Life sciences · the experiment
Evolve the AND function
You steer the evolution of circuits made of NAND gates. Take them from NAND to AND, count what it costs in mutations, then change the starting point.
1 · Run one evolution
Your circuit: 10 NAND gates in a fan. It computes NAND; the target is AND.
Beginner
In these circuits, what do almost all mutations do?
Mutate the circuit until it computes AND.
2 · Double the size
Intermediate
According to the article, roughly how many mutations does it take to evolve AND in a fan circuit of 1,000 gates?
Measure it: 500 evolutions per size, as in the article. Find the size that needs twice as many mutations as a 20-gate circuit.
3 · Change the start
Expert
You now start from a chain of gates in which all 2N + 1 wires compute. From 21 to 81 gates, what happens to the number of mutations needed?
Check it: 500 evolutions per size and per start. The figures are medians, reached by half of the evolutions (a few chains stay stuck for a very long time). Find a size where the chain needs at least twenty times fewer mutations than the fan.
4 · What about time?
Expert
From the fan, the article's fit gives about 89 mutations for 10 gates and 7,430 for 1,000 gates. Mutations arrive in proportion to the number of wires: 21 versus 2,001. How long does the big circuit take to reach AND, compared with the small one?
AND evolved
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