Author: Vincent Diepeveen
Date: 13:53:28 04/27/01
Go up one level in this thread
On April 27, 2001 at 08:50:51, Robert Hyatt wrote:
>On April 26, 2001 at 23:36:55, Albert Silver wrote:
>
>>On April 26, 2001 at 22:52:20, Robert Hyatt wrote:
>>
>>>On April 26, 2001 at 20:29:07, Uri Blass wrote:
>>>
>>>>On April 26, 2001 at 20:06:38, Robert Hyatt wrote:
>>>>
>>>>>On April 26, 2001 at 17:30:11, Uri Blass wrote:
>>>>>
>>>>>>On April 26, 2001 at 17:24:09, Robert Hyatt wrote:
>>>>>>
>>>>>>>On April 26, 2001 at 16:57:53, Christophe Theron wrote:
>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>If it is just that, then there are ways to avoid these problems. Expensive, but
>>>>>>>>less expensive than brute force.
>>>>>>>>
>>>>>>>>The problem I abhor is when my program gets oursearched. This by far outweigths
>>>>>>>>any other minor problem. Brute force always has this problem, not just in one
>>>>>>>>game out of 1000.
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> Christophe
>>>>>>>
>>>>>>>
>>>>>>>Maybe that was Hsu's point. At 200M nodes per second you probably won't
>>>>>>>get outsearched if you search every node twice. :)
>>>>>>
>>>>>>Hsu is wrong.
>>>>>>
>>>>>>Deeper blue made a tactical mistake in the second game against kasparov because
>>>>>>it did not search deep enough.
>>>>>>
>>>>>>It did not see that the final position is drawn and it proves that search is
>>>>>>important also at 200M nodes per second.
>>>>>>
>>>>>>Uri
>>>>>
>>>>>
>>>>>By that definition every lost game makes a tactical mistake.
>>>>
>>>>The point is that it is not a mistake because of a zunzwang so recursive null
>>>>move could help to find the right move faster.
>>>>
>>>>Deeper blue
>>>> Since _nobody_
>>>>>has shown a draw in that position with a computer, I can personally forgive
>>>>>deep blue as well.
>>>>
>>>>I remember that Diep could see enough in order to play 44.Kh1 and not 44.Kf1 in
>>>>the position some plies before the drawn position.
>>>>
>>>>I guess that other programs can also do the same if you give them enough time.
>>>>
>>>>Here is the relevant position
>>>>[D]R7/1r3kp1/1qQb1p1p/1p1PpP2/1Pp1B3/2P4P/6P1/6K1 w - - 0 1
>>>>
>>>>Deeper blue searched 192 seconds and played 44.Kf1
>>>>I am interested to know what programs can see after 192*200,000,000 nodes.
>>>>
>>>>Uri
>>>
>>>
>>>Here is crafty's output on my notebook. Lots of mind changing...
>>>
>>>I will guarantee you that if a program plays Kh1 over Kf1 it is
>>>_not_ because it is avoiding a draw. They are not going to see that
>>>from here...
>>>
>>>The following is the best 4 moves and scores, searched for
>>>60 seconds. NOthing marks the first 2 as being much different.
>>>the third is close...
>>>
>>> ({14:+1.85} 1. Kf1 Rb8 2. Ra6 Qxc6 3. dxc6 Kf8 4. Ra7 Rc8 5. Rb
>>>7 h5 6. Rxb5 Ke7 7. Ra5 Rc7 8. Ke2 h4 $18)
>>> ({14:+1.88} 1. Kh2 Rb8 2. Ra6 Qxc6 3. dxc6 Kf8 4. Ra7 Rd8 5. Rb
>>>7 Rc8 6. Rxb5 $18)
>>> ({14:+1.54} 1. Kh1 Rb8 2. Ra6 Qxc6 3. dxc6 Kf8 4. Ra7 Rc8 5. Rb
>>>7 Ra8 6. Rxb5 Ra1+ 7. Kh2 Re1 8. Rd5 Bxb4 9. cxb4 Rxe4 $18)
>>> ({14:+0.39} 1. Qxb6 Rxb6 2. Ra7+ Kf8 3. Kf1 Bb8 4. Rd7 Bd6 5. K
>>>e2 Be7 6. Ra7 Bd6 7. h4 Rb8 $14)
>>>
>>>
>>>I don't want to even talk about Diep or any other program playing Kh1 or
>>>not playing Kf1 until I see real PVs and scores to prove they know that Kf1
>>>leads to a draw...
>>
>>Frankly, I don't even understand why this topic keeps coming up still. I already
>>showed Vincent, and others who saw the posts, that there were many lines that
>>the program considered a draw only because it hadn't seen certain potential
>>threats, and only AFTER it had seen how to counter those threats could one say
>>the program saw a draw. Otherwise it is merely a horizon effect. It sees a draw,
>>because it _hasn't_ seen the potential to complicate. When it does, the eval
>>will swing again, until it has neautralized those attempts, after which one can
>>safely say the program sees a draw. So if Diep announces it's a draw nice and
>>early, one can safely say it is a horizon effect, nothing more.
>>
>> Albert
>
>
>Too many folks, some program authors included, don't understand how a draw
>score gets propagated back up the tree. Which makes them assume that when a
>program says "draw" then the draw is absolutely forced. This is completely
I never got a 0.00 score. I get a near to 0.00 score, so a positional
draw and it is *not* a horizon effect.
DIEP's evaluation is biggest of the world. So obviously i have things inside
it which others do not have and probably never will.
>false. A program will propagate the draw score backward when it thinks one
>side is ahead and the other side can force a repetition. But it may well find
>later that the side it thought was ahead was not. And the draw score becomes
>invalid.
>
>The only absolutely correct scores we generate are mate in N.
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