In MCTS, what do the AI levels correspond to?

by **shedletsky** » 11 Sep 2016, 21:25

Is it:

1. The number of ply searched
2. Some measure of the quality of the heuristics
3. Some measure of the number of monte carlo simulations done for each leaf node
4. All 3
5. Something else

by **shedletsky** » 11 Sep 2016, 21:45

Actually found it in the Magarena docs.

It is the number of seconds the AI will spend thinking (when? for the whole turn? or for every choice that requires MCTS?)

I was curious where diminishing returns set in. Has anyone built a chart of the strength of the 8 different levels? I saw the one in the Magarena wiki but only for levels 4 and 8.

by **melvin** » 12 Sep 2016, 01:53

Hi shedletsky, it is per choice. I don't think anyone has done the full chart as it takes quite a while to play each game at 8s per choice.

by **shedletsky** » 12 Sep 2016, 07:28

How many sims does MCTS do in 8 seconds, typically?

What is the bottleneck?

by **melvin** » 12 Sep 2016, 09:49

shedletsky wrote:How many sims does MCTS do in 8 seconds, typically?

It depends on the number of cores, state of the game (beginning or near the end), and type of deck (affects number of moves till end game). You can see numbers for your machine in logs/game.log, there should be lines that look like

Code: Select all: MCTS cheat=false index=1 life=20 turn=1 phase=FirstMain sims=589 time=6027

The number of sims is indicated on that line. On my quad core machine, I get about 600 sims for 6s worth of thinking time at the beginning of the game. As each simulation runs till the game is over, when the game is near the end the number of simulations will be more.

shedletsky wrote:What is the bottleneck?

One of them is the time taken to generate the options for each choice. Some choices potentially could have a lot of different options, such as discarding a large hand at end of turn.