edition of the New York Times today. Good article. It completely escaped my notice if it was on the NYT online front page yesterday. I liked the selection of quotes too. I'm always in...
by pcallahan
December 20th, 2020, 10:29 pm
Forum: The Sandbox
Topic: If anyone wants to tile their home on a cellular automata theme
Replies: 0
Views: 174

If anyone wants to tile their home on a cellular automata theme

...for instance, you could tile a bathroom wall with black and white tiles as your favorite Life pattern, or as a still life (keeping it honest, since after all, the ceramic tiles won't be changing) (or a sequence of generations of a 1D CA like rule 110). I was trying to find a robotic solution for ...
by pcallahan
December 15th, 2020, 6:57 pm
Forum: Website Discussion
Topic: Pattern viewer for forum threads
Replies: 1784
Views: 485985

Re: Pattern viewer for forum threads

A bit difficult (they're stored as rhombi IIRC) but nothing impossible if rowett takes a look at the suggestions buried by the other suggestions in this thread. You can do these rotations as linear transformations while keeping the integer coordinates. I have done this with rhombuses, applying a 12...
by pcallahan
December 15th, 2020, 4:41 pm
Forum: Website Discussion
Topic: Pattern viewer for forum threads
Replies: 1784
Views: 485985

Re: Pattern viewer for forum threads

This is a really low priority feature request, but it would be nice to have.

I noticed that for hexagonal CAs, rotate partly works, but it's just the transformation of 90° rotations, and some of the rotations change the pattern neighborhoods. How hard would it be to have true 60° rotation?
by pcallahan
December 14th, 2020, 1:52 am
Forum: Other Cellular Automata
Topic: Hex rule B2o/S2m34: 1997 write-up with viewable patterns
Replies: 9
Views: 675

Re: Hex rule B2o/S2m34: 1997 write-up with viewable patterns

Another strategy that can work in some cases is symmetrizing, or more generally using additional copies of the original rotor in place of stabilizers at other periods. Oh, cool! I can use this approach to fix up my p43 gun so it is no longer p86. x = 35, y = 39, rule = B2o/S2m34H o$bobo$b3o10b2o$2b...
by pcallahan
December 13th, 2020, 1:11 pm
Forum: Other Cellular Automata
Topic: Hex rule B2o/S2m34: 1997 write-up with viewable patterns
Replies: 9
Views: 675

Re: Hex rule B2o/S2m34: 1997 write-up with viewable patterns

BTW how far is the rule from being omniperiodic? Catagolue has recorded a large amount of oscillators at even periods, and the original write-up describes several low prime periods. I notice I was careful in the writeup to list "principal oscillation". I am not sure there is any way to eliminate th...
by pcallahan
December 7th, 2020, 10:40 am
Forum: Scripts
Topic: Logic Life Search
Replies: 215
Views: 96989

Re: Logic Life Search

Question: Why does SAT solver behave so badly in normal searches? I mean, it takes 143s to rule out the existence of a 15x8 c/3 spaceship in LeapLife. Macbi may have some other thoughts, but it's unrealistic to expect a SAT solver to do a better job all the time. In fact, I'm amazed they work so we...
by pcallahan
December 6th, 2020, 1:23 am
Forum: Other Cellular Automata
Topic: Using a SAT solver to generate periodic hex still lifes
Replies: 10
Views: 516

Re: Using a SAT solver to generate periodic hex still lifes

[Note: I keep updating the red and blue indicators in the first image. I think I finally have the matching conditions right. It is easier to see with convex and concave boundaries but I don't have an easy way to do that.) I was able to generate some more complex forms of periodicity (and I'm not sur...
by pcallahan
November 30th, 2020, 8:19 pm
Forum: Other Cellular Automata
Topic: Hex rule B2o/S2m34: 1997 write-up with viewable patterns
Replies: 9
Views: 675

Re: Hex rule B2o/S2m34: 1997 write-up with viewable patterns

A p60 with a p3 and p20 part, sorry if this is already known. Look at the section "other guns" in the original post, and you'll see the same p20 part used to make a gun. I don't remember a lot about the specific oscillators I found, but they were pretty easy to generate from small random seeds that...
by pcallahan
November 30th, 2020, 3:04 pm
Forum: Scripts
Topic: Logic Life Search
Replies: 215
Views: 96989

Re: Logic Life Search

Another question, mostly for Macbi, and maybe this has been discussed before. Has anyone implemented a SAT approach for a Bellman-like search? I don't know the Bellman algorithm, but I can see how SAT would be a great way to express a still-life region combined with a more variable region representi...
by pcallahan
November 30th, 2020, 2:30 am
Forum: Other Cellular Automata
Topic: Using a SAT solver to generate periodic hex still lifes
Replies: 10
Views: 516

Re: Using a SAT solver to generate periodic hex still lifes

Never mind. I messed up my own rule format, since my script needs to express all the 3 and 4 cell shapes explicitly. Here is the command to generate the SAT problem for a B2o/S2m34H still life. (I'll update the other post too.) python hexsat.py 64 64 02o 2m3o3p3mr3ml4o4m4p > sat.txt ./solvers/lingel...
by pcallahan
November 30th, 2020, 1:30 am
Forum: Other Cellular Automata
Topic: Using a SAT solver to generate periodic hex still lifes
Replies: 10
Views: 516

Re: Using a SAT solver to generate periodic hex still lifes

If you can get a timing on generating a similar still life in LifeFind, I'm curious. LifeFind took 45s to find a 64x64 unconstrained SL in Life. Regular Life or the hex rule? For regular life, the SAT solver (lingeling) can find a solution in 0.9s: ... c 0.646 71% simplifying c 0.264 29% search c =...
by pcallahan
November 30th, 2020, 1:01 am
Forum: Other Cellular Automata
Topic: Using a SAT solver to generate periodic hex still lifes
Replies: 10
Views: 516

Re: Using a SAT solver to generate periodic hex still lifes

free software Isn't Wolfram Language free? Eh. Not sure. As I explained, I have a different goal here. BTW, it just took a few hours to code up the Python part, and this was after putting the effort into exploring some other possibilities (mostly https://conwaylife.com/wiki/Logic_Life_Search, which...
by pcallahan
November 30th, 2020, 12:16 am
Forum: Other Cellular Automata
Topic: Using a SAT solver to generate periodic hex still lifes
Replies: 10
Views: 516

Re: Using a SAT solver to generate periodic hex still lifes

LifeFind[32, 32, 1, "Agar" -> True, "Rule" -> "B2o/S2m34H"] should do the work, I think. Is this LifeFind? https://github.com/AlephAlpha/LifeFind If I need Mathematica for it, that's a non-starter. I typically limit myself to free software or what I write myself. Also, my goal is to develop a SAT a...
by pcallahan
November 29th, 2020, 11:54 pm
Forum: Other Cellular Automata
Topic: Using a SAT solver to generate periodic hex still lifes
Replies: 10
Views: 516

Re: Using a SAT solver to generate periodic hex still lifes

No offense... but isn't this exactly what LifeFind does? LifeFind also supports hex INT and Generations rules. There are a lot of different search programs out there. I intend to run more custom searches that may not fit into CA rules as neatly, so it is more proof of concept (for me, because other...