random evaluation perturbation factor
Moderators: hgm, Rebel, chrisw
-
- Posts: 2488
- Joined: Tue Aug 30, 2016 8:19 pm
- Full name: Rasmus Althoff
Re: random evaluation perturbation factor
In my CT800 project, this feature is called "eval blurring", and the available options are "off" or "+/-10/30/50 centipawns".
-
- Posts: 2250
- Joined: Wed Mar 08, 2006 8:47 pm
- Location: Hattingen, Germany
Re: random evaluation perturbation factor
Yep, they demonstrated that root random (choosing a root move randomly) loses badly versus leaf random (random eval) the higher the search depth >= 1. To avoid favouring the leaf random look ahead approach due to mate scores, root random also applied a look ahead with the same search depth, but all leaves evaluated zero. Repetition and 50 move rule were ignored in the experiments. I don't have the paper and game scores actually handy, but will soon post a cpw page on that topic.D Sceviour wrote:By the 'Beal effect' are you referring to "Random Evaluations in Chess", Don F. Beal and Michael C. Smith, ICCA Journal [17(1):3-9], March 1994? Is a text available for that publication?
-
- Posts: 106
- Joined: Mon May 12, 2014 10:08 am
- Location: Near Nijmegen
Re: random evaluation perturbation factor
The article is also published in "Advances in Computer Chess 7", H.J. van den Herik, I.S. Herschberg and J.W.H.M. Uiterwijk (1994).D Sceviour wrote:By the 'Beal effect' are you referring to "Random Evaluations in Chess", Don F. Beal and Michael C. Smith, ICCA Journal [17(1):3-9], March 1994? Is a text available for that publication?
Nothing is unstable (Lawrence Krauss)
-
- Posts: 2250
- Joined: Wed Mar 08, 2006 8:47 pm
- Location: Hattingen, Germany
Re: random evaluation perturbation factor
A paper available online which refers the Beal/Smith paper:D Sceviour wrote:By the 'Beal effect' are you referring to "Random Evaluations in Chess", Don F. Beal and Michael C. Smith, ICCA Journal [17(1):3-9], March 1994? Is a text available for that publication?
Mark Levene, Trevor Fenner (2001). The Effect of Mobility on Minimaxing of Game Trees with Random Leaf Values. Artificial Intelligence, Vol. 130, No. 1
https://pdfs.semanticscholar.org/eb82/0 ... 1e5a2d.pdf
-
- Posts: 2250
- Joined: Wed Mar 08, 2006 8:47 pm
- Location: Hattingen, Germany
Re: random evaluation perturbation factor
https://chessprogramming.wikispaces.com ... eaf+ValuesGerd Isenberg wrote:Yep, they demonstrated that root random (choosing a root move randomly) loses badly versus leaf random (random eval) the higher the search depth >= 1. To avoid favouring the leaf random look ahead approach due to mate scores, root random also applied a look ahead with the same search depth, but all leaves evaluated zero. Repetition and 50 move rule were ignored in the experiments. I don't have the paper and game scores actually handy, but will soon post a cpw page on that topic.D Sceviour wrote:By the 'Beal effect' are you referring to "Random Evaluations in Chess", Don F. Beal and Michael C. Smith, ICCA Journal [17(1):3-9], March 1994? Is a text available for that publication?
-
- Posts: 570
- Joined: Mon Jul 20, 2015 5:06 pm
Re: random evaluation perturbation factor
Thank you for posting the page. The links are very helpful.
-
- Posts: 464
- Joined: Sat Feb 28, 2015 4:37 pm
- Location: Argentina
Re: random evaluation perturbation factor
That random adition will be valid only for equal score positions or could even be enough to make a position with higher score than other with no randon having, with random, a lower score position than that other?
(Sorry for my Hollywood-Apache like english).
(Sorry for my Hollywood-Apache like english).