Database snapshot

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Master Om
Posts: 335
Joined: Wed Nov 24, 2010 9:57 am
Location: INDIA

Re: Database snapshot

Post by Master Om » Fri Oct 25, 2019 3:09 am

Ovyron wrote:
Fri Oct 25, 2019 1:31 am
Master Om wrote:
Thu Oct 24, 2019 4:35 pm
2ndly The analysis is based on lines i choose to play with all possible opponent replies and mine.
"All possible opponent replies" is the culprit here, because 90% of those moves will not be played, and if they're played you're already in good shape because the opponent missed (say) the top 4 moves and played a bad one. If you only analyze the top 4 and your opponent plays a different move, and it turns out it was better than those, then it's a problem with the method itself because you should have had that move in your top 4 in the first place.

Now I'm going to reveal something, I've always given funny names to my analysis methods, such as "Carousel" or "Power Drifting" and such. Most of them were garbage, but I didn't know until someone defeated them. One of those methods was "The Kitchen Sink", some of my opponents might recognize that one. Well, the kitchen sink was nothing but drawing an analysis tree like a pyramid, checking every root node for me and my opponent at the root, and ending with a tree that looks upside down, similar to what you're doing.

When I lost using it I discovered that I could have saved the game if I didn't waste so much time analyzing so many irrelevant lines. The key to analysis is to find what is the best opponent's move, and refute that. That's the only move you need to check. You check the others to make sure it's not one of them, but if you have to analyze more than 3 alternatives to make sure opponent's best isn't missed, your method to rank the top 4 moves on a position is flawed, and fixing it would make you save a lot of time, because on a position with 20 playable moves, you only need to check 4 lines and discard the other 16. 80% of time saved.
methodology of play varies person to person. May be culprit but not for me. Most of time i choose what to play and not by a program in the initial stage. hence to document the variations analysis will be done once. I dont have to do analysis now. All my opening database has been ready with respect to specific openings.
if I didn't waste so much time analyzing so many irrelevant lines.
Stars dont shine without darkness. Nothing is irrelevant.

Also heavy analysis is needed when u have a 0.00 position with more than 7 8 moves with same score. Otherwise plan is always evident what to play and doesnot need further analysis . Those type are one time process for few moves unless your opponent diverts. If u miss u lose If he misses u win.
Always Expect the Unexpected

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Ovyron
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Joined: Tue Jul 03, 2007 2:30 am

Re: Database snapshot

Post by Ovyron » Fri Oct 25, 2019 9:03 am

Master Om wrote:
Fri Oct 25, 2019 3:09 am
hence to document the variations analysis will be done once. I dont have to do analysis now. All my opening database has been ready with respect to specific openings.
That is really weird, in my experience I've been having to check and recheck lines that I have already checked ad nauseam because the analysis becomes obsolete.

A few days ago my main line as black for the Sicilian defense just died, and I had to go back and check every single move by black yet again, and the analysis of the alternatives was so old that there was a lot of moves ranked incorrectly, and at the end the Najdorf looked worse than the alternatives :shock:

I'd not have needed to do that if I believed my analysis of the Sicilian was in stone and definitive, and it was tempting to create a new thread titled "Has the Najdorf been busted??", but I'm still investigating the other alternatives to see if the same happens to them and it's just that 1...c5 is some 0.02 worse than 1...e5 and the entire Sicilian would be busted.

One year ago I could have agreed with you, but with things like this or the Italian being better for black I think we're in the middle of an opening revolution and it's possible one day it hits you and you have to revise what you thought was definitive in your opening database.

Uri Blass
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Re: Database snapshot

Post by Uri Blass » Fri Oct 25, 2019 9:37 am

I think that we need first 100% reliable engine for analysis otherwise we can be sure of nothing.
Stockfish is not reliable and it can give mate score for position that is a draw by the 50 move rule.

We need an engine that if it say mate it is really a mate and it check carefully that it is not a draw by the 50 move rule.

We need an engine that put all the position in the hash tables and not some key that may be the same for different positions.
It may be interesting to know how many tablebases position get wrong mate score by stockfish because stockfish does not memorize the full position in the hash and the key may be the same for different positions so it may get the conclusion that position A has mate score only because position B has mate score when practcially position A has a draw score or even worse.

I never saw an example when it happens not because of the 50 move rule but I would like people to test stockfish automatically and have a loop of searching all the 7 piece tablebases positions without tablebases to find out if it get wrong mate in 1 out of million positions or maybe more than it or less than it.

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Ovyron
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Re: Database snapshot

Post by Ovyron » Fri Oct 25, 2019 12:50 pm

I think such an engine would manage to draw all its games even if it couldn't win as much as Stockfish. Reliable would mean it could identify losing moves and avoid them.

I've been fearing the existence of such an engine for years, if it was created it'd mean the end of correspondence games and decided games and if it is coming I'm basically living the last years of the sport.

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Master Om
Posts: 335
Joined: Wed Nov 24, 2010 9:57 am
Location: INDIA

Re: Database snapshot

Post by Master Om » Fri Oct 25, 2019 6:51 pm

Ovyron wrote:
Fri Oct 25, 2019 9:03 am
Master Om wrote:
Fri Oct 25, 2019 3:09 am
hence to document the variations analysis will be done once. I dont have to do analysis now. All my opening database has been ready with respect to specific openings.
That is really weird, in my experience I've been having to check and recheck lines that I have already checked ad nauseam because the analysis becomes obsolete.

A few days ago my main line as black for the Sicilian defense just died, and I had to go back and check every single move by black yet again, and the analysis of the alternatives was so old that there was a lot of moves ranked incorrectly, and at the end the Najdorf looked worse than the alternatives :shock:

I'd not have needed to do that if I believed my analysis of the Sicilian was in stone and definitive, and it was tempting to create a new thread titled "Has the Najdorf been busted??", but I'm still investigating the other alternatives to see if the same happens to them and it's just that 1...c5 is some 0.02 worse than 1...e5 and the entire Sicilian would be busted.

One year ago I could have agreed with you, but with things like this or the Italian being better for black I think we're in the middle of an opening revolution and it's possible one day it hits you and you have to revise what you thought was definitive in your opening database.
I dont play same variations always as i experiment a lot. For that I prepare my variations long before hand.
I experiment a lot and lose a lot :D

Opening idea changes because engine eval changes. When a new engine comes it changes many evaluations of many crucial openings. Since there is no perfect engine we have to check it. But Ideas remain same. Thats why human knowledge is far superior in chess IMHO.

I Play what i like sometimes and for me all lines are playable.
Always Expect the Unexpected

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