Intro Flashcards
what is a constructive solver?
>>> what is the search trajectory?
constructive solver?
works by extending an empty solution
>>> search trajectory is correct but incomplete solutions
what is an iterative improvement method?
>>> what is the search trajectory?
iterative improvement method:
works by improving solution
>>> complete but incorrect solutions
what are 4 classes of NP problems?
NP-problems:
- P - solvable in polynomial time
- NP - solvable and any solution can be verified in polynomial time
- NP-complete: belongs to class NP and any other problem in NP can be reduced to this problem in polynomial time
- NP-hard: problem is at least as hard as any other problem in NP-complete but solution cannot necessarliy be verified in polynomial time
what is lamarckism? how does it relate to EC?
lamarckism: acquired features can be inherited from parents to offspring
>>> turns out not to be true in biological evolution
>>> but we can use it in EC
what are the two competing forces in evolution?
competing forces in evolution
- increasing population diversity by variation
> mutation and recombination
>>> push towards novelty
- decreasing population diversity by selection
> selection of parents/ survivors
>>> push towards quality
selection operators act on …?
variation operators act on….?
selection operators operate on population level
variation operators act on individual level
what are 4 possible termination conditions?
- reaching some fitness level
- reaching maximum amount of generations
3 reaching minimum level of diversity
- reaching some specific number of generations without fitness improvement
why are selection operators independent of representation?
they only use the fitness value
is it worth expending effort on smart initialization?
depends:
> can be good if solution/ methods exist
> may not be necessary, EA will catch up quickly
global optima: deterministic vs heuristic approaches
deterministic:
> guarantee to find global optimum
> may have bounds on runtime, usually polynomial
heuristic:
> generate and test approach
> no guarantee that solution is global optimum
> no bounds on runtime