What is difference between EGTB and EGBB?

[mrerk]

What is difference between EGTB and EGBB and why?

Eran Karu

[Dann Corbit]

In short, a bitbase (EGBB) encodes only win/lost/drawn in two bits and EGTB encodes more information like distance to mate or distance to conversion and what move you should make. In detail:
http://horizonchess.com/FAQ/Winboard/egtb.html

[ernest]

In short, a bitbase (EGBB) encodes only win/lost/drawn in two bits

Typically, using only bitbases won't help a program to win a KBNK ending, since practically any move is a win, but you will oscillate in the distance to Mate, since you don't have that info.

I just checked that with the new Toga/egbb...

[Dann Corbit]

In short, a bitbase (EGBB) encodes only win/lost/drawn in two bits

Typically, using only bitbases won't help a program to win a KBNK ending, since practically any move is a win, but you will oscillate in the distance to Mate, since you don't have that info.

I just checked that with the new Toga/egbb...

If I were king of the forest and I was writing a chess program, I would use bitbase files to find the win and as soon as bitbase win nodes became pv nodes, I would look them up in the EGTB.

[M ANSARI]

In short, a bitbase (EGBB) encodes only win/lost/drawn in two bits

Typically, using only bitbases won't help a program to win a KBNK ending, since practically any move is a win, but you will oscillate in the distance to Mate, since you don't have that info.

I just checked that with the new Toga/egbb...

If I were king of the forest and I was writing a chess program, I would use bitbase files to find the win and as soon as bitbase win nodes became pv nodes, I would look them up in the EGTB.

Exactly ... I am surprised that nobody seems to think about that.

[anst]

Are you sure that Shredder doesn't do this - it uses both its own format EGBBs and Nalimov.

Regards
Andreas

[ernest]

If I were king of the forest and I was writing a chess program, I would use bitbase files to find the win and as soon as bitbase win nodes became pv nodes, I would look them up in the EGTB.

Of course, but remember Toga cannot use Nalimov's EGTB because the corresponding Nalimov software is not open source...

[guyhaw]

The use of what are being called EGBBs, as a precursor to using EGTBs, has been proposed for some time, see articles in the ICGA Journal. I believe this is precisely what SHREDDER does now.
I have also proposed that EGBBs should be created as a precursor to creating the corresponding EGTB. It helps to know that one is not looking at a potential stm loss when retro'ing back to greater depths.