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by mcostalba
Fri Aug 25, 2017 12:49 pm
Forum: Computer Chess Club: General Topics
Topic: Natural TB
Replies: 330
Views: 66456

Re: Natural TB (take 2)

syzygy wrote:Contrary to what you think, this is not speculation.
You also wrote "The reason why it is there is to handle the case where DTZ is not available and the root position is in the TBs and winning."

Isn't this the same case...
by mcostalba
Fri Aug 25, 2017 10:43 am
Forum: Computer Chess Club: General Topics
Topic: Natural TB
Replies: 330
Views: 66456

Re: Natural TB (take 2)

syzygy wrote: Which only works because the non-winning moves are tossed out first...
Yes and we toss out the non-winning moves too...not at root but at the immediately next child node, does this is really different?
by mcostalba
Fri Aug 25, 2017 10:40 am
Forum: Computer Chess Club: General Topics
Topic: Natural TB
Replies: 330
Views: 66456

Re: Natural TB (take 2)

Have you talked about your ideas with Joona? He does seem to have good insight in this area (judging from some posts he made quite some time ago). You might be more willing to accept his words. I am willing to accept the words of everybody, especially your words considered that you are the original...
by mcostalba
Fri Aug 25, 2017 10:29 am
Forum: Computer Chess Club: General Topics
Topic: Natural TB
Replies: 330
Views: 66456

Re: Natural TB (take 2)

And indeed, everything must be tested. It is just as speculative to think the proposed strategy has any benefits at all. Yes, currently I have verified on some test positions that with this code there are no sacrifice, TB scores, etc. But more test positions are needed possibly by other interested ...
by mcostalba
Fri Aug 25, 2017 10:07 am
Forum: Computer Chess Club: General Topics
Topic: Natural TB
Replies: 330
Views: 66456

Re: Natural TB (take 2)

+ if ( abs(v) <= drawScore + || !ttHit + || (v < -drawScore && ttValue > -VALUE_KNOWN_WIN) + || (v > drawScore && ttValue < VALUE_KNOWN_WIN)) + { < cut> + } That is what I have been using in Matefinder for quite some time now. - } This is also very interesting. I s...
by mcostalba
Fri Aug 25, 2017 9:57 am
Forum: Computer Chess Club: General Topics
Topic: Natural TB
Replies: 330
Views: 66456

Re: Natural TB (take 2)

Well, if the root is a win then every searched line will be reduced, and reducing everything doesn't alter the shape of the tree, but just causes the engine to lie more about the depth it reaches. Yes, that's correct. Please note that this is what happens already today with current implementation: ...
by mcostalba
Fri Aug 25, 2017 9:28 am
Forum: Computer Chess Club: General Topics
Topic: Natural TB
Replies: 330
Views: 66456

Re: Natural TB (take 2)

That your particular experiment did not work out does not say much. Unfortunately your answer say even less. Removing all TB probing code is even more simple and effective in this regard... Ditto. Obviously disabling TB probing introduces search instability and it prevents SF from finding the winni...
by mcostalba
Fri Aug 25, 2017 9:07 am
Forum: Computer Chess Club: General Topics
Topic: Natural TB
Replies: 330
Views: 66456

Re: Natural TB (take 2)

hgm wrote:see the TB-win, and thus fail high.
See the tb-win and DO NOT fail high (but keep searching at reduced depth and return normal search score).
by mcostalba
Fri Aug 25, 2017 8:33 am
Forum: Computer Chess Club: General Topics
Topic: Natural TB
Replies: 330
Views: 66456

Re: Natural TB (take 2)

Something else I do in Matefinder is to not stop probing even after we reach TBs in Root. Since you no longer return early for non-draws, you still search, but you get a nice speed up (in depth) due to all the draw cutoffs. This seems a nice idea. Indeed with natural TB scheme I am thinking of remo...
by mcostalba
Fri Aug 25, 2017 8:22 am
Forum: Computer Chess Club: General Topics
Topic: Natural TB
Replies: 330
Views: 66456

Re: Natural TB (take 2)

(And of course not probing in the PV comes with its own set of undesirable effects.) I don't probe in PV for 2 reasons: 1. Align to what we do in TT, where we don't cut-off in PV after a TT probing (this is not mandatory, many engines do cut-off and also SF in the past did, but we move to current s...