Biological Inspiration and Search Spaces
From Biology to Algorithms
Natural Selection as Search
Evolutionary algorithms borrow ideas from biological evolution: variation creates diversity, selection favors useful traits, and inheritance carries improvements forward. In optimization, the objective function plays the role of the environment.
Important Analogy
A candidate solution is like an organism, and its fitness is like reproductive success in a given environment.
Search Space
The search space is the set of all possible candidate solutions. Each point in the search space corresponds to one possible design, parameter vector, program, or structure.
Mapping Biology to Computation
| Biology | Computation |
|---|---|
| Organism | Candidate solution |
| Genome | Encoded representation |
| Fitness | Objective score |
| Mutation | Random perturbation |
| Selection pressure | Preference for better solutions |
How Evolutionary Search Proceeds
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1
Step 1: Define how a solution is represented.
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2
Step 2: Define how to evaluate quality.
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3
Step 3: Define mutation or recombination operators.
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4
Step 4: Choose a selection mechanism.
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5
Step 5: Iterate until time, quality, or convergence limits are reached.
Exploration and Exploitation
Good evolutionary search balances exploration, which discovers new areas of the search space, with exploitation, which refines promising areas. Mutation promotes exploration, while selection promotes exploitation.
In evolutionary computation, what does the objective function represent?
The objective function defines how candidates are scored.
Correct answer: The environment's scoring rule
What is the search space in one phrase?
It contains every solution the algorithm might consider.
Correct answer: The set of all possible candidate solutions.
Which process mainly increases diversity in a population?
Mutation introduces variation and new candidate types.
Correct answer: Mutation
Modeling Reminder
Biological metaphors are useful, but algorithms are judged by computational performance, not biological realism.