Trait gas::fitness::FitnessFunction
source · [−]pub trait FitnessFunction<const N: usize, const NSYMS: usize> {
fn run(&self, chromosone: &[Gene; N]) -> Vec<f64>;
fn nscores(&self) -> usize;
fn names(&self) -> Vec<FitnessName> { ... }
fn weights(&self) -> Vec<f64> { ... }
}Expand description
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A FitnessFunction returns a set of fitness scores when passed a chromosone.
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This is implemented as an enum rather than a trait so that we can store them
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inside a const FitnessConfig
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Fitness scores are floating point numbers where a higher number is considered
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better. Negative numbers are allowed, so if you wish to optimize to zero you
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may simply return the negative of the absolute value.
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NaN values are valid scores, and indicate that the score cannot be
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calculated. When comparing scores, any number compared to a NaN is considered
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a tie.
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Implementations: color_count::ColorCount, distance::Distance, weighted_count::WeightedCount
Required Methods
returns a vector of floats where bigger numbers are better. If your fitness function optimizes to 0, remember that 0 is the biggest negative number. NaN is also a valid score, and means that the score cannot be compared and is considered a tie with any other number.
Provided Methods
fn names(&self) -> Vec<FitnessName>
fn names(&self) -> Vec<FitnessName>
provides an [FitnessFunction.nscores] length human readable name for the scores returned. Optional, but useful for debugging
not all games take weights into account, but some do. The vector must be [FitnessFunction.nscores] long. Scores with higher weights are worth weight times as much as nominal scores. Note that the value of the score is irrelevant – scores are never compared with scores in a different position, scores are only compared with the same score on a different candidate. The weight signifies how valuable it is that this particular score on one candidate is higher or lower than the same score on a different candidate.