Use a polynomial weighted evaluation to calculate
material value.
This is far more flexible and elegant then applying
a series of single euristic rules as before.
Also correct a design issue in which we returned two
values, one for middle game and one for endgame, while
instead, because game phase is a function of board
material itself, only one value should be calculated and
used both for mid and end game.
Verified it is equivalent to the tuning branch results with
parameter values sampled after 40.000 games.
After 999 games at 1+0
Mod vs Orig +277 =482 -240 51.85% 518.0/999 +13 ELO
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Note that some pawns and material info has been switched
to int from int8_t.
This is a waste of space but it is not clear if we have a
faster or slower code (or nothing changed), some test should be
needed.
Few warnings still are alive.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Also integrate scaling and evaluation in a
single base class.
Nice use of templates here :-)
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Is a new evaluation rule that gives bonus in midgame
to the side that has more space behind pawns for its
minor pieces.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
