Depth of book affects some engines rating more than others

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Michael Sherwin
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Depth of book affects some engines rating more than others

Post by Michael Sherwin »

I have noticed this before. That Romi's rating can vary several hundred points depending on how deep the book is that is used. A shallow book can cause Romi to be rated under 2300 and a deep book can result in Romi getting a rating over 2600. These numbers represent the extreme. Other engines as well seem to experiance the same.
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Uri Blass
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Re: Depth of book affects some engines rating more than othe

Post by Uri Blass »

Michael Sherwin wrote:I have noticed this before. That Romi's rating can vary several hundred points depending on how deep the book is that is used. A shallow book can cause Romi to be rated under 2300 and a deep book can result in Romi getting a rating over 2600. These numbers represent the extreme. Other engines as well seem to experiance the same.
I guess that a deep book can result in Romi losing games because deep book can include many blunders that Romi is not going to do without book.

Uri
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Ovyron
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Re: Depth of book affects some engines rating more than othe

Post by Ovyron »

Uri Blass wrote:I guess that a deep book can result in Romi losing games because deep book can include many blunders that Romi is not going to do without book.

Uri
It can, but if the 2300-2600 figure is right, that means that in most cases, Romi is going to play worse than the book, so these cases are going to offset the cases in where the book plays worse than Romi.
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pedrox
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Re: Depth of book affects some engines rating more than othe

Post by pedrox »

What is a shallow book and what is a deep book?

Sahllow book = 7 moves and deep book = 13?

In CCRL, in long time control, in a division the engines have a strength rather equal (+-100), a deep book may give a decisive advantage to the engine almost in theory weaker, there is little margin for manoeuvre.
Marc Lacrosse
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Re: Depth of book affects some engines rating more than othe

Post by Marc Lacrosse »

pedrox wrote: deep book = 13?
On Playchess, top accounts have forced lines in their book going far in the endgame in some variations, sometimes near 100 plies deep ...

Some Najdorf variations have been analysed to death... and it is extremely dangerous to leave established main lines : there are seemingly correct moves against which a clear refutation has been found where the decisive advantage is not clear before more than twenty plies ...

Against such books playing on its own or with a short book is a sure way to defeat for any player.

Marc
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Re: Depth of book affects some engines rating more than othe

Post by Tony Thomas »

There are times when Romi goes 80 ply deep, under those circumstances, I have never seen Romi lose. Even against an extremly strong opponet, with an 80 ply deep line, and the extra time helps Romi at least draw the game.
Michael Sherwin
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Re: Depth of book affects some engines rating more than othe

Post by Michael Sherwin »

Uri Blass wrote:
Michael Sherwin wrote:I have noticed this before. That Romi's rating can vary several hundred points depending on how deep the book is that is used. A shallow book can cause Romi to be rated under 2300 and a deep book can result in Romi getting a rating over 2600. These numbers represent the extreme. Other engines as well seem to experiance the same.
I guess that a deep book can result in Romi losing games because deep book can include many blunders that Romi is not going to do without book.

Uri
The observation is that when Romi reaches the late middlegame with a good position then she can hold her own against 2600 rated programs. When a really deep book (40 to 60 plies for both engines) is used then Romi reaches the late middlegame in good shape much more often.
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bob
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Re: Depth of book affects some engines rating more than othe

Post by bob »

Michael Sherwin wrote:I have noticed this before. That Romi's rating can vary several hundred points depending on how deep the book is that is used. A shallow book can cause Romi to be rated under 2300 and a deep book can result in Romi getting a rating over 2600. These numbers represent the extreme. Other engines as well seem to experiance the same.
That is just one reason why you should test without books at all, and use a set of starting positions that you can repeat each time you make a programming change.