Search found 3244 matches

by Sven
Tue Jun 18, 2019 7:55 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: strange code for tt
Replies: 3
Views: 264

Re: strange code for tt

if alpha > start_alpha (which is the alpha at the start of search()), then the best_score can never be <= start_alpha. That depends on your type of alpha-beta search. With "fail hard" you are right but with "fail soft" best_score is initialized to -INF and can certainly be below your current window...
by Sven
Sun Jun 16, 2019 4:24 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Explanation of the Cute Chess message 'connection stalls'
Replies: 15
Views: 416

Re: Explanation of the Cute Chess message 'connection stalls'

For iterative deepening, I understand what it is but I have to figure how to do it. For now, I use a recursive function. Iterative deepening is a concept one level above the tree search itself. The latter can be implemented recursively or iteratively. int search(Board b, int d, int alpha, int beta,...
by Sven
Sun Jun 16, 2019 12:47 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Explanation of the Cute Chess message 'connection stalls'
Replies: 15
Views: 416

Re: Explanation of the Cute Chess message 'connection stalls'

but in the current state of the program there is no provisional best move, to be returned when the 'stop' command is received. I have to think how I will make that. The typical solution for this problem in classical chess engines is iterative deepening: the engine performs a search to depth 1, 2, 3...
by Sven
Mon Jun 10, 2019 12:56 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: The Poor Man's KP Bitbase
Replies: 5
Views: 450

Re: The Poor Man's KP Bitbase

Notice that for the first two possibilities, the position of the strong king is irrelevant. The draw only depends on the position of the weak black king. We can almost solve the entire KPK ending without knowing the position of the white king! For example, in the following position the white king c...
by Sven
Sun Jun 09, 2019 9:09 am
Forum: Computer Chess Club: General Topics
Topic: Draw or Black win?
Replies: 12
Views: 325

Re: Draw or Black win?

Graham Banks wrote:
Sun Jun 09, 2019 7:50 am
I have one engine that thinks it's a dead draw and another that thinks Black is winning.
Which engine thinks it's a dead draw? POS? :lol:

I tested with SF and Jumbo, both say Black is clearly winning.
by Sven
Sat Jun 08, 2019 10:17 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Hash collision?
Replies: 42
Views: 1464

Re: Hash collision?

3. Size of hash table, 2097152, with 4 buckets [...] 5. Using the bottom 20 bits of this to calculate the index 6. Using the top 16 bits to store in the table I'm not sure, does this mean I have an effective hash length of 21 + 16 - 4, so 33 bits? In my view you have 2^21 hash entries, 2^2 entries ...
by Sven
Sun Jun 02, 2019 8:01 am
Forum: Computer Chess Club: General Topics
Topic: New Jumbo release 0.6.107
Replies: 2
Views: 226

Re: New Jumbo release 0.6.107

It is not about "luck". I do not get a native IPv4 address from my provider, therefore I know it won't work.
by Sven
Thu May 23, 2019 9:31 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: On-line engine blitz tourney May
Replies: 11
Views: 1353

Re: On-line engine blitz tourney May

Start using git, that will offer you a new target for ranting :D
by Sven
Sun May 12, 2019 12:10 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: A bug is squashing me. HELP!
Replies: 20
Views: 1557

Re: A bug is squashing me. HELP!

So far all I have is a material searcher. From the initial position it returns a score of either 100 or -100 depending upon the modification or search depth. Never any other value. I update material on the fly in make and unmake. When a search is done the board and all starting data is the same as ...