Author: Dieter Buerssner
Date: 15:57:12 01/19/04
Go up one level in this thread
On January 19, 2004 at 17:51:27, Robert Hyatt wrote:
>Someone else pointed out that it is possible that the move was a fail-high
>or fail-low move. Printing out a PV on such moves is impossible and you get
>_lots_ of garbage most of the time.
I got the feeling, that printing out "PVs" (they are no "real" PVs, as we both
know, but may be called "refutation lines") is surprisingly often not that full
of garbage, as one might expect (when using fail soft alpha-beta). I would
certainly not call it impossible. It gives more info (which one can ignore, and
is back to the same, when not printing it, so no real disadvantage).
I just tried the Nf5 pos posted here recently.
91388636 2:08.1 -0.50 11t 16.Bxb7 Qxb7 17.Na5 Qd5 18.Nc4 Bd8H 19.Nxb3H
Qxd1H 20.Rfxd1H O-OH 21.Nd6H {-80}
145628113 3:24.9 -0.49 11t+ 16.Nf5 exf5 17.Bd4 Bxg2 18.Bxa7 Bd6
[Outside of window, probably now the line continues with "null", which my engine
will not display by default. For debugging even displaying that and remaining
moves can be interesting, to see at least a sample line that failed high.]
152281645 3:38.1 0.01 11++ 16.Nf5 exf5 17.Bd4 Bxg2 18.Bxa7 Bxf1 19.Nd6+
Bxd6 20.Qxd6 Nc6 21.Rxc6 b2 22.Qe5+ Kf8H
23.Bc5+H {HT} {1}
[alternative would be to just print Nf5!!]
170526494 4:06.5 0.29 11t 16.Nf5 exf5 17.Bd4 Bxg2 18.Bxa7 Bxf1 19.Nd6+
Bxd6 20.Qxd6 Nc6 21.Rxc6 Ne4 22.Qe5+ Kf8 23.Rc7
{1}
180964542 4:19.9 0.29 11. 16.Nf5 exf5 17.Bd4 Bxg2 18.Bxa7 Bxf1 19.Nd6+
Bxd6 20.Qxd6 Nc6 21.Rxc6 Ne4 22.Qe5+ Kf8 23.Rc7
{1}
223379378 5:30.2 0.69 12++ 16.Nf5 exf5 17.Bd4 Bxg2 18.Bxa7 Bxf1 19.Nd6+
Bxd6 20.Qxd6 Nc6 21.Rxc6 Nd5 22.Bc5 Rd8 23.Qe5+
Ne7 24.Kxf1 dxc6 25.Qxe7# {191}
[And here, too]
247811846 6:11.8 0.94 12t 16.Nf5 exf5 17.Bd4 Bxg2 18.Bxa7 Bxf1 19.Nd6+
Bxd6 20.Qxd6 Nc6 21.Rxc6 Ne4 22.Qe5+ Kf8 23.Rc7
Bc4 24.Bc5+ Kg8 {HT} {1}
At least the start of the lines, seems to look very reasonable (while it is all
three times where noted, outside of the window). I also measured the overhead
some time ago. Even when updating such "PVs" when outside of the window, the
overhead seems totally neglible to me (and it will be updated then many more
times, than in the case where updating it only when the score is inside the
window).
Regards,
Dieter
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