Artificial Intelligence and Machine Learning: Unit I(e): Adversarial search

Games with Chance

Adversarial search - Artificial Intelligence and Machine Learning

Games with a certain element of chance are often more interesting than those without chance, and many games involve rolling dice, tossing a coin or something similar.

Games with Chance

Games with a certain element of chance are often more interesting than those without chance, and many games involve rolling dice, tossing a coin or something similar.

- In the real world many situation infront of us are unpredictable. It is also observed in many games.

Example: Dice rolling, backgammon.

- Some time, in the game, imperfect information is available.

Example: Cards, dominose, etc.

- In game with chance, we can introduce probabilities to our search diagrams and calculate minimax solutions as in the normal games.

- We add 1 more level in game tree i.e. the level of chance nodes.

- Chance nodes have as many successors as outcomes of the random element.

- Minimax with element of chance

1) di (i = 1, ..., n) - Outcomes from the chance nodes.

2) P (di) - Probability of di;

3) S (N, di) - Moves from position N for outcome di;

4) If N is MAX : Utility (N) = Σni=1 P(di) maxs ε S(N, di) utility (s)

5) If N is MIN:

Utility (N) = Σni=1 P(di) maxs ε S(N, di) utility (s)

- The utility is not computed by using just the terminal values. Therefore values assigned to win, loss and draw affect the choice of moves.

- Time complexity increases (n outcomes from the chance nodes) to O (bd nd).

- Alpha-Beta pruning is more complicated in this game trees.

Artificial Intelligence and Machine Learning: Unit I(e): Adversarial search : Tag: : Adversarial search - Artificial Intelligence and Machine Learning - Games with Chance


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Artificial Intelligence and Machine Learning

CS3491 4th Semester CSE/ECE Dept | 2021 Regulation | 4th Semester CSE/ECE Dept 2021 Regulation