Search found 12 matches

by omnivorist
Sun Jan 19, 2020 8:33 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Exploring an unusual evaluation function
Replies: 19
Views: 2900

Re: Exploring an unusual evaluation function

Many years ago some work was done on basing piece values on mobility. In particular Reinhard Scharnagl (passed away in 2015) used this approach with his engine SMIRF. Information is not easy to find these days, but the Wayback machine has quite a bit: https://web.archive.org/web/20060507091953/http...
by omnivorist
Sun Jan 19, 2020 12:28 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Exploring an unusual evaluation function
Replies: 19
Views: 2900

Re: Exploring an unusual evaluation function

Due to your initial thanks in Advance (Adv<thanks>ance), I wrongly assumed you are this David Wilson , author of Advance and Delta - starting a comeback after a long break from chess programming ;-) Sorry but no. I’m a newcomer to the field unaware of both my namesake and his work. I am retired the...
by omnivorist
Sun Jan 19, 2020 12:12 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Exploring an unusual evaluation function
Replies: 19
Views: 2900

Re: Exploring an unusual evaluation function

I hope my musings might inspire others to look for a 'sweet spot' in the eval/search balance. You are right, my thinking and aesthetic preference is kind of the opposite to yours on this one. My thinking was more like: Why do you have to search when the information is already all there in a condens...
by omnivorist
Sat Jan 18, 2020 9:40 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Exploring an unusual evaluation function
Replies: 19
Views: 2900

Re: Exploring an unusual evaluation function

Gerd Isenberg has pointed out that my idea is by no means a new one,
I’m grateful for that. It might save a lot of time.
All the same. Writing my engine has wetted my appetite for chess programming,
by omnivorist
Fri Jan 17, 2020 10:47 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Exploring an unusual evaluation function
Replies: 19
Views: 2900

Re: Exploring an unusual evaluation function

omnivorist wrote:
Fri Jan 17, 2020 10:41 pm
Gerd Isenberg wrote:
Fri Jan 17, 2020 3:10 pm

It would be great to research the early history of chess engines. Are you aware of any sources of information ?
Hi Gerd, I replied before looking at the links you provided. I will look at these and explore the CPW site. It looks like it might be the answer to my question.
by omnivorist
Fri Jan 17, 2020 10:41 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Exploring an unusual evaluation function
Replies: 19
Views: 2900

Re: Exploring an unusual evaluation function

Hi Dave, may be you are aware that early programs like Barricelli's Freedom and Marsland's Wita used mobility aka ratio of computer's moves / opponent moves as evaluation term, and Papa the logarithm of that product to form an entropy. I wasn’t aware of that Gerd. Thanks so much for your post - rea...
by omnivorist
Fri Jan 17, 2020 11:30 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Exploring an unusual evaluation function
Replies: 19
Views: 2900

Re: Exploring an unusual evaluation function

Even so, I think the idea of ‘going back’ to some form of simple abstract metric of positional strength is a project worth pursuing. Can you give reason for that? I think a linear increase in compute for the eval is more promising than an exponential inc. in comp. for the search. I have to say my r...
by omnivorist
Thu Jan 16, 2020 6:51 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Exploring an unusual evaluation function
Replies: 19
Views: 2900

Re: Exploring an unusual evaluation function

How one’s dreams can come crashing down. When I first began to think about this project I thought the evaluation function would be so fast that I’d be able to explore a whole bunch more levels of the search tree and consequently uncover the long-range results of maximising mobility. No such luck. Bu...
by omnivorist
Thu Jan 16, 2020 6:39 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Exploring an unusual evaluation function
Replies: 19
Views: 2900

Re: Exploring an unusual evaluation function

Yes, computing legal moves purely for eval is almost as costly as a whole extra level of search depth. The code comes for free but not the compute !
I naively thought, when I started out, that the compute would be free also.
by omnivorist
Thu Jan 16, 2020 6:13 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Exploring an unusual evaluation function
Replies: 19
Views: 2900

Re: Exploring an unusual evaluation function

Yes YUFe - in my first implementation, knights were being given away cheap on account of maximum 8 moves, compared with the bishop’s 14. I attempted to get over this by assigning a weighting to each piece type and consequently biasing it to value knights more highly. It does appear to make a signifi...