ALife.Creatur.Genetics.Code

Encoding schemes for genes.

Coding schemes

data Code a b

An encoding scheme.

Instances

(Show a, Show b) => Show (Code a b)

mkGrayCode :: [a] -> Code a Bool

Constructs a Gray code for the specified values, using the minimum number of bits required to encode all of the values.

If the number of values provided is not a perfect square, some codes will not be used; calling decode with those values will return Nothing. You can find out if this will be the case by calling excessGrayCodes. For example mkGrayCode ['a','b','c'] would assign the code 00 to a, 01 to b, and 11 to c, leaving 10 unassigned. To avoid having unassigned codes, you can repeat a value in the input list so the example above could be modified to mkGrayCode ['a','a','b','c'], which would assign the codes 00 and 01 to a, 11 to b, and 10 to c.

A Gray code maps values to codes in a way that guarantees that the codes for two consecutive values will differ by only one bit. This feature can be useful in evolutionary programming because the genes resulting from a crossover operation will be similar to the inputs. This helps to ensure that offspring are similar to their parents, as any radical changes from one generation to the next are the result of mutation alone.

Encoding and decoding

encode :: Eq a => Code a b -> a -> Maybe [b]

Encodes a value as a sequence of bits.

encodeNext :: Eq a => (Code a b, a) -> [b] -> [b]

decode :: Eq b => Code a b -> [b] -> Maybe a

Returns the value corresponding to a sequence of bits.

decodeNext :: Eq b => Code a b -> [b] -> (Maybe a, [b])

Miscellaneous

asBits :: [Bool] -> String

Convert a list of bits to a string of 0s and 1s.