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Subject: Re: Recapture extension questions and a post that Ed missed

Author: Uri Blass

Date: 11:04:16 01/04/03

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On January 04, 2003 at 12:21:38, Ed Schröder wrote:

<snipped>
>Why do it in make_move and undo_move?
>
>As said, do it at the very beginning of a new ply, something like this:
>
>  current_depth++;                      // going one ply deeper in the tree
>  i_score=i_score+table[current_depth]; -> update i_score here
>  Generate_Moves();
>  Get_a_move_till_all_moves_are_done

1)Maybe we do not talk in the same language.
I will try to explain myself(I decided to add numbers to my comments to do some
order in this post(I have 6 comments).

makemove and Generate_moves are different functions for me.
Generate_Moves generate all the legal moves and make_move only makes one move.
I do nodes++ only when I make moves.

The beginning of a new ply is exactly after make move so I do not see what is
the difference between doing it in the beginning of a new ply and doing it after
makemove.

<snipped>
>>>>b)What do you mean by I_score
>>>>Is is the score after the recapture or before the recapture.
>
>
>>>I_SCORE is material value (plus PS values) of the current board position.
>>
>>Yes but it is not clear for me if the current board position is before the
>>recapture or after the recapture.
>
>Read again, i_score represents the current board position. So before the
>recapture in make_move it will be something like -300 and after make_move
>something like 0.00

2)I understand it but this was not the question.

The question was about the value of I_score that you use in your formula if to
extend recaptures and the answer was that you used the 0.00 and not the -300(or
-3 or +3 see later).



<snipped>
>>The question is if piece_value after the captures
>>BxN PxB is the value of the bishop or the value of the knight.
>
>What do you mean with piece_value? Do you mean i_score?

3)I mean to the same thing that you mean.

This is copied from your page:
if (I_SCORE > HIGH + piece value depth-1)     -> do not extend
  else: extend tree with one ply.



<snipped>
>>The question is if it is from the point of view of the side to move.
>>
>>I always use it from the point view of the side to move but I have doubts if
>>it is done in that way in Rebel after I did not understand another subject
>>about pruning in the qsearch when for me the logical way is to prune when
>>score <alpha-something and for you it is >beta+something.
>
>1.e4     i_score = 0.10
>1..e5    i_score = 0.00
>2.Nf3    i_score = 0.12
>2..Nc6   i_score = -0.05
>3.Bb5    i_score = 0.20
>3..a6    i_score = -0.18
>4.Bxc6   i_score = 3.30

4)+3.30 or -3.30

Here are previous words of you in this post.
"Read again, i_score represents the current board position. So before the
recapture in make_move it will be something like -300 and after make_move
something like 0.00"

I do not understand if I_score is from the point of view of the side to move
or not.

>4..dxc6  i_score = -0.25
>
>or something like that.

5)You have
if (I_SCORE > HIGH + piece value depth-1)     -> do not extend
  else: extend tree with one ply.

It is clear that you extend but I am not sure about the numbers of the last
condition.

If I translate it to numbers do I get the consition
-0.25>2.25+bishop_value-1?

I think that using this example and giving the numbers of all the varaibles may
be productive for understanding.

>
>Good luck.
>
>Ed

6)Good Luck in explaining it better

Uri



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