Search found 200 matches

by Harald
Mon Jul 26, 2021 8:50 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Static exchange evaluation with promotion
Replies: 23
Views: 3537

Re: Static exchange evaluation with promotion

The sequence is like that, if the white rook move (Rc8) is the move in question: Rc8 (+500) Bc8 (-500) Pc8 (+300 + 900 - 100) = 1100 when the material values are like 900,500,300,300,100 / Q,R,B,N,P In this case the value is: Rc8 (+500) = 500 because in ... Bc8 (-500) Pc8 (+300 + 900 - 100) = 1100 ...
by Harald
Wed Jul 21, 2021 9:48 pm
Forum: Computer Chess Club: General Topics
Topic: Following Principal Variations in PVS
Replies: 2
Views: 922

Re: Following Principal Variations in PVS

Your algorithm does not work since a move anywhere in the search tree can be the same move as in pv_table[0][N]. You would rate too many moves too high, not just the PV. The PV moves moveM to moveN are only valid if the moves move0 to moveM-1 are in the PV. The PV is the best variation known so far ...
by Harald
Wed Jun 23, 2021 9:38 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Game Phase and tapered PSQT evaluation
Replies: 15
Views: 3920

Re: Game Phase and tapered PSQT evaluation

I am in the mood to explain it. int gamephaseInc[12] = {0,0,1,1,1,1,2,2,4,4,0,0}; is just a weight table of midgame/endgame weights for each piece P,p,N,n,B,b,R,r,Q,q,K,k. Note the sum of these weights for all 32 opening position pieces is 24. This is not the piece score in the midgame/endgame but a...
by Harald
Sat Apr 24, 2021 6:52 pm
Forum: Computer Chess Club: General Topics
Topic: Playing with "The Secret of Chess"
Replies: 11
Views: 4954

Re: Playing with "The Secret of Chess"

When I last wrote about this topic (in February I think) I started with my own version of texel tuning. That is tuning the evaluation function with a large set of EPD/FEN positions together with the game outcome (0, 1/2, 1). The tuning is just incrementing or decrementing one parameter at a time and...
by Harald
Tue Feb 16, 2021 2:49 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Coding Adventure: Chess AI
Replies: 21
Views: 3836

Coding Adventure: Chess AI

I just found this video from Sebastian Lague (Feb 12, 2021):
Coding Adventure: Chess AI
https://www.youtube.com/watch?v=U4ogK0MIzqk

Chess programming looks so easy! :-)
by Harald
Thu Feb 04, 2021 5:03 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Sorting moves during move ordering
Replies: 16
Views: 4489

Re: Sorting moves during move ordering

What about quicksorting only the left half of the move array recursively? function quicksort(array) if length(array) > 1 pivot := select any element of array left := first index of array right := last index of array while left ≤ right while array[left] < pivot left := left + 1 while array[right] > p...
by Harald
Wed Feb 03, 2021 5:30 pm
Forum: Computer Chess Club: General Topics
Topic: Playing with "The Secret of Chess"
Replies: 11
Views: 4954

Re: Playing with "The Secret of Chess"

Copyright issue? The book has a copyright notice. And I took all features and all numbers from the book. On the other hand this is a C++ program and not a text. That is much more than a translation. Ideas and algorithms in software are free anyway (or should be). Most of the features are well known ...
by Harald
Wed Feb 03, 2021 12:45 pm
Forum: Computer Chess Club: General Topics
Topic: So what do we miss in the traditional evaluation?
Replies: 29
Views: 8672

Re: So what do we miss in the traditional evaluation?

To me, this is a very interesting approach. It's essentially mentor-assisted evaluation function optimization (see https://elidavid.com/pubs/mentor.pdf). I imagine I'd do it by implementing every eval term known to man (taking them, for example, from L. Tsvetkov's compendium). Once you calculate al...
by Harald
Sat Jan 30, 2021 4:01 pm
Forum: Computer Chess Club: General Topics
Topic: So what do we miss in the traditional evaluation?
Replies: 29
Views: 8672

Re: So what do we miss in the traditional evaluation?

Please have a look at another thread:
Playing with "The Secret of Chess"
viewtopic.php?f=2&t=76453
by Harald
Sat Jan 30, 2021 3:56 pm
Forum: Computer Chess Club: General Topics
Topic: Playing with "The Secret of Chess"
Replies: 11
Views: 4954

Re: Playing with "The Secret of Chess"

... EvalTopicPieceActivity , Bishop attacking opp defended pawn, B, 205322, -10, 0, 0, -146849, 0, 948, 265 EvalTopicPieceActivity , Bishop xray attacking center, B, 11910, 4, 8, 7, 85999, 0, 948, 213 EvalTopicPieceActivity , Bishop xray attacking square in front of opp backward pawn, B, 1520, 6, 6,...