Slow Spaceships

[RakeGuy1246]

I've been wondering "How slow can a spaceship go?" So let's all try to build spaceships with insanely low speeds and see how slow we can get.

[hotdogPi]

Is this supposed to be in the OCA forum, or do you want us to search Conway's Life at c/34, c/35, c/36, etc.? (Because of the way search programs work, ships with many phases are only going to be discovered if they're tiny like the loafer or copperhead.)

[dvgrn]

Is this supposed to be in the OCA forum, or do you want us to search Conway's Life at c/34, c/35, c/36, etc.? (Because of the way search programs work, ships with many phases are only going to be discovered if they're tiny like the loafer or copperhead.)

Or, since the message says "build" rather than "search for", maybe it's okay to just build a slow Demonoid or Orthogonoid. In which case, there's no lower speed limit. As long as you don't mind widening the distance between the pices a little further, you can get the spaceship to go a little slower. Or if you want something really painfully slow, I think you can lengthen a half-baked knightship instead.

A more extensive modification of a half-baked knightship could count to 2^100 before releasing the next signal to move (3, 6).

[cgoler2]

Ane even slower spaceship would be lengthening a camelship.

[dvgrn]

Ane even slower spaceship would be lengthening a camelship.

A camelship (or its more boring but slower cousin, a regular (1,0) offset ship) can't easily be slowed down by nearly as much as an HBK variant can, for a given size. You can't stop and restart the circulating recipe -- too many precisely-timed gliders. So you have to increase the length of the loop the gliders are circulating in, which inevitably increases the bounding box.

Even if you add extra reflectors to fold the loop into a smaller space, it really doesn't get that much slower. Also the recipe gets longer as you have to build more reflectors, until you break down and use more complicated circuitry to re-use part of the recipe many times to build large banks of reflectors.

By contrast, an HBK variant can easily be engineered so that it builds a p256 gun attached to a chain of 325 CC semi-Snarks, as part of its construction process. The final glider from the half-bakery chains starts up that gun, and the output of the 325th semi-Snark triggers a self-destruct sequence that cleans up the whole chain of semi-Snarks and the gun. The technology for this is all known (it's part of the clock component of the 0E0P metacell).

Then that output glider gets split into the signals needed to run the Googol Plus HBK to move it one more (6,3) step.

If a (6,3)c/{a googol and change} isn't slow enough, then keep doubling the period by adding more semi-Snarks, until you've reached whatever crazylarge number you can be satisfied with.

[wwei47]

You can't stop and restart the circulating recipe -- too many precisely-timed gliders.

Freeze-dried salvos?

[dvgrn]

You can't stop and restart the circulating recipe -- too many precisely-timed gliders.

Freeze-dried salvos?

...too many precisely-timed gliders.

Any given single-channel salvo can be freeze-dried, but it's just wildly impractical to do that for an entire circulating recipe -- not least because the recipe gets ten times as long when it has to do the freeze-drying, and then you have to freeze-dry that recipe, which makes it ten times as long again, etc., etc.

So eventually you have to build a universal computer and get it to do the freeze-drying programmatically, to avoid that infinite-regress problem. And there's a reason that nobody has built a universal computer-constructor with circulating memory and lots of programmatically retrievable sub-recipes -- it's just really complicated to get the retrieval system working, and even if it's more efficient than the alternative, it still turns out to be painfully inefficient in practice.

The 0E0P metacell has a circulating recipe, and maybe you could kind of say that it has a couple of programmatically accessible sub-recipes -- just two of them -- the repeated recipes that build the reflector chains in the 0E0P "nucleus", that hold the metacell's DNA. But mostly the recipes in the 0E0P are just executed serially, like every other construction recipe from Gemini and the linear propagator through spiral-growth, Demonoid, Orthogonoid, camelship, loopship, and so on to the Speed Demonoid.

[hotdogPi]

Has anyone tried searching, maybe for 1 minute each, c/13, 2c/13, 3c/13, c/14, 2c/14, 3c/14 (this one has probably already been searched), c/15, etc.? Since the search time is a function of the number of cells in all its periods combined, a c/7 with 100 cells should take as long as a c/28 with 25 cells or even a glide-symmetric c/28 with 50 cells. Given the loafer (20 cells), the copperhead (28 cells, 14 if you take advantage of symmetry), and Rob's p16 (21 cells; it's not a spaceship but could easily have been a c/8), there might be some small ones hiding.

[yujh]

I think it was said that period + 1, time * 2.
Anyways, randoms:

Code: Select all

qfind -r B3/S23 -p 13 -y 3 -s o -w 5
qfind v2.1 by Matthias Merzenich, 3 May 2021
Input: qfind -r B3/S23 -p 13 -y 3 -s o -w 5


Rule: B3/S23
Period: 13
Offset: 3
Width:  5
Symmetry: odd
Queue size: 2^20
Hash table size: 2^20
Minimum deepening increment: 13
Cache memory per thread: 32 megabytes
Number of threads: 1
Starting search
Queue full, depth 9, deepening 13, 131k/159k -> 6.7k/11k
Queue full, depth 11, deepening 24, 131k/171k -> 2.9k/8.1k
Queue full, depth 16, deepening 32, 131k/224k -> 1.8k/8.6k
Queue full, depth 20, deepening 41, 131k/217k -> 966/6.0k
Queue full, depth 26, deepening 48, 131k/270k -> 623/5.7k
Queue full, depth 34, deepening 53, 131k/277k -> 383/5.1k
Queue full, depth 49, deepening 51, 131k/574k -> 344/6.4k
Queue full, depth 59, deepening 54, 131k/338k -> 223/4.9k
Queue full, depth 69, deepening 57, 131k/257k -> 141/3.1k
Queue full, depth 79, deepening 60, 131k/226k -> 119/2.2k
Queue full, depth 87, deepening 65, 131k/240k -> 98/1.7k
Queue full, depth 95, deepening 70, 131k/210k -> 57/1.2k
Queue full, depth 123, deepening 55, 131k/825k -> 40/1.5k
Queue full, depth 142, deepening 49, 131k/633k -> 43/1.0k
Queue full, depth 191, deepening 13, 20k/983k -> 154/2.5k
Search complete.

0 spaceships found.
Maximum depth reached: 221
Longest partial result:

x = 7, y = 16, rule = B3/S23
b2ob2o$3bo$2obob2o$2o3b2o2$3bo$2b3o$b2ob2o$2b3o$2b3o$2bobo$3bo$
3bo$2bobo$3bo$3bo!

I don't think this is a partial anyways, and only this took me about 2 mins. lol
My guess is that boredom people have searched through all speeds they can

[May13]

No c/13o spaceships with a width of 5 cells (via ntzfind):

Code: Select all

x = 71, y = 25, rule = B3/S23
4bo21b2o$3bobo19bo2bo$3bobo19bo2bo18bo5bo$4bo21b2o18bobo3bobo13bo$46bo
bo3bobo12bobo$47bo5bo13bobo$25b4o39bo$24b6o$3b3o18bob2obo$2bo3bo40bo5b
o$2b2ob2o17bob2obo16b3o3b3o13bo$bo5bo16b6o15b2ob2ob2ob2o11bobo$b2o3b2o
17b4o17bob2ob2obo11bo3bo$2b2ob2o39bo2bobo2bo12bobo$2bo3bo15bobo4bobo
14bo7bo$o2bobo2bo13bob2o2b2obo15bo5bo$b2o3b2o16b2o2b2o17bo5bo12b5o$23b
2o4b2o14b2o7b2o10b5o$3bobo17bob4obo14b2o7b2o11b3o$23bo6bo17b2ob2o14bob
o$b2o3b2o17bo2bo16b2ob2ob2ob2o$b3ob3o15bo2b2o2bo15bo7bo$22bo3b2o3bo15b
3ob3o$2b5o$3bobo!
[[ STOP 13 GPS 13 TRACK 0 -1/14 THEME 0 ]]

Edit: after a few minutes of searching, no 2c/13o spaceships with a width of 5 cells (via ntzfind too):

Code: Select all

x = 79, y = 19, rule = B3/S23
25bo$25bo$25bo44bo5bo$2bo45b2o20bo5bo$bobo42bo4bo17b3o3b3o$bob2o41bo4b
o$3b2o41bo4bo16bobobobobobo$23b5o41b3o3b3o$bo20bob3obo40b3o3b3o$b2o19b
o5bo16b3o2b3o18bo3bo$obo21bobo18b2ob2ob2o18bo3bo$obo20b2ob2o42bo5bo$2b
o20b2ob2o20b2o21b2ob2o$o22bobobo17bo6bo19bobo$3bo19bo3bo17bobo2bobo17b
2o3b2o$21bo7bo16b2o2b2o17b2o5b2o$21bo2bobo2bo15bo6bo16bo7bo$44b2o6b2o
17b2ob2o$69bo2bobo2bo!
[[ STOP 13 GPS 13 TRACK 0 -2/14 THEME 0 ]]