Search found 405 matches

by Chan Rasjid
Sat Jun 22, 2013 9:04 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: First post (and FailHigh question!)
Replies: 89
Views: 14964

Re: First post (and FailHigh question!)

Hello Patrice, You did mentioned earlier that your program has an old bug about wrong mate scores that you could not resolve - so you disabled mate score adjustment. You cannot do a half-measured hashing of mate scores. I suggest as a temporary measure, you do not store any +/- mate scores in your T...
by Chan Rasjid
Fri Jun 21, 2013 9:40 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: First post (and FailHigh question!)
Replies: 89
Views: 14964

Re: First post (and FailHigh question!)

Hello Thomas, Hi Chan, there is no bug and the engine did not see beyond its horizon. The Mate in 12 was found at general depth 18 but "selected depth" 24. So it extended certain lines up to depth 24 and to see there a Mate in 12 is expected. I know it is a Mate in 11 and the engine would probably h...
by Chan Rasjid
Fri Jun 21, 2013 9:29 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: First post (and FailHigh question!)
Replies: 89
Views: 14964

Re: First post (and FailHigh question!)

Hello Patrice, Hello, Don't know if it helps, but for me one part of the problem with wrong mate scores was in null moves pruning. In my condition to prevent zugzwang positions, I used the total number of non pawn pieces instead of the value for the current player. Now there are other variations wit...
by Chan Rasjid
Fri Jun 21, 2013 3:31 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: First post (and FailHigh question!)
Replies: 89
Views: 14964

Re: First post (and FailHigh question!)

Hello Sven, Of course they have to be different positions otherwise there could not be any "amplification". We could substitute 'OM' whenever we want to say 'amplification' if we like. :D The term "amplification" seems to be misplaced here. Those three positions refer to exactly the same mating sequ...
by Chan Rasjid
Fri Jun 21, 2013 10:32 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: First post (and FailHigh question!)
Replies: 89
Views: 14964

Re: First post (and FailHigh question!)

Hello Sven. This was what you wrote earlier : 4) The grandparent of A1, which is at ply=10, gets back "+(infi-17)", fails high, and stores "+(infi-7)" as lower bound in the TT, i.e. "mate in at most 7 plies from here". You said "stores" which means (infi - 7), an amplification, was hashed in the TT....
by Chan Rasjid
Fri Jun 21, 2013 5:08 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: First post (and FailHigh question!)
Replies: 89
Views: 14964

Re: First post (and FailHigh question!)

Hello Sven, Besides any misundertanding on our "disputes", only one of us is right; but it is not really important as we are not vying for the Nobel award! Or to head ICGA! We all learn otherwise how are we going to keep up with Robert Houdini who has the advantage of magic tricks! Through this thre...
by Chan Rasjid
Thu Jun 20, 2013 6:10 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: First post (and FailHigh question!)
Replies: 89
Views: 14964

Re: First post (and FailHigh question!)

Hello Thomas, I've read Bob's description in crafty how he does it (If I remember right it was storing the distance to the start of the current search). At the time I did not understand how this will work if 2 moves are actually played on the board, a new search starts and now older entries are retr...
by Chan Rasjid
Thu Jun 20, 2013 5:10 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: First post (and FailHigh question!)
Replies: 89
Views: 14964

Re: First post (and FailHigh question!)

Hello Sven, The unrestricted magnification of search mate scores happens and I think it is not a bug. I'm tired to repeat the same over and over again. If you like you may choose to reread what I wrote, or to ignore it. I think I explained well what can happen via transpositions and what can't. I ha...
by Chan Rasjid
Thu Jun 20, 2013 4:01 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: First post (and FailHigh question!)
Replies: 89
Views: 14964

Re: First post (and FailHigh question!)

I handle the Mate scores in my TT rather straight forward. I dedicate a few bits in the hash entry to store the ply the score comes from. And if the score is probed from a different ply and it is a Mate score the difference between the plys is added or subtracted. /*********************************...
by Chan Rasjid
Thu Jun 20, 2013 3:40 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: First post (and FailHigh question!)
Replies: 89
Views: 14964

Re: First post (and FailHigh question!)

Hello Thomas, So Natale's program behavior should not be a bug but rather is a case of search instability. The only difficulty is to explain when and why the mate score fail high stops as beta is progressively relaxed and researched at the root. But if this would be the case then it should show up i...