two class of GA, based on replacement
- Generational genetic algorithm(GGA)
- Steady-state genetic algorithms(SSGA) this one is better than
Replace random
Replace worst
Replace oldest if the oldest is good than the new one that not good
Elitist never be replace because we mark this one is the best it's depend on your parameter (normally n=1) if we set more this test will not be vary in the fitness
============= all of those part are end of one generation or iteration ===============
so next one is Stopping Criteria
there were 2 approaches for stopping criteria:
- First approach
Stop aafter production of definite number of generations (MAXGEN) or number of objective function calls evaluations (MAXNFC/MAXNFE<use this more>) or (rarely used) time (in s/min/hr)
- Second approach
Stop when the improvement in average fitness over two generation is below is below a threshold
GA vs Ad-hoc
In disadvantage
there are two words we should know that is exploration (diversification) การควานหาคำตอบบริเวณกว้าง and exploitation (intensifation) การหาคำตอบบริเวณที่เฉพาะเจาะจง
effects of control parameters
Population size (PS or NP) - typical 50 - 200
Crossover rate (CR or Pc) - typical 0.70 - 0.90
if crossover rate is too high the diverse is low
if crossover rate is too low the search may stagnate due to the lower exploration rate
Mutation rate (MR or Pm) - typical 0.01 - 0.05
Mutation increase the variability of the population.
High level of mutant yield an essentially random search, with may lead to very slow convergence
Low level of mutant
So next we have class experiment
Mutation increase the variability of the population.
High level of mutant yield an essentially random search, with may lead to very slow convergence
Low level of mutant
So next we have class experiment
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