PVS extension up

[ed]

When picking up my work again on the chess page I to my astonishment noticed I had forgotten to mention a probable important extension. I am curious how many of you use a similar approach.

http://www.top-5000.nl/authors/rebel/chess840.htm

Ed

[Michael Sherwin]

When picking up my work again on the chess page I to my astonishment noticed I had forgotten to mention a probable important extension. I am curious how many of you use a similar approach.

http://www.top-5000.nl/authors/rebel/chess840.htm

Ed

Hi Ed,

Yes I have tried that type extention and it was inconclusive.

About extentions in general. When I first released RomiChess it only had a check extention and a mate threat extention and was already a rather strong program. I thought that if now, I were to put in all the right extentions, then it would take another big jump in ELO. However, no further extentions helped. I was getting very frustrated. Then Prof. Hyatt wrote that he was dropping some extentions as modern hardware was so fast that the extentions no longer helped and may even be counter productive. Given my experiance, I tend to agree.

Mike

[Tony]

When picking up my work again on the chess page I to my astonishment noticed I had forgotten to mention a probable important extension. I am curious how many of you use a similar approach.

http://www.top-5000.nl/authors/rebel/chess840.htm

Ed

Hi Ed,

Yes I have tried that type extention and it was inconclusive.

About extentions in general. When I first released RomiChess it only had a check extention and a mate threat extention and was already a rather strong program. I thought that if now, I were to put in all the right extentions, then it would take another big jump in ELO. However, no further extentions helped. I was getting very frustrated. Then Prof. Hyatt wrote that he was dropping some extentions as modern hardware was so fast that the extentions no longer helped and may even be counter productive. Given my experiance, I tend to agree.

Mike

Check extensions seem to be the only ones that are clear winners. After that, they bring a lot less, and they seem to need retesting after every engine change.

Tony

[Tony]

When picking up my work again on the chess page I to my astonishment noticed I had forgotten to mention a probable important extension. I am curious how many of you use a similar approach.

http://www.top-5000.nl/authors/rebel/chess840.htm

Ed

Hi Ed,

you wrote you're not happy with the passed pawns scoring.

Maybe you left out some stuff for simplicity, but there seems to be a major flaw in your scoring.
When a passed pawn is defended from behind by a rook (or queen) it will not show up in your attackboard on the square ahead of the pawn. So the pawn might look like it can't advance while it actually could.

Tony

[Tony]

When picking up my work again on the chess page I to my astonishment noticed I had forgotten to mention a probable important extension. I am curious how many of you use a similar approach.

http://www.top-5000.nl/authors/rebel/chess840.htm

Ed

Hi Ed,

the

if (BB[rank+1] && WB[rank+1]) break;

stuff, should be

if (BB[rank+1] && !WB[rank+1]) break;

Tony

[ed]

When picking up my work again on the chess page I to my astonishment noticed I had forgotten to mention a probable important extension. I am curious how many of you use a similar approach.

http://www.top-5000.nl/authors/rebel/chess840.htm

Ed

Hi Ed,

you wrote you're not happy with the passed pawns scoring.

Maybe you left out some stuff for simplicity, but there seems to be a major flaw in your scoring.
When a passed pawn is defended from behind by a rook (or queen) it will not show up in your attackboard on the square ahead of the pawn. So the pawn might look like it can't advance while it actually could.

Tony

Good thinking Tony, I see you have done your homework quite well but..........

Something I did not describe (because I believe it is out of the realm of the page) is that during the scanning WB (and BB) are updated too in case of a vertical xray of a white rook and white pawn, that is, if the square is empty.

Example: from the start position, squares h3, h4 and h5 are incremented with 1 because of the xray wrh1 and wph2.

To be complete: I don't do it for Queens because queens are supposed to support a passed pawn in front, contrary to rooks.

Ed

[ed]

You are absolutely right, wrong ASM to C translation!

Thx

Ed

When picking up my work again on the chess page I to my astonishment noticed I had forgotten to mention a probable important extension. I am curious how many of you use a similar approach.

http://www.top-5000.nl/authors/rebel/chess840.htm

Ed

Hi Ed,

the

if (BB[rank+1] && WB[rank+1]) break;

stuff, should be

if (BB[rank+1] && !WB[rank+1]) break;

Tony

[ed]

When picking up my work again on the chess page I to my astonishment noticed I had forgotten to mention a probable important extension. I am curious how many of you use a similar approach.

http://www.top-5000.nl/authors/rebel/chess840.htm

Ed

Hi Ed,

Yes I have tried that type extention and it was inconclusive.

About extentions in general. When I first released RomiChess it only had a check extention and a mate threat extention and was already a rather strong program. I thought that if now, I were to put in all the right extentions, then it would take another big jump in ELO. However, no further extentions helped. I was getting very frustrated. Then Prof. Hyatt wrote that he was dropping some extentions as modern hardware was so fast that the extentions no longer helped and may even be counter productive. Given my experiance, I tend to agree.

Mike

Hi Mike,

The subject awakened my curiosity and so I ran a quick eng-eng match without the PVS extension. The result was considerable worse than with the default setting (PVS=ON). So it seems the PVS extension is still working.

Ed

[Tony]

When picking up my work again on the chess page I to my astonishment noticed I had forgotten to mention a probable important extension. I am curious how many of you use a similar approach.

http://www.top-5000.nl/authors/rebel/chess840.htm

Ed

Hi Ed,

Yes I have tried that type extention and it was inconclusive.

About extentions in general. When I first released RomiChess it only had a check extention and a mate threat extention and was already a rather strong program. I thought that if now, I were to put in all the right extentions, then it would take another big jump in ELO. However, no further extentions helped. I was getting very frustrated. Then Prof. Hyatt wrote that he was dropping some extentions as modern hardware was so fast that the extentions no longer helped and may even be counter productive. Given my experiance, I tend to agree.

Mike

Hi Mike,

The subject awakened my curiosity and so I ran a quick eng-eng match without the PVS extension. The result was considerable worse than with the default setting (PVS=ON). So it seems the PVS extension is still working.

Ed

I was wondering how you get 2 moves in a row from hashtable. One of the 2 positions would be a fail low node where you normally don't have a hashmove.

Do you store bestmoves in fail low nodes ? Or do you keep the bestmoves on fail low nodes when they previously were fail highs nodes ?

Tony

[Uri Blass]

When picking up my work again on the chess page I to my astonishment noticed I had forgotten to mention a probable important extension. I am curious how many of you use a similar approach.

http://www.top-5000.nl/authors/rebel/chess840.htm

Ed

Hi Ed,

Yes I have tried that type extention and it was inconclusive.

About extentions in general. When I first released RomiChess it only had a check extention and a mate threat extention and was already a rather strong program. I thought that if now, I were to put in all the right extentions, then it would take another big jump in ELO. However, no further extentions helped. I was getting very frustrated. Then Prof. Hyatt wrote that he was dropping some extentions as modern hardware was so fast that the extentions no longer helped and may even be counter productive. Given my experiance, I tend to agree.

Mike

Hi Mike,

The subject awakened my curiosity and so I ran a quick eng-eng match without the PVS extension. The result was considerable worse than with the default setting (PVS=ON). So it seems the PVS extension is still working.

Ed

I was wondering how you get 2 moves in a row from hashtable. One of the 2 positions would be a fail low node where you normally don't have a hashmove.

Do you store bestmoves in fail low nodes ? Or do you keep the bestmoves on fail low nodes when they previously were fail highs nodes ?

Tony

I think that it is easy to get 2 moves in a row from hashtable in case that you have an exact score and if I understand correctly pvs extensions are about extending moves that have exact score.

If the pv is 1.e4 e5 2.Nf3 Nc6 then in the next search you can extend the position after 1.e4 e5 2.Nf3 Nc6 by one ply.

I did not try it and maybe I do not understand correctly what Ed means by PVS extensions so I think that some chess examples can help to understand the meaning of it.

Uri