Search and Belief-Space Planning › Key Parameters
Michael BrenndoerferJuly 9, 20261 min read
World Models HandbookAll chapters Part 7 of 12Planning and Agency
Search and Belief-Space Planning › Key ParametersOne section · Sections in this chapter3 / 13 ↓
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The key MCTS parameters in this section are:
- n_sims: Number of simulations per planning call. Controls online cost and often improves decision quality, but finite-budget estimates need not improve monotonically.
- c: Exploration coefficient in the tree policy (UCB1 and PUCT). Larger values encourage exploring under-visited branches.
- max_depth: Maximum simulated horizon. Bounds the cost of each simulation and prevents infinite loops.
- prior: PUCT action prior. Concentrates search when informative, but can suppress exploration if overly confident.
- rollout policy: Default policy used inside simulations. A cheap, accurate heuristic can reduce the simulation budget for a chosen quality target, while a biased heuristic can steer estimates in the wrong direction.