I store everythingTony wrote: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
so the information is just available. Just stack if a move is a PVS move from the hash table.Your second paragraph says it all, that's what's happening.Uri Blass wrote: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
The above example is not totally correct, consider this PV line:ed wrote:Your second paragraph says it all, that's what's happening.Uri Blass wrote: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
The advantage of this extension (with the exception code) is that it only extend reasonable well move sequences with hardly any garbage. After all, it's based on the best moves from the hash table which seldom contain garbage.
Ed
Hi Ed,ed wrote:Hi Mike,Michael Sherwin wrote:Hi Ed,ed wrote: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
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
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
Hi Ed,ed wrote:The above example is not totally correct, consider this PV line:ed wrote:Your second paragraph says it all, that's what's happening.Uri Blass wrote: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
The advantage of this extension (with the exception code) is that it only extend reasonable well move sequences with hardly any garbage. After all, it's based on the best moves from the hash table which seldom contain garbage.
Ed
1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.0-0
1..e5 and 2.Nf3 is a pair (count++)
2.Nf3 and 2..Nc5 is a pair (count++)
etc....
When count=4 extend
Ed
That was basicly what I meant. I didn't see what having a hashmove had to do with it. Just counting the amount of pv nodes in a row should do it so I was wondering if this hash move count added something.Ron Murawski wrote:Hi Ed,ed wrote:The above example is not totally correct, consider this PV line:ed wrote:Your second paragraph says it all, that's what's happening.Uri Blass wrote: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
The advantage of this extension (with the exception code) is that it only extend reasonable well move sequences with hardly any garbage. After all, it's based on the best moves from the hash table which seldom contain garbage.
Ed
1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.0-0
1..e5 and 2.Nf3 is a pair (count++)
2.Nf3 and 2..Nc5 is a pair (count++)
etc....
When count=4 extend
Ed
Isn't this the same as saying "extend the pv line by one ply at ply 8"?
And now, since your counter is reset to zero:Ron
- * If the pv does not change, the next possible extension would occur at ply 16.
* If the pv *did* change, let's say at ply 3, then the next pv extension would occur at ply 3+8 = 11.
I do not see how you get 8Ron Murawski wrote:Hi Ed,ed wrote:The above example is not totally correct, consider this PV line:ed wrote:Your second paragraph says it all, that's what's happening.Uri Blass wrote: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
The advantage of this extension (with the exception code) is that it only extend reasonable well move sequences with hardly any garbage. After all, it's based on the best moves from the hash table which seldom contain garbage.
Ed
1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.0-0
1..e5 and 2.Nf3 is a pair (count++)
2.Nf3 and 2..Nc5 is a pair (count++)
etc....
When count=4 extend
Ed
Isn't this the same as saying "extend the pv line by one ply at ply 8"?
And now, since your counter is reset to zero:Ron
- * If the pv does not change, the next possible extension would occur at ply 16.
* If the pv *did* change, let's say at ply 3, then the next pv extension would occur at ply 3+8 = 11.
Hi Uri,Uri Blass wrote:I do not see how you get 8Ron Murawski wrote:Hi Ed,ed wrote:The above example is not totally correct, consider this PV line:ed wrote:Your second paragraph says it all, that's what's happening.Uri Blass wrote: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
The advantage of this extension (with the exception code) is that it only extend reasonable well move sequences with hardly any garbage. After all, it's based on the best moves from the hash table which seldom contain garbage.
Ed
1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.0-0
1..e5 and 2.Nf3 is a pair (count++)
2.Nf3 and 2..Nc5 is a pair (count++)
etc....
When count=4 extend
Ed
Isn't this the same as saying "extend the pv line by one ply at ply 8"?
And now, since your counter is reset to zero:Ron
- * If the pv does not change, the next possible extension would occur at ply 16.
* If the pv *did* change, let's say at ply 3, then the next pv extension would occur at ply 3+8 = 11.
1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.0-0
1.e4 e5 is a pair(count++)
1..e5 and 2.Nf3 is a pair (count++)
2.Nf3 and 2..Nc6 is a pair (count++)
Nc6 3.Bb5 is a pair(count++)
You extend by one ply in the 5th ply of the pv.
Uri
PVS extention, a quick test.Michael Sherwin wrote:Hi Ed,ed wrote:Hi Mike,Michael Sherwin wrote:Hi Ed,ed wrote: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
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
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 will try this extention again and will be very careful to do it the way that you say to do it. Then I will report back.
Mike
Code: Select all
if(h->p && h->p->m != noMove.m) extendBy += 25; // one-fourth ply
Code: Select all
// This is the RomiChess extention/reduction method.
if(extendBy >= 100) {
depth++;
extendBy -= 100;
} else
if(extendBy <= -100) {
depth--;
extendBy += 100;
}
Code: Select all
if(extendBy < 100 && h->p && h->p->depth + 2 >= depth && h->p->m != noMove.m) extendBy += 25;
Ah-ah! But I am reading this thread as well!Michael Sherwin wrote:After 10 games (way to few) versus Hamsters 0.2 it is RomiChess +8 -2 =0! And Romi had a won game during one of the games that she lost, but succumbed to a king-attack to which she is still vulnerable. This is a new record for Romi in the first 10 games versus Hamsters 0.2.