Author: Harald Lüßen
Date: 11:43:28 02/22/04
Go up one level in this thread
On February 21, 2004 at 22:05:52, Jaime Benito de Valle Ruiz wrote:
>Hi,
>
>I'm sure we can all improve lots of things here.
>However, I'd like to point out something: Most engines give a score between
>-2.00 and -4.00 more or less, in a position where the side to move (black) is
>hopelessfuly lost. Your engine gives a high positive score for white (if I
>understood, the side to move). This, in my opinion, is the reason for we
>started this experiment: To find flaws.
Sorry, I was confused with the value for side to move and value for white.
Therefore I did some signs wrong. I misinterpreted my own engine logfile.
I think the computation of my engine was correct with respect to this problem.
The hopefully correct values of 'Elephant' are:
-3.88
2.20
1.69
-2.38
3.44
-7.16
-1.41
0.84
1.45
-5.19
-0.47
-1.89
-6.58
-0.58
5.88
-0.88
1.69
1.73
0.92
1.15
-0.87
-3.04
0.36
1.33
1.88
0.42
0.16
-4.14
This could also be seen in the second part of my former posting.
The eval= scores are from the side to move and now I understand
why this is the default for this evaluation collection.
As a bonus information I tell you how the first score -3.88 was found.
The terms are mostly ad hoc values and are not balanced. Perhaps there
are more flaws and bad scalings.
"KS-00001"
+---+---+---+---+---+---+---+---+
8 |*r | | |*k | |*b | |*r | Black to move
+---+---+---+---+---+---+---+---+
7 | | |*p | | |*p |*p |*p |
+---+---+---+---+---+---+---+---+
6 |*p | | | |*q | | | |
+---+---+---+---+---+---+---+---+
5 | | | P |*p | N | | | |
+---+---+---+---+---+---+---+---+
4 | Q | | | P |*n | | | |
+---+---+---+---+---+---+---+---+
3 | | | | | B | | | |
+---+---+---+---+---+---+---+---+
2 | P | P | | | | P | P | P |
+---+---+---+---+---+---+---+---+
1 | | R | | | R | | K | |
+---+---+---+---+---+---+---+---+
a b c d e f g h
The following values in centipawns are seen from white.
(I hate this +-+-+-thinking ;-)
--> material score = 100 (1 pawn)
White has all pieces developed and castled
Black has 3 pieces developed and cannot castle
We are in early middlegame
White pawns
supporting pawns +18
position +91
advanced +24
Black pawns
isolated +12
supporting pawns -9
position -72
White king
position +28
pawn shield +45
Black king
position +9
pawn shield -15
--> pawns and kings = 131 (saved in the pawn & king hash table)
Black cannot castle +35
White queen
king tropism -12
Black queen
adventure in black opening +60
White knight
position +25
king tropism -6
Black knight
position -25
king tropism +8
White bishops
blocked by pawns -2
Black bishops
blocked by pawns +2
White rooks
on open line near black king +30
on center lines +4
on (half) open lines +30
king tropism -6
Black rooks
king tropism +14
--> piece positional value = 157
==> positional value = 131 + 157 = 288
==> evaluation = 388 for white or -388 for black (side to move)
Harald
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