Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Programmers Question: Hashing and Alpha/Beta bounds

Author: Volker Böhm

Date: 10:31:54 06/06/05

Go up one level in this thread


Hello Johannes,


1. A value <= Alpha is stored as an upperbound
2. A value >= Beta is stored as an lowerbound
3. A value > Alpha & < Beta is stored as exact

retreiving the value from hash:

if exact return value
if upperbound beta = min(beta, value)
else if lowerbound alpha = max(alpha, value)

if alpha >= beta return value;

Thus if ever the window between alpha and beta <= 0 you can terminate the search
this is not unsound.

Greetings Volker



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.