Counter-Ant System (CAS): A Simple Way to Learn ACO

Instead of thinking of pheromone as mysterious equations, think of it as counters or votes.

🐜 The Core Idea

Instead of thinking of pheromone as mysterious equations, think of it as counters or votes:

• Each design variable (e.g., each beam) has a set of options (rebar sizes).
• Whenever a safe and feasible solution is built, the chosen options each get +1 vote.
• Old votes gradually fade away (evaporation).

Over many iterations, the options with the most votes rise to the top, guiding the search toward the best design.

🔄 Iterative Learning

At every iteration:

1. Ants build designs based on current votes.
2. Unsafe designs are discarded.
3. Votes decay slightly (forgetting old, possibly wrong choices).
4. Feasible designs add fresh votes.

Over time, the swarm converges to the lightest safe total As across both beams.