Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Question about Lazy eval

Author: Robert Hyatt

Date: 10:45:44 10/05/99

Go up one level in this thread


On October 05, 1999 at 12:28:46, Bruce Moreland wrote:

>
>On October 05, 1999 at 05:25:21, Bas Hamstra wrote:
>
>>What are good ways to cut down the number of evals? I saw Bob Hyatt post that he
>>could easily double NPS when using "Lazy Eval".
>>
>>What is a correct way to do that? Is there more to it than the qsearch "delta"
>>type of pruning?
>
>He couldn't double NPS, that's crazy.
>
>bruce


No... and I didn't read what he wrote there carefully when I responded to
it.  I generally do a full, slow eval on about 10% of the positions I search,
which means that the lazy eval cuts out about 90% of the time before doing the
whole thing..  and even so, my eval is taking 40-50% of the total search time
when profiled.  I don't know what turning lazy eval off will do, but here is a
quick run:

kopec22 depth=11  23.19 secs with lazy eval     nps=172K
                  32.15 secs without lazy eval  nps=123K

kopec3  depth=11  106 secs   with lazy eval     nps=152K
                  135 secs   without lazy eval  nps=119K

So it seems to be worth something around 50%...  ie I go 50% slower without
it than I do with...

on two test positions, of course...



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.