Genetic Programming

Initial Population Generation

Methods for population generation: Grow Full Ramped Half-and-Half

Variety – Genetic Diversity

Genetic ProgrammingThe Grow Method

Trees generated are of a variable size. Labels for nodes at levels less than the maximum depth

are chosen from both the function and terminal sets. Labels for nodes at the maximum depth are chosen

from the terminal set.

/

*

xx

y

+

*

/

x y x y

+

x y

Genetic ProgrammingThe Full Method

Every tree has the same shape and size. Labels for nodes at a depth less than the maximum

depth are chosen from the function set only. Labels for nodes at the maximum depth are chosen from

the terminal set.

+

* -

x y x y

+

*

/

x y x y

Genetic ProgrammingRamped Half-and-Half

Produces trees of various shapes and sizes. Combines both the full and grow methods. An equal number of trees for each depth in the

range of 2 to the maximum depth is generated. For each depth value half the trees will be

generated using the full method and the other half using the grow method.

Produces a diverse population.

Genetic Programming

Ramped Half-and-Half Example

Population size : 30 Maximum Tree Depth : 6

How many trees of each depth will be created?

How many trees will be created using the full method?

How many trees will be created using the grow method?

30 trees

30/ 5 = 6 trees of each depth

5*3 trees generatedusing grow

5*3 trees generatedusing full

Genetic ProgrammingGP Parameters

Population Size Maximum tree Depth Method of Initial Population Generation

Parameters are varied in an attempt to find asolution.

Remember to store the random generator seed foreach run.