src/eval.h

   1 /* Copyright (C) 2007-2011 Vincent Ollivier
   2  *
   3  * Purple Haze is free software: you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation, either version 3 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * Purple Haze is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  15  */
  16
  17 #ifndef EVAL_H
  18 #define EVAL_H
  19
  20 #include "common.h"
  21
  22 // Specific bonus and malus
  23 static const int CASTLE_BONUS          = 100;
  24 static const int BISHOP_PAIR_BONUS     =  40;
  25 static const int OPEN_FILE_BONUS       =  30;
  26 static const int HALF_OPEN_FILE_BONUS  =  15;
  27 static const int REDUNDANCY_MALUS      = -10;
  28 static const int BREAKING_CASTLE_MALUS = -40;
  29 static const int NO_PAWNS_MALUS        = -50;
  30
  31 static const int PIECE_VALUE[] = {
  32         0, // Empty piece
  33       100, // Pawn
  34       325, // Knight
  35       325, // Bishop
  36       500, // Rook
  37       965, // Queen (Rook + Minor + Pawn + Bishop Pair)
  38     10000, // King
  39 };
  40
  41 // Pieces values adjustments based on the number of pawns
  42 static const int PAWNS_ADJUSTEMENT[][9] = {
  43     {   0,   0,   0,   0,   0,   0,   0,   0,   0 }, // Empty
  44     {   0,   0,   0,   0,   0,   0,   0,   0,   0 }, // Pawns
  45     { -30, -24, -18, -12,  -6,   0,   6,  12,  18 }, // Knights
  46     { -15, -12,  -9,  -6,  -3,   0,   3,   6,   9 }, // Bishops
  47     {  60,  48,  36,  24,  12,   0, -12, -24, -36 }, // Rooks
  48     {  30,  24,  18,  12,   6,   0,   0,   0,   0 }, // Queens
  49     {   0,   0,   0,   0,   0,   0,   0,   0,   0 }  // King
  50 };
  51
  52 static const int MULTI_PAWNS_MALUS[] = { // Pawns on the same file
  53     0,   -5,  -50,  -75, -100, -100, -100
  54 };
  55
  56 // Game phase used in tapered evaluation
  57 enum Phase : unsigned char { OPENING, ENDING };
  58 static const Phase PHASES[] = { OPENING, ENDING };
  59
  60 // Coefficient of each type of piece to determine the game phase
  61 static const int PHASE_COEF[] = { 0, 1, 2, 2, 4, 8, 0 };
  62
  63 // Opening number
  64 static const int PHASE_MAX = 16 * PHASE_COEF[PAWN] +
  65                               4 * PHASE_COEF[KNIGHT] +
  66                               4 * PHASE_COEF[BISHOP] +
  67                               4 * PHASE_COEF[ROOK] +
  68                               2 * PHASE_COEF[QUEEN]; // == 64
  69
  70 // PST parameters
  71 static const int BORDER_MALUS = -5;
  72 static const int CENTER_BONUS[] = {
  73     0,   0,   1,   2,   2,   1,   0,   0
  74 };
  75 static const int PAWN_FILES_VALUES[] = {
  76     -15,  -5,   1,   5,   5,   1,  -5, -15
  77 };
  78 static const int OPENING_RANKS_BONUS[][8] = {
  79     {  0,   0,   0,   0,   0,   0,   0,   0 }, // Dummy for PieceType EMPTY
  80     {  0, -10,  -5,   5,   4,   3,   0,   0 }, // Pawns
  81     {  0,   1,   2,   4,   4,   2,   0,   0 }, // Knights
  82     {  0,   1,   2,   3,   3,   2,   0,   0 }, // Bishops
  83     { 30,   0,   0,   0,   0,   0,   0,   0 }, // Rooks
  84     { -5,   1,   2,   3,   3,   2,   1,   0 }, // Queens
  85     {  0, -15, -40, -40, -40, -40, -40, -40,}  // King
  86 };
  87
  88 inline static bool has_bishop_pair(const Color c, const Pieces &pieces)
  89 {
  90     assert(pieces.count(c, BISHOP) == 2);
  91     const Square fb = pieces.position(c, BISHOP, 0);
  92     const Square sb = pieces.position(c, BISHOP, 1);
  93     return !Board::is_same_color(fb, sb);
  94 }
  95
  96 #endif /* !EVAL_H */