Author: chandler yergin
Date: 18:32:54 10/11/05
Go up one level in this thread
On October 11, 2005 at 21:17:18, Michael Yee wrote: >On October 11, 2005 at 20:47:54, chandler yergin wrote: > >>On October 11, 2005 at 20:34:28, Michael Yee wrote: >> >>>On October 11, 2005 at 19:52:46, chandler yergin wrote: >>> >>>>On October 11, 2005 at 19:43:59, Michael Yee wrote: >>>> >>>>>On October 11, 2005 at 17:46:02, chandler yergin wrote: >>>>> >>>>>>I apologize if I have offended anyone. >>>>>>A case of "Apples & Oranges" again.. >>>>>>Misunderstandings.. >>>>>>Stephen, and a few others here, know I seldom voice "Opinions"; >>>>>>I Post facts.. >>>>>>That way... if someone differs from the Post, they should attack the Fact, >>>>>>not the Poster. >>>>>>It doesn't always work that way... >>>>>>Everything I have Posted about Computer Chess Programs..I gave the Link >>>>>>Everything else I have Posted about Engines, Analysis Modules, is directly >>>>>>from the Chessbase Manual. It therefore refers to the Top Commercial >>>>>>Programs only.. Fritz, & Shredder >>>>>>Many of you that Program your own Engines 'tweak' them as you desire, >>>>>>and have a lot of fun. >>>>>>Players mostly use the Top Commercial Programs to assist in their play >>>>>>and improve their expertise. >>>>>>Thanks to a recent Post by Dan H. some of the confusion has been cleared up. >>>>>>Chessbase does use Mini/Max and so does indeed search every legal move >>>>>>for every position. >>>>>>So the "Apples & Oranges" now are just the difference between the Top >>>>>>Commercial Programs and the others. >>>>>>I find it very intersting that some of the 'lesser' Engines are really >>>>>>kicking Butt! Congrats to all! Keep it up... >>>>>>A Swift Kick only hurts for a little while.. >>>>>>;) >>>>>>Chan >>>>> >>>>> >>>>>The posts from Dan don't say that chessbase uses minimax and searches every >>>>>legal move for every position. >>>> >>>>I know he didn't say it.. I said it! >>>> >>>> In fact, he said something almost the >>>>>opposite--that if a program worked that way, it would be crushed. >>>> >>>>Just plain wrong..sorry. >>>>> >>>>>You actually supplied evidence of the answer in one of your other posts (where >>>>>you provide a description of the analysis output). The analysis window reported: >>>>> >>>>>search depth = 12 (selective depth 40) >>>>>positions searched = 4.2 x 10^7 >>>> >>>>I was using an example.. the type of info the Analysis Module window shows. >>>> >>>>> >>>>>If the analysis module really searched every position up to depth 12 >>>>>(approximately 20 moves, 20 replies to each of those moves, 20 replies to each >>>>>of those replies, etc.), then it would have searched >>>>> >>>>>20^12 = 4.1 x 10^15 positions >>>>> >>>>>This is way more than what was reported in the analysis window. (And the 20 is a >>>>>very low estimate of average moves per position anyway.) Instead, >>>>> >>>>>4.32^12 = 4.22 x 10^7 >>>>> >>>>>shows a branching factor that's more like 4--i.e., the program was not searching >>>>>every move in every position. >>>>> >>>>>Michael >>>> Michael, Please read the Chessbase Manual! >>>>Do you have Chessbase? Do you have Fritz or Shredder? >>>>If so Start the engine look at the Analysis Window as I have requested. >>>>You will find what I said. EVERY Legal move in the position is evaluated. >>>>It's the way it works. Like it or not. >>> >>>Some commercial engines I have include an old fritz 7, shredder 9 uci, fruit >>>2.2, and gandalf 6. I've analyzed positions before (e.g., during some of the >>>recent World Championship games from Argentina). What I see are depths, >>>selective depths, and node counts that are not consistent with a program that >>>searches every legal move in every position. >>> >>>You're right that engines do look at each move in the root (initial) position >>>(as Dann noted in another post). If that's what you meant, then I agree. But you >>>seem to referring to *all* positions (not just the root). >> >>No Michael, and as Shakespeare said.. "Aye, there lies the rub.." >>Please re-read my Post carefully. >>Well.. here.. >>"Start your Engine for a position or at any part of a game. >>Look at the analysis window >>What do you see? >>The analysis module should show the following: >>The name of the Engine >>The search depth (brute force selective) Example "12/40" means that all >>variations were >>searched to a depth of 12 ply, while some promising continuations were checked >>down to 40 ply. >>Next should show the move currently being investigated. Example f4-d6 (3/47) >>meaning number 3 of 47 legal moves in the position. >>Next it will show the speed at which the program is running. >>Example: 403kN/s means it is looking at 403,000 nodes (= positions) per second. >>This is normal on a 400MHz processor. >>The main variation for example shows "=(0.00)", then the best sequence of moves >>the program has found so far, the amount of time it has spent computing on the >>position,(1 min. 46 sec) and the number of positions it has examined >>(41937kN =41,973,000) >>The evaluation expressed in units of a pawn, always from the point of view of >>White >>"+0.53) means the program thinks White has an advantage of about half a pawn; >>" (-3.52" indicates Black is more than a piece up. If Mate is found the Program >>stops calculating and displays the Mate. (Mate in 6)." >> >>What if anything is incorrect in the above? > >Nothing's wrong with what's posted above. > >But you've asserted in other places that top chessbase engines "search every >legal move for every position". > >http://www.talkchess.com/forums/1/message.html?455204 They do Michael A point to remember.. the Top Programs support large Databases. Chessbase Mega99.cbh for example consists of 1161937 Games 54,277 Opening Keys 54,277 Positions. In order to properly "Classify" a Position per ECO it must search every possible legal move in a position. That's what we pay em for. > >Yet the above numbers in the above (depth=12 and nodes=42,000,000) don't support >that point of view. I'm sure it does.. > >>> >>>You yourself computed a while ago an estimate of the number of move sequences >>>that can happen from the start position. Given the nodes per second you see in >>>the analysis windows, how could the engine possibly be following all move >>>sequences (even taking into account transpositions)? >> >>That was Dann, not me.. > >I might be remembering wrong, but I thought it was in the context of trying to >estimate the number of possible games as part of an argument that there weren't >even that many atoms in the universe and so chess could never be solved. (But >believe me--I certainly don't want to revive that old debate again!) Bruce Posted why.. the Link I gave also shows why.. > >Michael
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