Any difference between analysis and engine play?

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Kohflote
Posts: 200
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Location: Singapore

Any difference between analysis and engine play?

Post by Kohflote » Tue Sep 02, 2008 12:26 am

Hi all,

Do pardon my ignorance. In a completed game, if I wanted to know the best move say on 25th move. What is the difference between
(a) if I use "analysis' mode to analyze 25th move and
(b) I let the engine to play at 25th move

both setting at say 18 plys?

Thank you!

Yours sincerely,
Kah Huat, Koh
- from Singapore

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Dr.Wael Deeb
Posts: 9635
Joined: Wed Mar 08, 2006 7:44 pm
Location: Amman,Jordan

Re: Any difference between analysis and engine play?

Post by Dr.Wael Deeb » Tue Sep 02, 2008 12:34 am

I personaly think that there is no difference at all for most of the engines....
_No one can hit as hard as life.But it ain’t about how hard you can hit.It’s about how hard you can get hit and keep moving forward.How much you can take and keep moving forward….

genorb

Re: Any difference between analysis and engine play?

Post by genorb » Tue Sep 02, 2008 2:59 pm

As Dr.Wael Deeb said, for most engine there is no different. But for Rybka 3 there is a small difference because the contempt factor is not the same for playing (0.15) and analysing (0.0). I already checked that for some positions you can get different results. For example this one (if I remember well) with 256Mb hash

2b1q3/p7/1p1p2kb/nPpN3p/P1P1P2P/6P1/5R1K/5Q2 w - -

e5 seems stronger than Rf6+ but both win I guess. Rybka 3 choose e5 or Rf6+ depending on if you play or analyse.

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Dr.Wael Deeb
Posts: 9635
Joined: Wed Mar 08, 2006 7:44 pm
Location: Amman,Jordan

Re: Any difference between analysis and engine play?

Post by Dr.Wael Deeb » Tue Sep 02, 2008 3:07 pm

genorb wrote:As Dr.Wael Deeb said, for most engine there is no different. But for Rybka 3 there is a small difference because the contempt factor is not the same for playing (0.15) and analysing (0.0). I already checked that for some positions you can get different results. For example this one (if I remember well) with 256Mb hash

2b1q3/p7/1p1p2kb/nPpN3p/P1P1P2P/6P1/5R1K/5Q2 w - -

e5 seems stronger than Rf6+ but both win I guess. Rybka 3 choose e5 or Rf6+ depending on if you play or analyse.
For analysing with Rybka 3,set the contempt factor to 0.0....
_No one can hit as hard as life.But it ain’t about how hard you can hit.It’s about how hard you can get hit and keep moving forward.How much you can take and keep moving forward….

genorb

Re: Any difference between analysis and engine play?

Post by genorb » Tue Sep 02, 2008 3:26 pm

Dr.Wael Deeb wrote:
genorb wrote:As Dr.Wael Deeb said, for most engine there is no different. But for Rybka 3 there is a small difference because the contempt factor is not the same for playing (0.15) and analysing (0.0). I already checked that for some positions you can get different results. For example this one (if I remember well) with 256Mb hash

2b1q3/p7/1p1p2kb/nPpN3p/P1P1P2P/6P1/5R1K/5Q2 w - -

e5 seems stronger than Rf6+ but both win I guess. Rybka 3 choose e5 or Rf6+ depending on if you play or analyse.
For analysing with Rybka 3,set the contempt factor to 0.0....
I know thanks, this was to answer to Kah Huat, Koh.

I was also mentioning this because if you run automatized test suites under, for example, the classic Shedder GUI, then you are using the playing mode and you are not analysing (I do not know about Fritz GUI). So at the end of some tests, I saw that Rybka 3 did not find the best move, then I loaded those positions and analyzed them and Rybka 3 found the solution. Then I understood that contempt can play a role. Of course Rybka 3 will not go from a bad move to a good one just because of this contempt issue I guess, but still there is some slight differences, especially for test suites if the GUI use play mode. The same would go for automatized game analysis under Shredder GUI I guess (I would have to check). I would not be surprised if the play mode is also used. This mean that with Shredder GUI (at least) if you want to use those automatized tools (that are nice by the way), it's perhaps better to create a new Rybka 3 personnality where you set contempt play to 0 instead of 0.15. This is what I did. I hope I was clear with that explanation... not sure though :)

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Dr.Wael Deeb
Posts: 9635
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Location: Amman,Jordan

Re: Any difference between analysis and engine play?

Post by Dr.Wael Deeb » Tue Sep 02, 2008 7:05 pm

genorb wrote:
Dr.Wael Deeb wrote:
genorb wrote:As Dr.Wael Deeb said, for most engine there is no different. But for Rybka 3 there is a small difference because the contempt factor is not the same for playing (0.15) and analysing (0.0). I already checked that for some positions you can get different results. For example this one (if I remember well) with 256Mb hash

2b1q3/p7/1p1p2kb/nPpN3p/P1P1P2P/6P1/5R1K/5Q2 w - -

e5 seems stronger than Rf6+ but both win I guess. Rybka 3 choose e5 or Rf6+ depending on if you play or analyse.
For analysing with Rybka 3,set the contempt factor to 0.0....
I know thanks, this was to answer to Kah Huat, Koh.

I was also mentioning this because if you run automatized test suites under, for example, the classic Shedder GUI, then you are using the playing mode and you are not analysing (I do not know about Fritz GUI). So at the end of some tests, I saw that Rybka 3 did not find the best move, then I loaded those positions and analyzed them and Rybka 3 found the solution. Then I understood that contempt can play a role. Of course Rybka 3 will not go from a bad move to a good one just because of this contempt issue I guess, but still there is some slight differences, especially for test suites if the GUI use play mode. The same would go for automatized game analysis under Shredder GUI I guess (I would have to check). I would not be surprised if the play mode is also used. This mean that with Shredder GUI (at least) if you want to use those automatized tools (that are nice by the way), it's perhaps better to create a new Rybka 3 personnality where you set contempt play to 0 instead of 0.15. This is what I did. I hope I was clear with that explanation... not sure though :)
Hi Fabian,
You were more than clear and I agree with you....
_No one can hit as hard as life.But it ain’t about how hard you can hit.It’s about how hard you can get hit and keep moving forward.How much you can take and keep moving forward….

genorb

Re: Any difference between analysis and engine play?

Post by genorb » Tue Sep 02, 2008 9:45 pm

Dr.Wael Deeb wrote: Hi Fabian,
You were more than clear and I agree with you....
Thanks!! :wink: Sometime I realize that my english is not always as good as I would like, this is why I am not always sure if I am clear :)

Kohflote
Posts: 200
Joined: Wed Sep 19, 2007 9:07 am
Location: Singapore

Re: Any difference between analysis and engine play?

Post by Kohflote » Wed Sep 03, 2008 12:22 am

Thank you, guys!! Your help is much appreciated.


Best Regards,
Kah Huat, Koh

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