Fitness is a Common Lisp genetic programming framework.
evolve is the central function that initiates and runs the evolution process. It returns the final generation along with the fitness, as the output.
Mandatory arguments -
primitives - Primitive functions to be used (eg., if, and, or and not).
actions - User defined functions that operate on the user-defined world.
conditionals - User defined 'sensors' that operate on the user-defined world.
args - A raw list of the arguments that the 'action' functions can take.
fargs - An evaluted list of arguments that the 'action' functions can take.
fitness-function - The fitness function that takes a set of results and returns a fitness.
fitness-p - Predicate function that determines if a fitness has reached 'success' state.
max-tree-depth - Maximum allowed depth of program trees that need to be generated.
Optional arguments -
max-run-count - Maximum number of evolutions to be run.
max-tree-depth - Maximum depth of program trees generated. Default 5.
member-count - Number of programs in each generation. Default 1000.
repeat-var - Number of evaluations needed on each program. Default 60.
copy-percentage - Percentage of programs to evolve by direct copying.
crossover-percentage - Percentage of programs to evolve by crossing over.
program-count - Number of programs to be selected on each round of tournament selection.
All these parameters are defined in wall-follower.lisp, so evolve can simply be run as follows:
> (load "wall-follower.lisp")
> (load "fitness.lisp")
> (evolve primitives actions conditionals args fargs #'fitness-function #'fitness-p)
((OR
(IF
(OR
(IF (E-SENSOR GRID-WORLD CURRENT-CELL) (SW-SENSOR GRID-WORLD CURRENT-CELL)
(OR (NE-SENSOR GRID-WORLD CURRENT-CELL) (N-SENSOR GRID-WORLD CURRENT-CELL)))
(NE-SENSOR GRID-WORLD CURRENT-CELL))
(E GRID-WORLD CURRENT-CELL)
(AND (SE-SENSOR GRID-WORLD CURRENT-CELL)
(OR (SE-SENSOR GRID-WORLD CURRENT-CELL)
(AND (W-SENSOR GRID-WORLD CURRENT-CELL) (N-SENSOR GRID-WORLD CURRENT-CELL)))))
(N GRID-WORLD CURRENT-CELL))
. 35)
> (evolve primitives actions conditionals args fargs #'fitness-function #'fitness-p)
((IF
(OR
(OR (NE-SENSOR GRID-WORLD CURRENT-CELL)
(AND (AND (E-SENSOR GRID-WORLD CURRENT-CELL) (SE-SENSOR GRID-WORLD CURRENT-CELL)) (N GRID-WORLD CURRENT-CELL)))
(S-SENSOR GRID-WORLD CURRENT-CELL))
(W GRID-WORLD CURRENT-CELL) (S GRID-WORLD CURRENT-CELL))
. 44)