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A Material Base for everybody
A material imbalance table as first introduced by Vasik Rajlich in Rybka 1.0 beta now made easy to implement using Protools menu F10. It's data structure first:
static int mat_bonus [9][9] [3][3] [3][3] [3][3] [2][2]; // wp|bp|wn|bn|wb|bb|wr|br|wq|bq
static int mat_pos [9][9] [3][3] [3][3] [3][3] [2][2];
static int mat_perc [9][9] [3][3] [3][3] [3][3] [2][2];
Step-1
- Copy a good quality and large PGN database into the PGN subfolder.
- Select the PGN with Load PGN and press Make Matbase.
- OPTIONS:
Bishop color - Irrelevant for the moment.
Score Factor - Only relevant if you want to use the precalculated scores.
Minimum ELO - Extremely important. Consider only games where both players have a
given minimum elo rating.
The utility will create the following *.mat output files with the above listed data structure
| bonus.mat |
Contains the precalculated bonus for each cell multiplied with the Score Factor percentage. |
| pos.mat |
Contains the number of positions for each cell. |
| perc.mat |
Contains the winning percentage for each cell. |
Step-2
Insert the 3 files at program start into the 3 tables. The code:
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int wp,wn,wb,wr,wq,bp,bn,bb,br,bq;
fp1 = fopen("bonus.mat","rb");
fp2 = fopen("pos.mat","rb");
fp3 = fopen("perc.mat","rb");
for (wp=0; wp<=8; wp++)
for (bp=0; bp<=8; bp++)
for (wn=0; wn<=2; wn++)
for (bn=0; bn<=2; bn++)
for (wb=0; wb<=2; wb++)
for (bb=0; bb<=2; bb++)
for (wr=0; wr<=2; wr++)
for (br=0; br<=2; br++)
for (wq=0; wq<=1; wq++)
for (bq=0; bq<=1; bq++)
{ fread(&mat_bonus [wp][bp] [wn][bn] [wb][bb] [wr][br] [wq][bq],4,1,fp1);
fread(&mat_pos [wp][bp] [wn][bn] [wb][bb] [wr][br] [wq][bq],4,1,fp2);
fread(&mat_perc [wp][bp] [wn][bn] [wb][bb] [wr][br] [wq][bq],4,1,fp3); }
fclose(fp1); fclose(fp2); fclose(fp3);
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Step-3
Then finally in EVAL add the below code:
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void Material_Imbalance()
{ int wp,wn,wb,wr,wq,bp,bn,bb,br,bq;
wp = number_of_white_pawns;
wn = number_of_white_knights; // max=2
wb = number_of_white_bishops; // max=2
wr = number_of_white_rooks; // max=2
wq = number_of_white_queens; // max=1
bp = number_of_black_pawns;
bn = number_of_black_knights; // max=2
bb = number_of_black_bishops; // max=2
br = number_of_black_rooks; // max=2
bq = number_of_black_queens; // max=1
/////////////////////////////////////////////////////////////////////////////////////////////////
/// Get the precalculated bonus from the cell and add it to your EVAL variable ///
/// NOTE: the precalculated bonus is from the white point of view. ///
/////////////////////////////////////////////////////////////////////////////////////////////////
your_eval_score += mat_bonus [wp][bp] [wn][bn] [wb][bb] [wr][br] [wq][bq])
return; // That's it !
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/// Another and more preferable way is to calculate the bonus yourself ///
/// via the number of positions in the cell and its percentage. ///
/// For instance multiply your EVAL with the percentage of the cell: ///
/// In case your eval score is 100 and the cell reports a 85% score the new score will be 135 ///
/// In case your eval score is 100 and the cell reports a 20% score the new score will be 70 ///
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////
if (mat_pos [wp][bp] [wn][bn] [wb][bb] [wr][br] [wq][bq] < 10) return; // too few positions !
x=mat_perc [wp][bp] [wn][bn] [wb][bb] [wr][br] [wq][bq];
your_eval_score += (your_eval_score * (x-50))/100;
return;
}
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Final comments
A big advantage of the system is that you can replace the material base any time by selecting a different PGN.
Using a comp-comp PGN is preferable, just collect games of the current top-engines and you are pretty safe. The quality of the Material Base is in the quality of the PGN.
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