As though they were pondering

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Frank Quisinsky
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Re: As though they were pondering

Post by Frank Quisinsky » Fri Jul 23, 2010 1:32 pm

Hi Gabor,

you are speaking about an advantage for testers!

All bugs from available clones, clones which are available in the next times (I am sure around 100 Ipp. Family clones will follow) we known before ...

:-)

One second after such a new clone is available, "clone-fans" can reported the bugs directly before testing. And perhaps, some days one of the "cloners" are able to fix such things, but I can't believe it.

For myself the right word for such persons are:
Programmer toddlers group :-)

We all have to learn ...
Its not negativ, just beginning ... in this case with programming!

With other words, all of this engines comes probable with the same bugs. What we get is ... which each of the thousand versions new bugs gratis. The ponder bug is a known good example.

Perhaps a realtiy chess programmer can make for "cloners" a little cours to "Ponder" ... this would be great and I am sure the clone-fans will be happy too.

Interesting that Zappa have the same. I am sure it's random in the case of Zappa.

In Winboard times we collect for each engine other bugs. In times today we find out that different bugs are the same.

Best
Frank
I like computer chess!

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Houdini
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Re: As though they were pondering

Post by Houdini » Fri Jul 23, 2010 1:57 pm

SzG wrote:I can see that sometimes Houdini makes an immediate move (0 thinking time) when it is not at all an obvious move. I have seen this behaviour only from two engines before: Rybka and Zappa. I wonder why.
The primary goal of the "instant move" is to win some time on a fairly obvious move (obvious for the engine, not necessarily for a human observer), it's only used when previous analysis has shown that the move to play is significantly better than the alternatives.

As your title suggests the feature is indeed comparable to a ponder hit, not based on the thinking during the opponent's time but on the thinking from the previous own move.
The technique entails a small risk, but most of the time it works very well, even in long TC matches (e.g. as currently hosted by Martin Thoresen).

Robert

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Houdini
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Re: As though they were pondering

Post by Houdini » Fri Jul 23, 2010 2:17 pm

SzG wrote:What I don't understand is why the engine does not make an instant move when it is entirely obvious, e.g. recapturing a queen.
Most of the time it does, but quite often there are different ways to capture, or a zwischenzug which a human player intuitively doesn't want or need to explore, unlike the engine.
Another point is that you don't really want to play several successive instant moves, as the search may become too shallow. It's a rather delicate balance between winning some time and the risk that the evaluation at lower search depth is not accurate enough.

Robert

bob
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Re: As though they were pondering

Post by bob » Fri Jul 23, 2010 4:16 pm

SzG wrote:I can see that sometimes Houdini makes an immediate move (0 thinking time) when it is not at all an obvious move. I have seen this behaviour only from two engines before: Rybka and Zappa. I wonder why.
Crafty will do it too. If there is only one legal move to make, it will move instantly...

bob
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Re: As though they were pondering

Post by bob » Fri Jul 23, 2010 7:33 pm

SzG wrote:
bob wrote:
SzG wrote:I can see that sometimes Houdini makes an immediate move (0 thinking time) when it is not at all an obvious move. I have seen this behaviour only from two engines before: Rybka and Zappa. I wonder why.
Crafty will do it too. If there is only one legal move to make, it will move instantly...
Almost all engines do it. I refer to a situation where there are several legal moves and the engine immediately selects one of them.
If you mean "instantly" and "without pondering" then that might be foolish. Crafty has always had an "easy move" mode where it will play an obvious move using much less than normal time. Say you play QxQ and there is only one way to respond. But sometimes an "easy move" can be deceiving, such as when your opponent appears to leave a piece hanging and there is only one way to capture it. But if you do, you enter a deep trap that loses. Moving too quickly sets you up for those kinds of positions.

I would never move instantly, pondering off, unless there is only one legal move. Anything else deserves a reasonable search, even if not a full search.

rainhaus
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Re: As though they were pondering

Post by rainhaus » Fri Jul 23, 2010 8:07 pm

Houdini wrote:
SzG wrote:I can see that sometimes Houdini makes an immediate move (0 thinking time) when it is not at all an obvious move. I have seen this behaviour only from two engines before: Rybka and Zappa. I wonder why.
The primary goal of the "instant move" is to win some time on a fairly obvious move (obvious for the engine, not necessarily for a human observer), it's only used when previous analysis has shown that the move to play is significantly better than the alternatives.

As your title suggests the feature is indeed comparable to a ponder hit, not based on the thinking during the opponent's time but on the thinking from the previous own move.
The technique entails a small risk, but most of the time it works very well, even in long TC matches (e.g. as currently hosted by Martin Thoresen).

Robert
An interesting question and an informative answer, indeed. Well, I noticed these 'instant moves' with other engines, too. With the 'Ippo' familiy, for sure, but also with two ore three of the GGT-group, Fritz 12, Shredder 12, Naum 4.. and Zappa Mexico II. Primarily I thought of a hidden pondering, not knowing exactly how this should work at all :)
Firebird shows a parameter "Move On Ponderhit" with the three options "never, sometimes, always". I don't know if it concerns an "Instant Move" as you have described, or the case of real pondering only?
I guess the instant move technique is an efficient one, at least statistically seen, and its definitely anything but a bug or the event of an 'only legal move'
rn
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