2. What is CGP?
CGP is a form of Automatic computer program
Evaluation (GP)
Developed be Miller and Thompson 1997.
Inspired from evaluation of digital circuit.
Capable of encoding computer programs, electronic
circuits, neural network.
3. Representation
Programs are represented as directed acyclic graphs
which are encoded in the form of a linear string of
integer
Genes are
Address in data (Connection genes)
Address in a function lookup table (Function genes)
Address in output data (Output genes)
Genotype is string of integers.
Eg. 0 0 1 1 0 0 1 3 1 2 0 1 0 4 4 2 5 4 2 5 7 3
7. Genotype-to-Phenotype mapping
Result from the decoding of a genotype is called
phenotype.
Many-to-one genotype to phenotype mapping.
Some genes in phenotype can be ignored
9. Evolution of CGP Genotypes
Most CGP system use only mutation.
Point-mutation
Mutation rate
Gene location is change with other valid random value.
Function with other random valid address of function.
Input gene value with valid output from any other node
or terminal node value.
Output with address of output of other node in
genotype or terminal node value.
Crossover
12. Cont’d
An offspring is always chosen if it is equal as fit or has
better fitness than the parent.
13. Genetic Redundancy
Node redundancy
Genes those are not used in fitness calculation.
Functional redundancy
Sub-function that actually may be implemented with fewer
nodes
bloat
Input redundancy
Node functions are not connected to some of the input node
Neutrality
Adaptive evolution may cross regions with poor fitness in
fitness landscape.
