Questions to positional detail evaluation

[Tord Romstad]

Which is equivalent to saying the advantage of having the move (in the opening position) is 1/3 pawn. In Bruja, I throw in a small plus for the side moving since I figure it must be worth something. But there is no intelligence in what I do. Does anyone have a better way of evaluating the worth of having the move?

I currently don't have any bonus for the side to move, although I have often thought about trying it. Perhaps it would be better to let the size of the bonus depend on the pawn centre? I guess that having the move is usually more important in open positions than in very closed positions. King safety may also be worth considering. For instance, if both sides have very bad king safety, having the move is more likely to be very important.

When choosing the size of the bonus, it could be interesting to run experiments. Choose a big number of quiescent positions, and search all positions to a fixed depth. Then change the side to move in all positions, and search all positions again to the same depth. The differences in scores should give you a reasonable value for the side to move bonus.

Tord

[fierz]

Hi Fierz,

indeed those values seem to be absurd. Thus I am wondering, that it needed so long until a comment like yours would come.

I am testing a local evaluation function WITHOUT any chess knowledge integrated by the programmer. It is not the result after a deep positonal search, only after a QSearch. If you would be able to write an evaluation function giving a correct sequence without any search, you would be the king of all programmers.

The test is mainly to estimate the evaluation speed.

Reinhard.

P.S.: moreover, my actual values are:

Code: Select all

FEN: rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1

  +-*--b--c--d--*--f--g--*-+ MS Vis. Studio C++ Vers. 13.10
8 |[r][n][b][q][k][b][n][r]| (Compilation: Nov  8 2004)
7 |[p][p][p][p][p][p][p][p]| Testscenario QSearch(-max, +max):
6 |   :::   :::   :::   :::| (With TT Caching 384.0 MB / 4-fold)
5 |:::   :::   :::   :::   | TT Accesses 26960, Success 0.0%
4 |   :::   :::   :::   :::|
3 |:::   :::   :::   :::   | Smirf Test No.:         29
2 |<P><P><P><P><P><P><P><P>| Evaluated Trees Count:  20*1348
1 |<R><N><B><Q><K><B><N><R>| TT Accesses per Second: 107840
=>+-*--b--c--d--*--f--g--*-+ Time:                   0.250 sec

  0.164 e2-e4    0.164 e2-e3    0.148 d2-d4    0.125 Ng1-f3   0.121 d2-d3
  0.117 Nb1-c3  -0.039 c2-c4   -0.039 c2-c3   -0.066 f2-f4   -0.066 f2-f3
 -0.117 h2-h4   -0.117 a2-a4   -0.117 Nb1-a3  -0.145 Ng1-h3  -0.148 b2-b4
 -0.148 g2-g4   -0.148 g2-g3   -0.148 b2-b3   -0.164 h2-h3   -0.164 a2-a3

hi reinhard,

now i understand even less
what is the difference between these values, and the ones in the last post? to my mind, it is irrelevant whether you take a static score after each of the first 20 moves, or whether you add a Qsearch behind it, or whether you do a shallow or a deep search. in all of these cases your evaluation for a move like d3 should be lower than for d4, and in all of these cases the value for f3? should be lower than for c4.

what am i missing?

also, i am curious about this part:

I am testing a local evaluation function WITHOUT any chess knowledge integrated by the programmer.

what are you doing then? is smirf already playing chess? if yes, how well?

cheers
martin

[Reinhard Scharnagl]

Hi Fierz,

what are you doing then? is smirf already playing chess? if yes, how well?

yes, since some days it is playing weak chess on 8x8 and 10x8 boards. I am about to design a better dynamic search. I just wanted to have a playing program first.

in all of these cases your evaluation for a move like d3 should be lower than for d4, and in all of these cases the value for f3? should be lower than for c4.

I think that this is the case that moment.

Regards, Reinhard.