Friday, February 8, 2008

DPS906 Lecture 8

E=T-O -- error calculation

Wj = Wj + lr * Ij * E -- new weight calculation

Genetic Algorithm (GA)
- things evolve from other things... including solutions.

Solutions can evolve from other solutions.
- solutions need to be some sort of parameter list (called a string)
- create a gene (one possible solution)
- each gene needs to be evaluated for its fitness

start with initial population of randomly generated solutions(genes)
for the better solutions give them a % chance to be successful
This % chance is called "Relative Fitness"
5 genes
g1 fitness = 5 (relative fitness is 5/15) [0.333]
g2 fitness = 3 (relative fitness is 3/15) [0.533]
g3 fitness = 4 (relative fitness is 4/15) [0.799]
g4 fitness = 1 (relative fitness is 1/15) [0.866]
g5 fitness = 2 (relative fitness is 2/15) [1]

now survival of the fittest pick 5 genes at random by rolling a dice which has values between 0 and 1

next operation is called cross over to form new genes. Then to restart the process.

mutation process... you randomly pick one spot on a gene and change it. You dont want to do mutations very often.

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