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Subject: Re: Starting position to 30 ply

Author: Mike S.

Date: 02:17:26 06/04/01

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On June 04, 2001 at 04:57:40, Uri Blass wrote:

>On June 04, 2001 at 04:35:19, Uri Blass wrote:
>
>>On June 04, 2001 at 03:36:25, Rudolf Huber wrote:
>>
>>>A couple of days ago I said (in a discussion about mtd(f)) that my chess
>>>program can search the starting position to 30 ply over night when the eval
>>>evaluates material only:
>>>
>>>SOS no eval
>>>  1.00   0:00    0.00   1.h3 (2)
>>>  2.00   0:00    0.00   1.h3 (45)
>>>  3.00   0:00    0.00   1.h3 h6 2.h4 (138)
>>>  (...)

>>(...)
>>3)I see that you get depth 1 with only 2 nodes
>>(...)
>>4)How do you get 45 nodes at depth 2?
>>(...)

>I guess 2 nodes at depth 1 is because you first use the qsearch to see that
>there is no captures and after it generates one node and evaluates it(it is
>obvious that all the other will be the same)
>
>If we use the same principle at depth 2 I get:
>1)21 obvious nodes that are root position and positions after one ply.
>2)There are no captures after the main line h3 so it is enough to generate one
>move to get 1.h3 h6 and get evaluation 0.00
>3)I need to search for a killer move for every other move that is not 1.h3
>so I get 19 lines 1.h4 h6,1.g3 h6,1.g4 h6....
>4)There are captures after some of the lines(I mean d3 h6 and d4 h6 so you need
>to search 1.d3 h6 2.Bxh6 Rxh6
>1.d4 h6 Bxh6 Rxh6 so you get more 4 nodes.
>Total number of nodes seem to be 21+1+19+4=45
>
>I needed a time to see 4 and this is the reason that I did not understand 45 in
>a short time.

But it was a short time compared to what i.e. I would have needed (if I would
even have understood that this was an interesting question looking at that data,
from ply 1...3).

I want to express that I am quite impressed by this analytical and sharp-witted
way of looking at these results Uri has shown. It may look easy after we have
read his explanation :o), but it wasn't.

The CCC is really a perfect place for computer chess; I can't think of a better
example to prove this.

Thanks,
M.Scheidl



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