Use stockfish piece-square tables

gen.js

···
+const tables = {
+  "pawn": `#(
+  #(000, 000, 000, 000, 000, 000, 000, 000),
+  #(-007, 007, -003, -013, 005, -016, 010, -008),
+  #(005, -012, -007, 022, -008, -005, -015, -008),
+  #(013, 000, -013, 001, 011, -002, -013, 005),
+  #(-004, -023, 006, 020, 040, 017, 004, -008),
+  #(-009, -015, 011, 015, 032, 022, 005, -022),
+  #(003, 003, 010, 019, 016, 019, 007, -005),
+  #(000, 000, 000, 000, 000, 000, 000, 000),
+)`,
+
+  "knight": `#(
+  #(-201, -083, -056, -026, -026, -056, -083, -201),
+  #(-067, -027, 004, 037, 037, 004, -027, -067),
+  #(-009, 022, 058, 053, 053, 058, 022, -009),
+  #(-034, 013, 044, 051, 051, 044, 013, -034),
+  #(-035, 008, 040, 049, 049, 040, 008, -035),
+  #(-061, -017, 006, 012, 012, 006, -017, -061),
+  #(-077, -041, -027, -015, -015, -027, -041, -077),
+  #(-175, -092, -074, -073, -073, -074, -092, -175),
+)`,
+
+  "bishop": `#(
+  #(-048, 001, -014, -023, -023, -014, 001, -048),
+  #(-017, -014, 005, 000, 000, 005, -014, -017),
+  #(-016, 006, 001, 011, 011, 001, 006, -016),
+  #(-012, 029, 022, 031, 031, 022, 029, -012),
+  #(-005, 011, 025, 039, 039, 025, 011, -005),
+  #(-007, 021, -005, 017, 017, -005, 021, -007),
+  #(-015, 008, 019, 004, 004, 019, 008, -015),
+  #(-053, -005, -008, -023, -023, -008, -005, -053),
+)`,
+
+  "rook": `#(
+  #(-017, -019, -001, 009, 009, -001, -019, -017),
+  #(-002, 012, 016, 018, 018, 016, 012, -002),
+  #(-022, -002, 006, 012, 012, 006, -002, -022),
+  #(-027, -015, -004, 003, 003, -004, -015, -027),
+  #(-013, -005, -004, -006, -006, -004, -005, -013),
+  #(-025, -011, -001, 003, 003, -001, -011, -025),
+  #(-021, -013, -008, 006, 006, -008, -013, -021),
+  #(-031, -020, -014, -005, -005, -014, -020, -031),
+)`,
+
+  "queen": `#(
+  #(-002, -002, 001, -002, -002, 001, -002, -002),
+  #(-005, 006, 010, 008, 008, 010, 006, -005),
+  #(-004, 010, 006, 008, 008, 006, 010, -004),
+  #(000, 014, 012, 005, 005, 012, 014, 000),
+  #(004, 005, 009, 008, 008, 009, 005, 004),
+  #(-003, 006, 013, 007, 007, 013, 006, -003),
+  #(-003, 005, 008, 012, 012, 008, 005, -003),
+  #(003, -005, -005, 004, 004, -005, -005, 003),
+)`,
+
+  "king": `#(
+  #(059, 089, 045, -001, -001, 045, 089, 059),
+  #(088, 120, 065, 033, 033, 065, 120, 088),
+  #(123, 145, 081, 031, 031, 081, 145, 123),
+  #(154, 179, 105, 070, 070, 105, 179, 154),
+  #(164, 190, 138, 098, 098, 138, 190, 164),
+  #(195, 258, 169, 120, 120, 169, 258, 195),
+  #(278, 303, 234, 179, 179, 234, 303, 278),
+  #(271, 327, 271, 198, 198, 271, 327, 271),
+)`,
+
+  "pawn_endgame": `#(
+  #(000, 000, 000, 000, 000, 000, 000, 000),
+  #(000, -011, 012, 021, 025, 019, 004, 007),
+  #(028, 020, 021, 028, 030, 007, 006, 013),
+  #(010, 005, 004, -005, -005, -005, 014, 009),
+  #(006, -002, -008, -004, -013, -012, -010, -009),
+  #(-010, -010, -010, 004, 004, 003, -006, -004),
+  #(-010, -006, 010, 000, 014, 007, -005, -019),
+  #(000, 000, 000, 000, 000, 000, 000, 000),
+)`,
+
+  "knight_endgame": `#(
+  #(-100, -088, -056, -017, -017, -056, -088, -100),
+  #(-069, -050, -051, 012, 012, -051, -050, -069),
+  #(-051, -044, -016, 017, 017, -016, -044, -051),
+  #(-045, -016, 009, 039, 039, 009, -016, -045),
+  #(-035, -002, 013, 028, 028, 013, -002, -035),
+  #(-040, -027, -008, 029, 029, -008, -027, -040),
+  #(-067, -054, -018, 008, 008, -018, -054, -067),
+  #(-096, -065, -049, -021, -021, -049, -065, -096),
+)`,
+
+  "bishop_endgame": `#(
+  #(-046, -042, -037, -024, -024, -037, -042, -046),
+  #(-031, -020, -001, 001, 001, -001, -020, -031),
+  #(-030, 006, 004, 006, 006, 004, 006, -030),
+  #(-017, -001, -014, 015, 015, -014, -001, -017),
+  #(-020, -006, 000, 017, 017, 000, -006, -020),
+  #(-016, -001, -002, 010, 010, -002, -001, -016),
+  #(-037, -013, -017, 001, 001, -017, -013, -037),
+  #(-057, -030, -037, -012, -012, -037, -030, -057),
+)`,
+
+  "rook_endgame": `#(
+  #(018, 000, 019, 013, 013, 019, 000, 018),
+  #(004, 005, 020, -005, -005, 020, 005, 004),
+  #(006, 001, -007, 010, 010, -007, 001, 006),
+  #(-005, 008, 007, -006, -006, 007, 008, -005),
+  #(-006, 001, -009, 007, 007, -009, 001, -006),
+  #(006, -008, -002, -006, -006, -002, -008, 006),
+  #(-012, -009, -001, -002, -002, -001, -009, -012),
+  #(-009, -013, -010, -009, -009, -010, -013, -009),
+)`,
+
+  "queen_endgame": `#(
+  #(-075, -052, -043, -036, -036, -043, -052, -075),
+  #(-050, -027, -024, -008, -008, -024, -027, -050),
+  #(-038, -018, -012, 001, 001, -012, -018, -038),
+  #(-029, -006, 009, 021, 021, 009, -006, -029),
+  #(-023, -003, 013, 024, 024, 013, -003, -023),
+  #(-039, -018, -009, 003, 003, -009, -018, -039),
+  #(-055, -031, -022, -004, -004, -022, -031, -055),
+  #(-069, -057, -047, -026, -026, -047, -057, -069),
+)`,
+
+  "king_endgame": `#(
+  #(011, 059, 073, 078, 078, 073, 059, 011),
+  #(047, 121, 116, 131, 131, 116, 121, 047),
+  #(092, 172, 184, 191, 191, 184, 172, 092),
+  #(096, 166, 199, 199, 199, 199, 166, 096),
+  #(103, 156, 172, 172, 172, 172, 156, 103),
+  #(088, 130, 169, 175, 175, 169, 130, 088),
+  #(053, 100, 133, 135, 135, 133, 100, 053),
+  #(001, 045, 085, 076, 076, 085, 045, 001),
+)`,
+}
+
+let out = "";
+
+for (let [name, table] of Object.entries(tables)) {
+  if (!table.startsWith("#(\n")) throw undefined;
+  if (!table.endsWith("\n)")) throw undefined;
+
+  table = table.slice(3, table.length - 2);
+
+  const rows = table.split("\n").reverse();
+
+  const reverseTable = `#(
+${rows.join("\n")}
+)`;
+
+  out += `const ${name} = ${reverseTable}\n\n`;
+}
+
+console.log(out);

src/starfish/internal/piece_table.gleam

···
 // need to worry about the cost of updating.
 
 const pawn = #(
-  #(0, 0, 0, 0, 0, 0, 0, 0),
-  #(30, 30, 30, 30, 30, 30, 30, 30),
-  #(10, 10, 20, 30, 30, 20, 10, 10),
-  #(5, 5, 10, 25, 25, 10, 5, 5),
-  #(0, 0, 0, 20, 20, 0, 0, 0),
-  #(5, -5, -10, 0, 0, -10, -5, 5),
-  #(5, 10, 10, -20, -20, 10, 10, 5),
-  #(0, 0, 0, 0, 0, 0, 0, 0),
+  #(000, 000, 000, 000, 000, 000, 000, 000),
+  #(003, 003, 010, 019, 016, 019, 007, -005),
+  #(-009, -015, 011, 015, 032, 022, 005, -022),
+  #(-004, -023, 006, 020, 040, 017, 004, -008),
+  #(013, 000, -013, 001, 011, -002, -013, 005),
+  #(005, -012, -007, 022, -008, -005, -015, -008),
+  #(-007, 007, -003, -013, 005, -016, 010, -008),
+  #(000, 000, 000, 000, 000, 000, 000, 000),
 )
 
 const knight = #(
-  #(-50, -40, -30, -30, -30, -30, -40, -50),
-  #(-40, -20, 0, 0, 0, 0, -20, -40),
-  #(-30, 0, 10, 15, 15, 10, 0, -30),
-  #(-30, 5, 15, 20, 20, 15, 5, -30),
-  #(-30, 0, 15, 20, 20, 15, 0, -30),
-  #(-30, 5, 10, 15, 15, 10, 5, -30),
-  #(-40, -20, 0, 5, 5, 0, -20, -40),
-  #(-50, -40, -30, -30, -30, -30, -40, -50),
+  #(-175, -092, -074, -073, -073, -074, -092, -175),
+  #(-077, -041, -027, -015, -015, -027, -041, -077),
+  #(-061, -017, 006, 012, 012, 006, -017, -061),
+  #(-035, 008, 040, 049, 049, 040, 008, -035),
+  #(-034, 013, 044, 051, 051, 044, 013, -034),
+  #(-009, 022, 058, 053, 053, 058, 022, -009),
+  #(-067, -027, 004, 037, 037, 004, -027, -067),
+  #(-201, -083, -056, -026, -026, -056, -083, -201),
 )
 
 const bishop = #(
-  #(-20, -10, -10, -10, -10, -10, -10, -20),
-  #(-10, 0, 0, 0, 0, 0, 0, -10),
-  #(-10, 0, 5, 10, 10, 5, 0, -10),
-  #(-10, 5, 5, 10, 10, 5, 5, -10),
-  #(-10, 0, 10, 10, 10, 10, 0, -10),
-  #(-10, 10, 10, 10, 10, 10, 10, -10),
-  #(-10, 5, 0, 0, 0, 0, 5, -10),
-  #(-20, -10, -10, -10, -10, -10, -10, -20),
+  #(-053, -005, -008, -023, -023, -008, -005, -053),
+  #(-015, 008, 019, 004, 004, 019, 008, -015),
+  #(-007, 021, -005, 017, 017, -005, 021, -007),
+  #(-005, 011, 025, 039, 039, 025, 011, -005),
+  #(-012, 029, 022, 031, 031, 022, 029, -012),
+  #(-016, 006, 001, 011, 011, 001, 006, -016),
+  #(-017, -014, 005, 000, 000, 005, -014, -017),
+  #(-048, 001, -014, -023, -023, -014, 001, -048),
 )
 
 const rook = #(
-  #(0, 0, 0, 0, 0, 0, 0, 0),
-  #(5, 10, 10, 10, 10, 10, 10, 5),
-  #(-5, 0, 0, 0, 0, 0, 0, -5),
-  #(-5, 0, 0, 0, 0, 0, 0, -5),
-  #(-5, 0, 0, 0, 0, 0, 0, -5),
-  #(-5, 0, 0, 0, 0, 0, 0, -5),
-  #(-5, 0, 0, 0, 0, 0, 0, -5),
-  #(0, 0, 0, 5, 5, 0, 0, 0),
+  #(-031, -020, -014, -005, -005, -014, -020, -031),
+  #(-021, -013, -008, 006, 006, -008, -013, -021),
+  #(-025, -011, -001, 003, 003, -001, -011, -025),
+  #(-013, -005, -004, -006, -006, -004, -005, -013),
+  #(-027, -015, -004, 003, 003, -004, -015, -027),
+  #(-022, -002, 006, 012, 012, 006, -002, -022),
+  #(-002, 012, 016, 018, 018, 016, 012, -002),
+  #(-017, -019, -001, 009, 009, -001, -019, -017),
 )
 
 const queen = #(
-  #(-20, -10, -10, -5, -5, -10, -10, -20),
-  #(-10, 0, 0, 0, 0, 0, 0, -10),
-  #(-10, 0, 5, 5, 5, 5, 0, -10),
-  #(-5, 0, 5, 5, 5, 5, 0, -5),
-  #(0, 0, 5, 5, 5, 5, 0, -5),
-  #(-10, 5, 5, 5, 5, 5, 0, -10),
-  #(-10, 0, 5, 0, 0, 0, 0, -10),
-  #(-20, -10, -10, -5, -5, -10, -10, -20),
+  #(003, -005, -005, 004, 004, -005, -005, 003),
+  #(-003, 005, 008, 012, 012, 008, 005, -003),
+  #(-003, 006, 013, 007, 007, 013, 006, -003),
+  #(004, 005, 009, 008, 008, 009, 005, 004),
+  #(000, 014, 012, 005, 005, 012, 014, 000),
+  #(-004, 010, 006, 008, 008, 006, 010, -004),
+  #(-005, 006, 010, 008, 008, 010, 006, -005),
+  #(-002, -002, 001, -002, -002, 001, -002, -002),
 )
 
 const king = #(
-  #(-30, -40, -40, -50, -50, -40, -40, -30),
-  #(-30, -40, -40, -50, -50, -40, -40, -30),
-  #(-30, -40, -40, -50, -50, -40, -40, -30),
-  #(-30, -40, -40, -50, -50, -40, -40, -30),
-  #(-20, -30, -30, -40, -40, -30, -30, -20),
-  #(-10, -20, -20, -20, -20, -20, -20, -10),
-  #(20, 20, 0, 0, 0, 0, 20, 20),
-  #(20, 30, 10, 0, 0, 10, 30, 20),
-)
-
-/// In the beginning and middle of the game, the king must be kept safe. However
-/// as the game progresses towards the end, the king should become more aggressive
-/// so we use a different set of scores for kings in the endgame.
-const king_endgame = #(
-  #(-50, -40, -30, -20, -20, -30, -40, -50),
-  #(-30, -20, -10, 0, 0, -10, -20, -30),
-  #(-30, -10, 20, 30, 30, 20, -10, -30),
-  #(-30, -10, 30, 40, 40, 30, -10, -30),
-  #(-30, -10, 30, 40, 40, 30, -10, -30),
-  #(-30, -10, 20, 30, 30, 20, -10, -30),
-  #(-30, -30, 0, 0, 0, 0, -30, -30),
-  #(-50, -30, -30, -30, -30, -30, -30, -50),
+  #(271, 327, 271, 198, 198, 271, 327, 271),
+  #(278, 303, 234, 179, 179, 234, 303, 278),
+  #(195, 258, 169, 120, 120, 169, 258, 195),
+  #(164, 190, 138, 098, 098, 138, 190, 164),
+  #(154, 179, 105, 070, 070, 105, 179, 154),
+  #(123, 145, 081, 031, 031, 081, 145, 123),
+  #(088, 120, 065, 033, 033, 065, 120, 088),
+  #(059, 089, 045, -001, -001, 045, 089, 059),
 )
 
 /// In the middlegame, pawns are encouraged to protect the king's castling
 /// squares. In the endgame though, they no longer need to protect the king and
 /// instead should promote. Therefore, we use a different table to encourage this.
 const pawn_endgame = #(
-  #(100, 100, 100, 100, 100, 100, 100, 100),
-  #(80, 80, 80, 80, 80, 80, 80, 80),
-  #(50, 50, 50, 50, 50, 50, 50, 50),
-  #(30, 30, 30, 30, 30, 30, 30, 30),
-  #(10, 10, 10, 10, 10, 10, 10, 10),
-  // Since pawns can double-move, the first two ranks are equivalent from the
-  // pawn's perspective.
-  #(-10, -10, -10, -10, -10, -10, -10, -10),
-  #(-10, -10, -10, -10, -10, -10, -10, -10),
-  #(-10, -10, -10, -10, -10, -10, -10, -10),
+  #(000, 000, 000, 000, 000, 000, 000, 000),
+  #(-010, -006, 010, 000, 014, 007, -005, -019),
+  #(-010, -010, -010, 004, 004, 003, -006, -004),
+  #(006, -002, -008, -004, -013, -012, -010, -009),
+  #(010, 005, 004, -005, -005, -005, 014, 009),
+  #(028, 020, 021, 028, 030, 007, 006, 013),
+  #(000, -011, 012, 021, 025, 019, 004, 007),
+  #(000, 000, 000, 000, 000, 000, 000, 000),
+)
+
+const knight_endgame = #(
+  #(-096, -065, -049, -021, -021, -049, -065, -096),
+  #(-067, -054, -018, 008, 008, -018, -054, -067),
+  #(-040, -027, -008, 029, 029, -008, -027, -040),
+  #(-035, -002, 013, 028, 028, 013, -002, -035),
+  #(-045, -016, 009, 039, 039, 009, -016, -045),
+  #(-051, -044, -016, 017, 017, -016, -044, -051),
+  #(-069, -050, -051, 012, 012, -051, -050, -069),
+  #(-100, -088, -056, -017, -017, -056, -088, -100),
+)
+
+const bishop_endgame = #(
+  #(-057, -030, -037, -012, -012, -037, -030, -057),
+  #(-037, -013, -017, 001, 001, -017, -013, -037),
+  #(-016, -001, -002, 010, 010, -002, -001, -016),
+  #(-020, -006, 000, 017, 017, 000, -006, -020),
+  #(-017, -001, -014, 015, 015, -014, -001, -017),
+  #(-030, 006, 004, 006, 006, 004, 006, -030),
+  #(-031, -020, -001, 001, 001, -001, -020, -031),
+  #(-046, -042, -037, -024, -024, -037, -042, -046),
+)
+
+const rook_endgame = #(
+  #(-009, -013, -010, -009, -009, -010, -013, -009),
+  #(-012, -009, -001, -002, -002, -001, -009, -012),
+  #(006, -008, -002, -006, -006, -002, -008, 006),
+  #(-006, 001, -009, 007, 007, -009, 001, -006),
+  #(-005, 008, 007, -006, -006, 007, 008, -005),
+  #(006, 001, -007, 010, 010, -007, 001, 006),
+  #(004, 005, 020, -005, -005, 020, 005, 004),
+  #(018, 000, 019, 013, 013, 019, 000, 018),
+)
+
+const queen_endgame = #(
+  #(-069, -057, -047, -026, -026, -047, -057, -069),
+  #(-055, -031, -022, -004, -004, -022, -031, -055),
+  #(-039, -018, -009, 003, 003, -009, -018, -039),
+  #(-023, -003, 013, 024, 024, 013, -003, -023),
+  #(-029, -006, 009, 021, 021, 009, -006, -029),
+  #(-038, -018, -012, 001, 001, -012, -018, -038),
+  #(-050, -027, -024, -008, -008, -024, -027, -050),
+  #(-075, -052, -043, -036, -036, -043, -052, -075),
+)
+
+/// In the beginning and middle of the game, the king must be kept safe. However
+/// as the game progresses towards the end, the king should become more aggressive
+/// so we use a different set of scores for kings in the endgame.
+const king_endgame = #(
+  #(001, 045, 085, 076, 076, 085, 045, 001),
+  #(053, 100, 133, 135, 135, 133, 100, 053),
+  #(088, 130, 169, 175, 175, 169, 130, 088),
+  #(103, 156, 172, 172, 172, 172, 156, 103),
+  #(096, 166, 199, 199, 199, 199, 166, 096),
+  #(092, 172, 184, 191, 191, 184, 172, 092),
+  #(047, 121, 116, 131, 131, 116, 121, 047),
+  #(011, 059, 073, 078, 078, 073, 059, 011),
 )
 
 type Table =
···
   let table = case piece {
     board.Pawn -> pawn_endgame
     board.King -> king_endgame
-    board.Bishop -> bishop
-    board.Knight -> knight
-    board.Queen -> queen
-    board.Rook -> rook
+    board.Bishop -> bishop_endgame
+    board.Knight -> knight_endgame
+    board.Queen -> queen_endgame
+    board.Rook -> rook_endgame
   }
 
   get(table, position, colour)