Genetic speed optimization

[MartinPontius]

Related Issue / Discussion:

Fixes Issues 52North/WRT-Issues#16, 52North/WRT-Issues#20

Changes:

• New classes SpeedCrossover, RandomPercentageChangeSpeedMutation and GaussianSpeedMutation
• Modified classes Config, CrossoverFactory, MutationFactory and FromGeojsonPopulation

Further Details:

Summary:

Crossover:
The new class SpeedCrossover allows to swap speed values for pairs of points between two parents. The candidate pairs are identified by checking if their distance is below a given threshold. This approach ensures that speed values are not swapped for unrelated points.

Mutation:
There are two new mutation classes which mutate ship speed:

1. RandomPercentageChangeSpeedMutation: Speed values are mutated by randomly adding or subtracting a percentage. The percentage is randomly chosen between 0 and a fixed maximum percentage (currently 20 %).
2. GaussianSpeedMutation: Speed values are updated by drawing random samples from a Gaussian distribution. The mean value of the distribution is currently set to half of the maximum boat speed. The standard deviation is set to 1/6 of the maximum boat speed.

The factory classes and the Config class are updated accordingly to allow configuring the new mutation and crossover operators.

The FromGeojsonPopulation class was updated so that it is possible to provide a number of routes (GeoJSON files) smaller than the specified population size. In these cases, the remaining chromosomes are filled with a copy of the first route. This change is especially important for a pure speed optimization with fixed waypoints.

Dependencies:

No additional dependencies

PR Checklist:

In the context of this PR, I:

• have (already previously) filled the 52North Contributor License Agreement and received positive feedback on this matter
• have filled the 52North Contributor License Agreement and am waiting for feedback
• provide unit tests embedded in the WRT test framework (WeatherRoutingTool/tests) that allow the simple testing of the new/modified functionalities. All (previous and new) unit tests execute without new error messages.
• ensure that the code formatter runs without errors/warnings
• ensure that my changes follow the WRT’s guidelines for contributing at the time of the contribution

Please consider that PRs which do not meet the requirements specified in the checklist will not be evaluated. Also, PRs with no activities will be closed after a reasonable amount of time.