Heat

This blinker has heat 4

The heat of an oscillator or spaceship is the number of cells that change state in each generation; the value provided is often an average across all generations. For example, the heat of a blinker is 4 because 2 cells are born and 2 die every generation – the four cells that change state each generation are highlighted in green to the right. Similarly, the heat of a lightweight spaceship is 11 because 9 cells change in its odd-numbered generations (3 cells die and 6 are born) and 13 cells change in its even-numbered generations (8 cells die and 5 are born), for an average of 11 cells changing per generation.

For a period n oscillator with an r-cell rotor, the heat is at least 2 r / n and no more than r (1 - (n mod 2) / n). For n = 2 and n = 3 these bounds are equal.

Temperature is a metric of heat in proportion to the total number of active cells.

Oscillators with low heat

The following table lists the nontrivial oscillators with the lowest known heat for their respective periods. Values proven to be minimal are highlighted in green. Burloaferimeter is the only known oscillator with a heat of less than 2, although a heuristic argument suggests that high-period oscillators with heat arbitrarily close to 4/3 exist.

Period	Heat	Examples
2	2	beacon, spark coil
3	2	stillater, cuphook, 1-2-3
4	2	Gray counter, 1-2-3-4
5	2	technician
6	2	$rats
7	10/7 ≈ 1.43	burloaferimeter
8	2	R2-D2
9	26/9 ≈ 2.89	43P9, 45P9
10	16/5 = 3.2	39P10
11	32/11 ≈ 2.91	52P11
12	3	60P12
13	32/13 ≈ 2.46	57P13
14	2	44P14
15	4	54P15, 65P15
16	7/2 = 3.5	37P16
17	66/17 ≈ 3.88	54P17.1
18	34/9 ≈ 3.78	Merzenich's p18
19	636/19 ≈ 33.47	cribbage
20	5	58P20
21	148/21 ≈ 7.05	58P21
22	34/11 ≈ 3.09	champagne glass
23	412/23 ≈ 17.91	55P23
24	25/4 = 6.25	58P24
25	372/25 = 14.88	36P25
26	222/13 ≈ 17.08	87P26
27	208/27 ≈ 7.70	73P27

External links

• Heat at the Life Lexicon
• Golly script to calculate heat of spaceships and oscillators