Author: Uri Blass
Date: 22:31:39 04/26/01
Go up one level in this thread
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.
If the score is only slightly above 0.00 then it probably saw something
important.
I did not see the score of Deep blue gets down.
Programs may lose after the right line that Deeper blue did not consider as best
but I believe that if they search deep enough to see the loss in the line of
Qd6-d7-c6 then they also search deep enough to see how to avoid the loss.
Uri
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