Computer Chess Club Archives


Search

Terms

Messages

Subject: Rehashing (was Re: Hash replacement question)

Author: Stuart Cracraft

Date: 07:27:28 01/15/98

Go up one level in this thread


The research I've read indicates that a two-tiered
structure with nodes-based-replacement for the one
slot that most people check for subtree height is
preferred.

That is, the number of nodes that were searched
for this subtree must be greater than the number of
nodes recorded for the position already in the hash
table.

Recently, I replaced my single-tier depth-based
replacement with single-tier nodes-based and
experienced a small improvement.

Later I will go to a two-tier algorithm so that new
things always get stored.

Also, I think we need to discuss rehashing. Does somenoe
have this implemented? It seems like rehashing for say
8 slots based on nodes-recorded would be better than
single-tier since quite a few collisions could be handled
without replacing information already at that slot.

Does anyone have some good algorithms for this? Let's say
I hash to index X and find it is filled. What is a good
algorithm to choose another index to try? And it seems like
that algorithm would have to be deterministic because the
next time into this entry, I'd want to go search those
alternate indexes/slots in the same order to find where I'd
stored it.

--Stuart



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.