Ant Systems

Question 1

Whats the two differences difference between regular AS and MMAS?

Answer 1

As the name implies Min/max ant system has limits on pheromones. The second difference is that only the best solution deposits pheromones. The best solution can either be iteration best or all time best.

Question 2

What the four steps of the AS algorithm as defined on page

Answer 2

1. initialize pheromone levels, typically nearest neighbour path.
2. Initialize ants to random start nodes. Add start nodes to respective ants Tabu list. Construct paths using ACO prob. function which depend on current path.
3. Update pheromone levels for each edge inverse prop. to each ants path length and evaporate previous present pheromones.
4. repeat 2 and 3 until convergence.