Genetic Programming

Evolutionary.TreeGP — Type

Implementation of Koza-type (tree-based) Genetic Programming

The constructor takes following keyword arguments:

populationSize: The size of the population
terminals: A dictionary of terminals with their their corresponding dimensionality
- This dictionary contains (Terminal, Int) pairs
- The terminals can be any symbols (variables), constant values, or 0-arity functions.
functions: A collection of functions with their corresponding arity.
- This dictionary contains (Function, Int) pairs
initialization: A strategy for population initialization (default: :grow)
- Possible values: :grow and :full
mindepth: Minimal depth of the expression (default: 0)
maxdepth: Maximal depth of the expression (default: 3)
mutation: A mutation function (default: crosstree)
crossover: A crossover function (default: subtree)
simplify: An expression simplification function (default: :nothing)
Use mutation and crossover parameters to specify GP-related mutation operation.
Use selection parameter to specify the offspring selection procedure

Evolutionary.Terminal — Type

Terminal

Allowed terminal element types for tree-based genetic programming expressions.

source

Description

The Genetic Programming is a technique of evolving programs, starting from a population of unfit (usually random) programs, fit for a particular task by applying operations analogous to natural genetic processes to the population of programs. It is essentially a heuristic search technique, i.e. searching for an optimal or at least suitable program among the space of all programs^[1].

Auxiliary Functions

Evolutionary.Expression — Type

Julia expression wrapper

source

Evolutionary.randterm — Function

randterm(t::TreeGP)

Returns a random terminal given the specification from the TreeGP object t.

source

Evolutionary.simplify! — Function

simplify!(expr)

Simplify an algebraic expression

source

Base.rand — Method

rand(t::TreeGP, maxdepth=2; mindepth=maxdepth-1)::Expr

Create a random expression tree given the specification from the TreeGP object t.

source

Protected Functions

The following protected operators guard against domain errors (e.g. division by zero, logarithm of zero) so that arbitrary expression trees can be evaluated safely.

Evolutionary.pdiv — Function

Protected division

source

Evolutionary.aq — Function

Analytic quotient

source

Evolutionary.pexp — Function

Protected exponential

source

Evolutionary.plog — Function

Protected natural log

source