particle swarm optimization
**Particle Swarm Optimization (PSO)** is a **population-based optimization algorithm inspired by the social behavior of bird flocks** — particles (candidate solutions) move through the parameter space guided by their own best-found position and the swarm's best-found position.
**How PSO Works**
- **Particles**: Each particle has a position (solution) and velocity in the parameter space.
- **Personal Best ($p_{best}$)**: Each particle remembers its own best position.
- **Global Best ($g_{best}$)**: The best position found by any particle in the swarm.
- **Update**: Velocity is updated as a weighted sum of inertia, attraction to $p_{best}$, and attraction to $g_{best}$.
**Why It Matters**
- **Fast Convergence**: PSO typically converges faster than genetic algorithms for continuous optimization.
- **Few Parameters**: Only tuning parameters are inertia weight, cognitive and social coefficients.
- **Process Optimization**: Well-suited for continuous process recipe optimization with 5-50 parameters.
**PSO** is **a swarm searching for the optimum** — particles collectively exploring the parameter space, sharing information about promising regions.