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Questions tagged [monte-carlo-tree-search]

This tag should be used for questions about the MCTS algorithm (how/why it works, potential applications, enhancements, combinations with other algorithms, implementation, etc.)

3
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2answers
87 views

Rollout algorithm like Monte Carlo search suggest model based reinforcement learning?

From what I understand, Monte Carlo Tree Search Algorithm is a solution algorithm for model free reinforcement learning (RL). Model free RL means agent doesnt know the transition and reward model. ...
1
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2answers
124 views

Is Monte Carlo Tree Search appropriate for problems with large state and action spaces?

I'm doing a research on a finite-horizon Markov decision process with $t=1, \dots, 40$ periods. In every time step $t$, the (only) agent has to chose an action $a(t) \in A(t)$, while the agent is in ...
2
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1answer
32 views

Why do neural nets and machine learning tend to work well with MCTS, but not with regular Minimax game-playing AI?

I've often heard MCTS grouped together with neural nets and machine learning. From what I gather, MCTS uses a refined intuition (from maching learning) to evaluate positions. This allows it to better ...
1
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1answer
52 views

Any interesting ways to combine Monte Carlo Search with the standard Minimax/Alpha-beta algorithms?

I've been working on a game-playing engine for about half a year now, and it uses the well known algorithms. These include minimax+alpha-beta pruning, iterative deepening, transposition tables, etc. ...
4
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1answer
44 views

How does Hearthstone AI deal with random events

I want to learn a lot about the AI of CCG, such as Hearthstone. And now I have known one of the main algorithms that used in this kind of games, MCTS. It analyses the most promising moves, and expands ...
1
vote
1answer
70 views

Weighted move rating for AI

My AI (for the card game schnapsen) currently calculates every possible way the game could end and then evaluates the percentage of winning for every playable card / move. The calculation is done ...
1
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1answer
31 views

Is it meaningful to give more weight to the result of monte carlo search with less turn win?

I'm programming on Connect6 with MCTS. Monte Carlo Tree Search is based on random moves. It counts up the number of wins in certain moves. (Whether it wins in 3 turns or 30 turns) Is the move with ...
2
votes
1answer
49 views

Should I use Monte Carlo or a classifier for this Decision Making problem?

I want to build a model to support decision making for loan insurance proposal. There are three actors in the problem: a bank, a loaner applicant (someone who ask for a loan) and a counselor. The ...
6
votes
3answers
136 views

Would AlphaGo Zero become perfect with enough training time?

Would AlphaGo Zero become theoretically perfect with enough training time? If not, what would be the limiting factor? (By perfect, I mean it always wins the game if possible, even against another ...
4
votes
1answer
165 views

Algorithms for games with very high branching factors (Connect6)

Connect6 is an example of a game with a very high branching factor. It is about 45 thousand, dwarfing even the impressive Go. What algorithms can you use on games with such high branching factors? I ...
3
votes
1answer
215 views

Monte Carlo Tree Search Expansion Phase

I'm confused regarding a specific detail of MCTS. To illustrate my question, lets take the simple example of tic-tac-toe. After the selection phase, when a leaf node is reached, the tree is expanded ...
7
votes
2answers
166 views

Does Monte Carlo Search (specifically used by AlphaZero) Qualify as Machine Learning?

To the best of my understanding, Monte Carlo Search is an alternative method to Minimax for searching a tree of nodes. It works by choosing a move (generally the one with the highest chance of being ...
12
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5answers
3k views

How do I choose which algorithm is best for something like a checkers board game?

I am currently new to artificial intelligence but I am very intrigued by it. I am currently researching three algorithms, namely: Minimax, Alpha-beta pruning and Monte Carlo tree search. As you may ...
6
votes
3answers
634 views

Why does Monte Carlo work when a real opponent's behavior may not be random

I am learning about Monte Carlo algorithms and struggling to understand the following: If simulations are based on random moves, how can the modeling of the opponent's behavior work well? For ...
-3
votes
1answer
112 views

Are recent advances in machine learning really “artificial” intelligence, or merely brute force and human design?

It sounds like people boast of something being "artificial" about machine learning when actually people boast that humans implemented algorithms like e.g. Monte Carlo Search (MCST) etc. I think the ...
3
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1answer
469 views

When to expand and when to simulate in MCTS? (Monte Carlo Tree Search )

In MCTS, we start at root node R. Then we select some leaf node L. And we expand it by one or more child nodes and simulate from the child to end of game.image link My question is when to expand? and ...
1
vote
1answer
103 views

How to estimate the AI player's strength in multiplayer game?

I have implemented multiple MCTS based AI players for the Love Letter game (rules). It is a 2-4 players zero sum card game where players make alternating moves. I am struggling with how to properly ...
3
votes
1answer
258 views

Which Reinforcement Learning algorithms are efficient for episodic problems?

I have some episodic datasets extracted from a turn-based RTS game in which the current actions leading to the next state doesn’t determine the final solution/outcome of the episode. The learning is ...
3
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1answer
273 views

AlphaZero chess algorithm, Monte Carlo search

Recently, DeepMind's AlphaZero chess algorithm did better than the prior best chess software Stockfish. I read an arxiv paper about it but I'm not sure if: is there a value given for each piece (e.g. ...
2
votes
1answer
67 views

Do AIs based on MCTS start each game from scratch?

AIs that rely on MCTS - like AlphaGo - create their decision tree as the game progresses. Do they start from scratch each game and build a new tree or do they keep the tree and grow it from game to ...
4
votes
1answer
120 views

Determinization step in Information Set Monte Carlo Tree Search

After reading this paper about Monte Carlo methods for imperfect information games with elements of uncertainty, I couldn't understand the application of determinization step in author's ...
1
vote
1answer
305 views

Can we use MCTS/UCT without a generative model?

From what I have understood reading the UCT paper "Bandit based monte-carlo planning", MCTS/UCT requires a generative model. Does it mean, in case there is no generative model of the environment, we ...
5
votes
1answer
392 views

MCTS: Terminal (leaf) nodes in selection step

In Monte Carlo Tree Search: What does one do when the Selection step selects a node that is a Terminal state, i.e. a won/lost state (it's by definition a leaf node)? Expansion/Simulation is not in ...
1
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1answer
71 views

How do you generate the transition probabilities of a non-trivial MDP?

I understand an MDP (Markov Decision Process) model is a tuple of $\{S, A, P, R \}$ where: $S$ is a discrete set of states $A$ is a discrete set of actions $P$ is the transition matrix ie. $P(s' \mid ...
10
votes
1answer
327 views

Monte Carlo Tree Search: What kind of moves can easily be found and what kinds make trouble?

I want to start with a scenario that got me thinking about how well MCTS can perform: Let's assume there is a move that is not yet added to the search tree. It is some layers/moves too deep. But if we ...
5
votes
1answer
127 views

How do I know when to use which Monte Carlo method?

I'm a bit confused with extensive number of different Monte Carlo methods such as: Hamiltonian/Hybrid Monte Carlo (HMC), Dynamic Monte Carlo (DMC), Markov chain Monte Carlo (MCMC), Kinetic Monte ...
15
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1answer
1k views

How does “Monte-Carlo search” work?

I have heard about this concept in a Reddit post about Alpha Go. I have tried to go through the paper and the article, but could not really make sense of the algorithm. So, can someone give an easy-...