Pheromone
A pheromone is a chemical or simulated signal whose strength conveys trail preference and influences subsequent route choices.
Optimization Algorithms: AI techniques for design, planning, and control problems
A pheromone concentration is a numerical measure of trail strength assigned to an edge to influence subsequent ant transitions in an ant-colony algorithm.
- How it is used
- Guides probabilistic route choices in ant colony optimization by carrying information from earlier ants to later ones.
- How deep it goes
- Works through edge initialization, transition weighting, evaporation, and cost-based deposits, without deriving the transition formula in the supplied excerpts.
- Examples
- Uses a five-ant shortest-path example and Python code that updates pheromone levels between cities on an open traveling-salesman route.
- What you can do after
- Build it from scratch by weighting feasible transitions with pheromone and distance, then evaporating and depositing trail values after constructed routes.
Grokking AI Algorithms, Second Edition
Pheromone intensity is the numerical strength of a simulated pheromone signal associated with a path in ant colony optimization.
- How it is used
- Guides route selection in ant colony optimization by recording and sharing the influence of paths explored by simulated ants.
- How deep it goes
- Works through equal initialization, probability-based selection, evaporation, and tour-based reinforcement with Python snippets, without pursuing a theoretical proof.
- Examples
- Uses a short-versus-long bridge, a carnival attraction matrix, and Python trail initialization to make changing path strengths concrete.
- What you can do after
- Build it from scratch by initializing trail intensities, using them in next-visit choices, and updating them after tours.
Read how Grokking AI Algorithms, Second Edition explains pheromone →
Related concepts
- pheromone depositproduced by · Pheromone deposit is an ant colony optimization operation that adds simulated pheromone to paths or edges traversed by artificial ants.
- ant colony optimizationused by · Ant colony optimization is a population-based probabilistic optimization technique in which artificial agents use simulated pheromone trails to guide the search for good solutions.
- pheromone updateproduced by · Pheromone update is the modification of simulated trail strengths in ant colony optimization through evaporation and reinforcement based on solution quality.
- stigmergic communicationuses · An indirect communication mechanism in which social organisms influence one another by modifying and sensing their shared environment.
- antproduced by · An ant is a simulated agent in ant colony optimization that explores possible solutions and uses pheromone information to guide solution construction.
- pheromone evaporationconfigured by · Pheromone evaporation is the reduction of pheromone strength over time, weakening the influence of previously favored paths.
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