Pheromone deposit adds simulated pheromone to paths or edges traversed by artificial ants, increasing the likelihood that later ants choose those edges. section 10.2
Common deposit strategies differ in when pheromone is added and how its amount is calculated:
- Online step-by-step updates deposit pheromone as each ant traverses an edge; ant density uses a constant amount, while ant quantity scales deposits with local edge quality such as Q/dij. section 10.2
- Online delayed updates, also called the ant cycle model, wait until an ant completes its solution, then reinforce the traversed path according to solution quality. section 10.2
- Deposit interacts with evaporation: no evaporation can trap ants in a local optimum, whereas maximum evaporation forces random exploration and can slow convergence. section 10.2
Figure 10.5 Pheromone update methods
Compare the pheromone update methods used to reinforce ant-traversed paths. section 10.2
