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        Arimaa >> Bot Development >> Bots thinking in your time
        
(Message started by: Swynndla on Apr 14^th, 2006, 5:51pm)

Title: Bots thinking in your time
Post by Swynndla on Apr 14^th, 2006, 5:51pm

Which bots look ahead when it's not there turn to move? They *do* do this right? ... for a CC bot that typically looks ahead say 2 ply, then looking ahead when it's your move would mean it could gain a ply ... right??

Title: Re: Bots thinking in your time
Post by BlackKnight on Apr 14^th, 2006, 8:21pm

Because of the exponential growth of the search tree 2 minutes are usually not enough to gain another ply. But I guess 1 or even 2 steps might be possible depending on the position.

For example:
Depth Time Elapsed
---------------------------
2 0.0
3 0.0
4 0.0
5 0.0
6 0.0
7 0.0
8 3.0
9 8.0
10 18.0
11 42.0

But this doesn't say anything yet about how to make the best use of this time. I was thinking of either just assuming it's my turn again to find already a good variant, or considering also the opponents move, and then continuing the calculations in my turn. But Loc doesn't make use of those ideas.

But I think Toby has found a very interesting way of managing the time, so that Gnobby sometimes looks ahead quite a lot and thinks for a long time, and after that makes moves quite quickly.

Title: Re: Bots thinking in your time
Post by IdahoEv on Apr 14^th, 2006, 11:52pm

on 04/14/06 at 20:21:17, BlackKnight wrote:

But I think Toby has found a very interesting way of managing the time, so that Gnobby sometimes looks ahead quite a lot and thinks for a long time, and after that makes moves quite quickly.

I am certain you are right. I am stuck on GnoBot2005_Fast on the bot ladder. I think Gnobby is one of the very few bots that really does play much better at _Fast than at 2Ply. Quite consistenly, Gnobby_fast will burn most of its reserve time around turns 5 - 7, just after the opening, up to 4 minutes on a single move.

Just based on its' moves after that large use of reserve time, I'm pretty convinced that is is spending that time to search 3 or 4 ply ahead; the moves are consistently deeper and more clever than what I'm used to bots making. (And of course, GnoBot P2 isn't allowed to do that).

It's quite clever, Toby gets props for it.

I'd like to know - does it decide to burn all that time just based on the current board at the time, or does it just assume that turns 5-7 are likely to be critical turns?

Title: Re: Bots thinking in your time
Post by 99of9 on Apr 15^th, 2006, 12:49am

As Blackknight's table indicates, Gnobby's extra thinking time does not allow it to go much deeper. Maybe one or two steps on that one turn.

The decision to use extra time is simply based on how much time is in reserve, and how long the search has taken so far. So it's really not that clever! But I'm glad you like how it plays.

Title: Re: Bots thinking in your time
Post by Fritzlein on Apr 15^th, 2006, 9:59am

99of9, I think Gnobot's time management is pretty good, but it is weird to burn the whole reserve when the reserve is eight or ten times the increment. A tiny refinement (useful mostly in fast and blitz games) might be

not

"try to complete another step if you think you can within the reserve time"

but rather

"try to complete another step if you think you can within the reserve time or four times the increment, whichever is less"

That way Gnobot won't blow all of a hard-won reserve in a single move.

Title: Re: Bots thinking in your time
Post by 99of9 on Apr 15^th, 2006, 5:59pm

That is a good suggestion. I will probably try it out when I implement these fancy new time controls.