Week 4 — Local Search
The constant-memory optimizer — climb the best local neighbor, stop when stuck. Why it fails and beam/search/variants fix it
- Hill Climbing and Local Search
The constant-memory optimizer — climb the best local neighbor, stop when stuck. Why it fails and beam/search/variants fix it
- Solution Space Search and the SAT Landscape
Stop searching states, start searching solutions — synthesis vs perturbation, the SAT landscape, and why ridge edges trap hill climbers
- Stochastic Hill Climbing and Simulated Annealing
Accept bad moves on purpose — the sigmoid rule, the temperature dial, and the metallurgy metaphor that escapes local optima
- Genetic Algorithms
Evolve a population of solutions — roulette selection, crossover, mutation, and why losing diversity kills the search
- Genetic Algorithms for TSP — Representations and Crossover
Why naive crossover breaks tours — cycle crossover, PMX, order crossover, adjacency encoding, and the ordinal trick that makes any cut safe
- Ant Colony Optimization
Simple ants, collective intelligence — pheromone trails solve TSP without any ant knowing the tour exists