Lec7 - Genetic Algorithms Flashcards
What is a genetic/evolutionary algorithm?
It is an optimisation algorithm for black-box functions where we have no access to the gradient.
State the 4 concepts from Darwin’s theory about the origin of species.
- Every individual is different, even from the same species.
- Resources are finite: not all individuals will survive (Fight for Survival)
- Individuals with heritable traits better suited to the environment will survive (Natural Selection)
- The survivors pass their heritable traits to their offsprings.
Describe the three main genetic operators which define genetic algorithms.
- Selection Operator:
Selects the solutions that will be reproduced - Cross-over Operator:
Mixes the parents’ genotype - Mutation Operator:
Type and frequency of the variations applied to the genotype after reproduction.
What is a Fitness Function?
The Fitness Function represents the problem we want to solve. Solving the problem means maximising the fitness. Each problem has a different fitness function.
What do the genotype and phenotype represent?
They represent the potential solutions to the problem
What is the role of the selection operator?
Its role is to select the parents for the next generation.
What is elitism in Evolutionary Algorithms?
Elitism:
Keeping in the new generation a fraction of the best individual found so far. We usually fix this fraction to 10%. This ensures that the fitness oft he best individual in the population strictly increases.
What is the role of the Cross-over operator?
Its role is to combine the traits of the parents.
What is the role of the Mutation Operator?
its role is to explore nearby solutions, by mutating a version of the parents based on some probability (eg. on binary strings we randomly generate a number between 0-1 for every bit of the genotype).
