* {{LinkForumThread|title=Re: (Engineered) diehards|p=144151|author=Pavel Grankovskiy|date=April 12, 2022}} (analysis of the tetrational diehard's total runtime)
* {{LinkForumThread|title=Re: (Engineered) diehards|p=144151|author=Pavel Grankovskiy|date=April 12, 2022}} (analysis of the tetrational diehard's total runtime)
[[Category:Methuselahs]]
[[Category:Gliderless methuselahs]]
[[Category:Gliderless methuselahs]]
Revision as of 05:32, 1 December 2023
This article is a stub. You can help LifeWiki by expanding it.
Beginning in early 2022, there has been considerable interest in constructing artificial diehards within small bounding boxes. On March 1, Dean Hickerson shared a 9044-tick 32 × 32 diehard in a private email to Dave Greene. After a complex series of interactions between an active reaction and various still lifes, a single lightweight spaceship is produced which eventually catches up to and collides with 30P5H2V0, producing a single loaf. Finally, an even slower 25P3H1V0.1 eventually collides with the loaf, destroying both of them.[2] On March 6, more optimized versions using different combinations of spaceships (including the especially slow copperhead) were shared, including a 14,010-tick diehard at 32 × 32 and an 18,477-tick diehard at 36 × 36.[3]
Although Hickerson's results were not initially posted publicly, a forum thread was coincidentally started a few weeks later dedicated to diehards, including engineered ones.[4] On March 31, Pavel Grankovskiy posted a 50,716-tick diehard in which a Simkin glider gun and pulse-dividing glider reflectors are used to slowly eat through a series of tubs. Although significantly larger than Hickerson's constructions at 90 × 86, Grankovskiy's 50,716-tick diehard does not use the "spaceship-chasing" technique, meaning that throughout its evolution, the pattern only slightly exceeds its initial bounds. Using spaceship-chasing, however, the pattern's lifespan can be increased by an order of magnitude to 518,476 ticks without further increasing the bounding box.[5]Jiahao Yu optimized the bounding box of both of these patterns to 87 × 86,[6] as shown below.
Using a sawtooth allows for the creation of extremely long-lasting diehards. On April 7, 2022, Pavel Grankovskiy successfully constructed a diehard using a sawtooth an expansion factor of 121. The pattern fits within a bounding box of 99 × 101 (just barely meeting the 10,000-cell restriction specified in the original post[4]) and lasts approximately 2.280624 × 10870 generations.[7] Further optimizations, with the help of toroidalet,[8] Dean Hickerson,[9]EvinZL,[10]Rocknlol,[11] and Adam P. Goucher[12] increased its lifespan to ~1.33616 × 101443 ticks[13] and decreased its bounding box to 94 × 98.[14]
On April 9, Grankovskiy posted a concept for a pattern whose lifespan is measured via tetration, the next hyperoperator after exponentiation. Originally posted in the form of a methuselah,[15] the diehard version was completed on April 11.[16] With optimization by Tanner Jacobi[17] and toroidalet,[18][19] its lifespan is somewhere between 1510 and 1610 ticks.[20]
On July 9, 2023, EvinZL proposed adding loaf-making fuse to increase the lifespan of the methuselah by extending power tower length,[21] based on the original idea of Tanner Jacobi.[22] In a flurry of activity that followed after, toroidalet, Adam P. Goucher, Pavel Grankovskiy and EvinZL pushed the number of loaves from 15[23] to approximately 3.52 × 1048[24], with the latter improvement based on idea by Adam P. Goucher to use gliders from exponential part of diehard to ignite the fuse.[25] This was subsequently improved to 1.1 × 101046[26][27].
109 × 91 tetrational diehard with a lifespan exceeding 10104610. (click above to open LifeViewer) RLE:herePlaintext:here
Double-tetrational designs
On 15th September 2023, Tim Coe and b3s23love increased the height of the tetrational tower from 1.1 × 101046 to 1218.46 × 101059. The following day, Tim Coe further improved this height to 121121121121498, so the height of the tetrational tower is itself a tetrational tower. This was subsequently further improved by Tim Coe, toroidalet, EvinZL, and b3s23love, culminating in a height of 1211211211211211211211211211356648129958673823266622201465466300 as of the 28th September 2023. The overall lifespan of the diehard exceeds 111111, or 11^^^3 in Knuth's up-arrow notation. More recent designs have further improved lifespans, with the current record holder taking 17^^^3 generations to die out entirely.
Timetable
In many cases, several incremental record-breaking improvements were made inside 24 hours. In the following table, the record-breaking pattern for each day is listed (with each day beginning and ending at UTC 0:00).[28]
Date
Lifespan
Bounding box size
Bounding box cells
Contributor(s)
2022-02-21
2474
32×32
1024
Charity Engine
2022-03-01
9044
32×32
1024
Dean Hickerson
2022-03-06
14010
32×32
1024
Dean Hickerson
2022-03-31
518476
90×86
7740
Pavel Grankovskiy
2022-04-01
518476
87×86
7482
Jiahao Yu
2022-04-07
2.28 × 10^870
99×101
9999
Pavel Grankovskiy
2022-04-09
1.77 × 10^1295
94x96
9024
Pavel Grankovskiy, toroidalet, Rocknlol
2022-04-10
1.476 × 10^1595
94×99
9306
Pavel Grankovskiy, Dean Hickerson
2022-04-11
11 ^^ 10
105×95
9975
Pavel Grankovskiy
2022-04-13
11 ^^ 11
108×92
9936
toroidalet, Pavel Grankovskiy
2022-04-14
11 ^^ 13
109×91
9919
Pavel Grankovskiy, toroidalet, Tanner Jacobi
2023-07-17
121 ^^ 15
110×90
9900
toroidalet, Pavgran
2023-07-18
121 ^^ (4.98 × 10^27)
111×90
9990
Pavel Grankovskiy, toroidalet, EvinZL, Adam P. Goucher
2023-07-19
121 ^^ (5.94 × 10^54)
109×91
9919
Pavel Grankovskiy, May13, toroidalet, EvinZL, Adam P. Goucher
Pavel Grankovskiy (April 12, 2022). Re: (Engineered) diehards (discussion thread) at the ConwayLife.com forums (analysis of the tetrational diehard's total runtime)
