Computer Chess Club Archives


Search

Terms

Messages

Subject: Mate in 80

Author: Alessandro Scotti

Date: 14:33:08 08/15/04


Today I was quite surprised to see my program proudly announcing a mate in 80,
especially considering that only a few days ago it missed a mate in one.
Anyway after a lot of debugging I *think* I have an idea about what's happening.
Suppose a position is stored as "mate in 5" in the hash table. If I transpose to
this position at depth=3 during the search, I have now a "mate in 8", which if I
transpose to at depth=7 becomes a "mate in 15" and so on...
I start to get in trouble if the position is very open and has a lot of
transpositions, in my case it was simply a KBB vs. K ending.
The most annoying effect is: mate scores don't mean a thing... even on the last
mate it returns a score of "mate in 12"!!!
I have checked against other programs and they don't seem to suffer from this
problem... am I doing something wrong? :-(




This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.