Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: shredder 8 and weird PVs? (sandro?)

Author: Tord Romstad

Date: 09:28:39 01/19/04

Go up one level in this thread


On January 19, 2004 at 12:16:47, Daniel Clausen wrote:

>On January 19, 2004 at 11:43:21, Sune Fischer wrote:
>
>[snip]
>
>>IMO the PV is a non-essential feature, having to do it "correctly" messes
>>up the code and slows down the engine.
>
>The few lines (like Bruce suggests on his site) mess up the code? I don't see
>how.. it's seems to be very clear and straightforward to me. Not sure about the
>speed at the moment, but I'd be surprised if it's that much. IMHO,
>xboard-related code or checks whether someone tapped something on the keyboard
>in the middle of search() mess up the code a bit more. :)

Sune does all such stuff in a separate thread.  :-)

I agree that the difference in speed probably isn't noticable (at least
not in a very slow engine like mine), but Like Sune, I think it feels
cleaner to view building a PV as a task separate from the search.  I
originally changed my code to extract the PV from the hash table because
this was the easiest option when I implemented MTD(f), but after getting
used to it I like it so much that I would probably keep it like this
even if I changed back to PVS.

>
>>That's just more than I want to spend on a fun-to-have feature.
>
>I can understand this POV, but if I'd buy a commercial product and want to use
>it for analyzing, I wouldn't be too happy if the PV is useless (except for the
>1st move)

I haven't seen the PVs Shredder produce, but in my own engine it seems
that the problem with wrong PVs is very rare.  The first two moves always
seem to be correct, and I can only remember a handful of cases where there
was something obviously wrong later in the PV.  I'm sure it happens a
lot more frequently than I notice it, though.  Of course I don't study
all the thousands of PVs my engine prints.

Tord



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.