Check out Atomic Chess, our featured variant for November, 2024.


[ Help | Earliest Comments | Latest Comments ]
[ List All Subjects of Discussion | Create New Subject of Discussion ]
[ List Earliest Comments Only For Pages | Games | Rated Pages | Rated Games | Subjects of Discussion ]

Single Comment

Piece Values[Subject Thread] [Add Response]
H. G. Muller wrote on Mon, May 26, 2008 04:47 PM UTC:
Derek Nalls:
| Nonetheless, completing games of CRC (where a long, close, 
| well-played game can require more than 80 moves per player) 
| in 0:24 minutes - 36 minutes does NOT qualify as long or even, 
| moderate time controls.  In the case of your longest 36-minute games, 
| with an example total of 160 moves, that allows just 13.5 seconds per 
| move per player.  In fact, that is an extremely short time by any 
| serious standards.  

In my experience most games on the average take only 60 moves (perhaps
because of the large strength difference of the players). As early moves
are more important for the game result as late moves (even the best moves
late in the game do not help you if your position is already lost), most
engines use 2.5% of the remaining time for their next move (on average,
depending on how the iterations end compared to the target time). That
would be nearly 54 sec/move at 36 min/game in the decisive phase of the
game. That is more than you thought, but admittedly still fast. Note,
however, that I also played 60-min games in the General Championship
(without time odds), and that Joker80 confirms its lead over the
competitors it manifested at faster time controls.

But I don't see the point: Joker80's strength increases with time as
expected, in the range from 0.4 sec to 36 sec per move, in a regular and
theoretically expected way. This is over the entire range where I tested
the dependence of the scoring percentage of various material imbalances,
which extended to only 15 sec/move, and found it to be independent of TC.
So your 'explanation' for the latter phenomenon is just nonsense. The
effect you mention is observed NOT to occur, and thus cannot explain
anything that was observed to occur.

Now if you want to conjecture that this will all miraculously become very
different at longer TC, you are welcome to test it and show us convincing
results. I am not going to waste my computer time on such a wild and
expensive goose chase. Because from the way I know the engines work, I
know that they are 'scalable': their performance at 10 ply results from
one ply being put in front of 9-ply search trees. And that extra ply will
always help. If they have good 9-ply trees, they will have even better
10-ply trees. But you don't have to take my word for it. You have the
engine, and if you don't want to believe that at 1 hour per move you will
get the same win probability as at 1 sec/move, or that at 1 hour per move
it won't beat 10 min//move, just play the games, and you will see for
yourself. It would even be appreciated if you publish the games here or on
your website. But, needless to say, one or two games won't convince anyone
of anything.

| 'since I am not a computer chess programmer, I cannot possibly 
| know what I am talking about when I dare criticize an important 
| working of your Joker80 program'
Well, you certainly make it appear that way. As, despite the elaborate
explanation I gave of why programs derive extra strength from this
technique, you still draw a conclusion that in practice was already shown
to be 100% wrong earlier. And if you think you will run into the problem
you imagine at enormously longer TC, well, very simple: don't use
Joker80, but use some other engine. You are on your own there, as I am not
specifically interested in extremely long TC. There is always a risk in
using equipment outside the range of conditions for which it was designed
and tested, and that risk is entirely yours. So better tread carefully,
and make sure you rule out the percieved dangers by concise testing.

| You must decide upon and define the primary function of your 
| Joker80 program.

I do not see the dilemma you sketch. The purpose is to play ON AVERAGE the
best possible move. If you do that, you have the best chance to win the
game. If I can achieve that through a non-deterministic algorithm better
than through a deterministic one, I go for the nondeterministic method.
That it also diversifies play, and makes me less sensitive to prepared
openings from the opponent, is a win/win situation. Not a compromise.

As I explained, it is very easy to switch this feature off. But you should
be prepared for significant loss of strength if you do that.