[computer-go] Re: static evaluators for tree search

2009-02-17 Thread Dave Dyer
While your goal is laudable, I'm afraid there is no such thing as a simple tree search with a plug-in evaluator for Go. The problem is that the move generator has to be very disciplined, and the evaluator typically requires elaborate and expensive to maintain data structures. It all tends to be

Re: [computer-go] Re: static evaluators for tree search

2009-02-17 Thread George Dahl
I am aware such a decoupled program might not exist, but I don't see why one can't be created. When you say the move generator has to be very disciplined what do you mean? Do you mean that the evaluator might be used during move ordering somehow and that generating the nodes to expand is tightly

[computer-go] Re: static evaluators for tree search

2009-02-17 Thread Dave Dyer
Do you mean that the evaluator might be used during move ordering somehow and that generating the nodes to expand is tightly coupled with the static evaluator? That's the general idea. No search program can afford to use a fan-out factor of 361. The information about what to cut has to come

[computer-go] Re: static evaluators for tree search

2009-02-17 Thread Dave Dyer
Do you mean that the evaluator might be used during move ordering somehow and that generating the nodes to expand is tightly coupled with the static evaluator? That's the general idea. No search program can afford to use a fan-out factor of 361. The information about what to cut has to come

[computer-go] Re: static evaluators for tree search

2009-02-17 Thread Dave Dyer
This is old and incomplete, but still is a starting point you might find useful http://www.andromeda.com/people/ddyer/go/global-eval.html General observations (from a weak player's point of view): Go is played on a knife edge between life and death. The only evaluator that matters is is

Re: [computer-go] Re: static evaluators for tree search

2009-02-17 Thread George Dahl
I really don't like the idea of ranking moves and scoring based on the distance to the top of a list for a pro move. This is worthless if we ever want to surpass humans (although this isn't a concern now, it is in principle) and we have no reason to believe a move isn't strong just because a pro

Re: [computer-go] Re: static evaluators for tree search

2009-02-17 Thread Michael Williams
George Dahl wrote: I guess the another question is, what would you need to see a static evaluator do to be so convinced it was useful that you then built a bot around it? Would it need to win games all by itself with one ply lookahead? Here is one way to look at it: Since a search tends to

Re: [computer-go] Re: static evaluators for tree search

2009-02-17 Thread Michael Williams
Michael Williams wrote: As for the source of applicable positions, that's a bit harder, IMO. My first thought was to use random positions since you don't want any bias, but that will probably result in the evaluation of the position being very near 0.5 much of the time. But I would still try

Re: [computer-go] Re: static evaluators for tree search

2009-02-17 Thread Gunnar Farnebäck
Dave Dyer wrote: If you look at GnuGo or some other available program, I'm pretty sure you'll find a line of code where the evaluator is called, and you could replace it, but you'll find it's connected to a pile of spaghetti. That would have to be some other available program. GNU Go doesn't

Re: [computer-go] Re: static evaluators for tree search

2009-02-17 Thread Jason House
On Feb 17, 2009, at 12:55 PM, Dave Dyer dd...@real-me.net wrote: While your goal is laudable, I'm afraid there is no such thing as a simple tree search with a plug-in evaluator for Go. The problem is that the move generator has to be very disciplined, and the evaluator typically requires

Re: [computer-go] Re: static evaluators for tree search

2009-02-17 Thread Darren Cook
I think it would be much more informative to compare evaluator A and evaluator B in the following way. Make a bot that searched to a fixed depth d before then calling a static evaluator (maybe this depth is 1 or 2 or something small). Try and determine the strength of a bot using A and a bot

Re: [computer-go] Re: static evaluators for tree search

2009-02-17 Thread George Dahl
Really? You think that doing 20-50 uniform random playouts and estimating the win probability, when used as a leaf node evaluator in tree search, will outperform anything else that uses same amount of time? I must not understand you. What do you mean by static evaluator? When I use the term, I

Re: [computer-go] Re: static evaluators for tree search

2009-02-17 Thread Darren Cook
Really? You think that doing 20-50 uniform random playouts and estimating the win probability, when used as a leaf node evaluator in tree search, will outperform anything else that uses same amount of time? Same amount of clock time for the whole game. E.g. if playing 20 random playouts to

Re: [computer-go] Re: static evaluators for tree search

2009-02-17 Thread Mark Boon
On Tue, Feb 17, 2009 at 8:35 PM, George Dahl george.d...@gmail.com wrote: Really? You think that doing 20-50 uniform random playouts and estimating the win probability, when used as a leaf node evaluator in tree search, will outperform anything else that uses same amount of time? You'll

RE: [computer-go] Re: static evaluators for tree search

2009-02-17 Thread David Fotland
: [computer-go] Re: static evaluators for tree search Really? You think that doing 20-50 uniform random playouts and estimating the win probability, when used as a leaf node evaluator in tree search, will outperform anything else that uses same amount of time? I must not understand you. What

RE: [computer-go] Re: static evaluators for tree search

2009-02-17 Thread David Fotland
Message- From: computer-go-boun...@computer-go.org [mailto:computer-go- boun...@computer-go.org] On Behalf Of Gunnar Farnebäck Sent: Tuesday, February 17, 2009 1:30 PM To: computer-go Subject: Re: [computer-go] Re: static evaluators for tree search Dave Dyer wrote: If you look at GnuGo

RE: [computer-go] Re: static evaluators for tree search

2009-02-17 Thread David Fotland
-boun...@computer-go.org [mailto:computer-go- boun...@computer-go.org] On Behalf Of George Dahl Sent: Tuesday, February 17, 2009 10:14 AM To: computer-go Subject: Re: [computer-go] Re: static evaluators for tree search I am aware such a decoupled program might not exist, but I don't see why one