[Computer-go] ManyFaces swindled of victory?

David Fotland fotland at smart-games.com
Sat Nov 13 08:30:24 PST 2010

It's also a little dangerous to generalize from one example, because all
complex programs have bugs.  Sometimes a perceived general weakness is just
caused by a bug triggered by some peculiarity of that particular position.


In any case, I'm glad you posted this since it gives me a good example to
work from to improve the engine.




From: computer-go-bounces at dvandva.org
[mailto:computer-go-bounces at dvandva.org] On Behalf Of Don Dailey
Sent: Saturday, November 13, 2010 7:14 AM
To: computer-go at dvandva.org
Subject: Re: [Computer-go] ManyFaces swindled of victory?



On Sat, Nov 13, 2010 at 9:08 AM, terry mcintyre <terrymcintyre at yahoo.com>

Don, I'm enough of a go player to know that, in such a position, a 2d human
would trounce the kyu player, if given the middle game position to start
with - but I'd appreciate the views of a dan-level player.  MFGO in such
positions often fails to take care of its groups - even though it is far
stronger than I.


I'm not saying you are wrong,  I'm just trying to keep everyone honest.
It's just that the hair on the back of my neck sticks up when I see an idea
start to become gospel and I hope that as we figure all of this out we are
not making incorrect assumptions that will set us back.     


Here is what bothers me about this:


You saw a position and said, "in such a position" a 2d human would trounce
the kyu player.  Not only are you making a judgement about a specific
position (which may or may not be true),  but you are generalizing it based
on what you subjectively think "such a position" means.     You have used at
least 2 subjective opinions, linked them together and use this to draw a
conclusion.   (Presumably this is just a tentative conclusion,  a
hypothesis, which I think is the right way to think about such things.)    


Don't forget that as humans we have very strong pattern recognition
facilities.   We can see animals and all kinds of various objects in cloud
formations and studies have shown that we tend to find patterns in random
things.   This often tends to make us draw conclusions very quickly based on
little evidence or just plain gut feelings as witnessed by the large number
of criminal cases that were incorrectly judged.      This is both a strength
and a weakness that we have but it is the source of massive amounts of
incorrect "common wisdom."


How many times have programmers here observed something wrong with the way
their program plays,  made a judgement about WHY the program is playing
badly, and then implemented a fix which clearly addresses the problem they
think they are seeing - and lo and behold the program is now weaker?     It
was worth a try but it's way too easy for such a chain of reasoning to be


If you really want to see my point in action,  watch the stock market and
the way each days activity is explained at the end of the day.    They will
say something like,  "The nasdaq today was down based on fears of
recession."     The stock market is incredibly complex,  and yet the
analysts ALWAYS seem to know the exact explanation for why it went up or
down some slight amount.     And that explanation is presented as a
statement of fact,  the reason why.  


Sorry I'm being so picky about this but it drives me crazy, it's one of my
peeves.   You didn't do anything wrong :-)














Dave Fotland himself has observed similar results; there are many game
records to back up this contention. A while back, I posted about a player
who has a very high winrate against MFGO - it looked like his account did
nothing else but play computer programs. 


Strong humans organize and prioritize things differently than (current)
strong programs.


If you can keep track of things at blitz speed, and set up complicated
fights with large unsettled groups, and patiently encroach on a program's
eyespace ( even DDK players know that a dragon, however large, still
requires two eyes to live ), you can often give a program a good drubbing.

Earlier, we had a post regarding a shogi program which combines the votes of
four other programs. 


Given that processor cores are now abundant, and that UCT programs have
trouble using all that horsepower, I wonder if some cores should look at the
board in an entirely different way and, every now and then, generate "Danger
,Will Robinson" signals which trump the usual winrate algorithms - or at
least tweak them toward safety moves. 


Is there a way to combine such disparate information into a coherent picture
of the board? 


Terry McIntyre <terrymcintyre at yahoo.com>

Unix/Linux Systems Administration
Taking time to do it right saves having to do it twice.




From: Don Dailey <dailey.don at gmail.com>
To: computer-go at dvandva.org
Sent: Sat, November 13, 2010 8:18:19 AM
Subject: Re: [Computer-go] ManyFaces swindled of victory?

On Fri, Nov 12, 2010 at 9:24 PM, terry mcintyre <terrymcintyre at yahoo.com>

This is a curious game - a 3 stone game betwixt ManyFaces and a 2 kyu


It looks to my eye as if MFGO was well ahead in the middle game, yet managed
to snatch defeat from the jaws of victory. 


Black has many unsettled groups; usually a stronger player causes much grief
in situations like this, but black managed to turn around and swallow up not
one but several white groups. 


Most interesting. I think this confirms an earlier thread - when there are
several semeai on the board, MCT-based strategies get into difficulties. 


Are you sure of this?    I think it is human nature to try to make sense of
things and create general rules and principles to explain what we think we
may be observing.   It's also human nature to often be wrong about it.
The first time an idea is skillfully presented it tends to carry extra
(sometimes undeserved) weight because everyone else interprets what they see
in terms of that and it gets repeated over and over till it becomes the
de-facto sound bite that propagates itself.  


Maybe it's completely true and there is no dispute or it's obvious -
unfortunately I'm not a go player so I'm in no position to add my 2 cents
but I would be very cautious about making  general statements about the
relative strengths and weaknesses of humans compared to computers.      


I know from experience with chess for many decades that peoples perception
of the computers strengths and weaknesses were constantly misinterpreted,
very often based on a just a game or two someone played.     People were
just trying to make sense of it, but they got it wrong a lot.    In one case
in the 80's my program played a master and lost tactically and believe it or
not the master felt the program was strong positionally but weak tactically
(because he beat it with a tactical shot) even though we now understand it's
completely the opposite.    The truth of the matter was that the computer
was simply a lot weaker than this particular player so it was inferior all
the way around.  


If your supposition is true, then it's a good thing to know because perhaps
it can be addressed.    Or it might end up being one of those things that
diminishes in importance over time as computers get generally stronger and
stronger.    In chess, computers have always been weaker in true positional
understanding (even to this day) but we have added so many layers of
strength that this weakness is only a relative thing.   It's weaker than
other parts of it's game,  but not so weak that anyone can easily take
advantage of it.   Most computer games resemble Grandmaster games in the
quality of positional play.






I think strong human players tend to have a better grasp of "this particular
fight is settled, no need to study it further until a liberty is removed (in
which case respond now!); let's focus on this other fight instead . . ."




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