Issue/528 tdd the chess eval combined attack eval class (#541)

* Refactored Chess\Eval\ThreatEval * Refactored Chess\Eval\ThreatEval * Refactored Chess\Eval\ThreatEval * TDDed the Chess\Eval\ThreatEval class * Updated ThreatEvalTest * Fixed Chess\Eval\SqCount * Fixed Chess\Eval\ThreatEval * Updated tests * Refactored Chess\Eval\ThreatEval * Documented the Chess\Eval\ThreatEval class
chesslablab · May 24, 2024 · 393740d · 393740d
1 parent 0c5af2f
commit 393740d
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Showing 6 changed files with 125 additions and 49 deletions.
diff --git a/src/Eval/SqCount.php b/src/Eval/SqCount.php
@@ -60,6 +60,11 @@ private function free(): array
      */
     private function used(): object
     {
+        $used = [
+            Color::W => [],
+            Color::B => [],
+        ];
+
         foreach ($this->board->getPieces() as $piece) {
             $used[$piece->getColor()][] = $piece->getSq();
         }

diff --git a/src/Eval/ThreatEval.php b/src/Eval/ThreatEval.php
@@ -3,9 +3,18 @@
 namespace Chess\Eval;
 
 use Chess\Piece\AbstractPiece;
-use Chess\Tutor\PiecePhrase;
 use Chess\Variant\Classical\Board;
-
+use Chess\Variant\Classical\PGN\AN\Color;
+use Chess\Variant\Classical\PGN\AN\Piece;
+
+/**
+ * Threat evaluation.
+ *
+ * Total piece value obtained from the squares under threat of being attacked.
+ *
+ * @author Jordi Bassagaña
+ * @license MIT
+ */
 class ThreatEval extends AbstractEval implements
     ElaborateEvalInterface,
     ExplainEvalInterface
@@ -15,11 +24,16 @@ class ThreatEval extends AbstractEval implements
 
     const NAME = 'Threat';
 
+    /**
+     * Constructor.
+     *
+     * @param \Chess\Variant\Classical\Board $board
+     */
     public function __construct(Board $board)
     {
         $this->board = $board;
 
-        $this->range = [1, 5];
+        $this->range = [0.8, 5];
 
         $this->subject = [
             'White',
@@ -32,49 +46,55 @@ public function __construct(Board $board)
             "has a total threat advantage",
         ];
 
-        foreach ($this->board->getPieces() as $piece) {
-            $countAttacking = count($piece->attackingPieces());
-            $countDefending = count($piece->defendingPieces());
-            $diff = $countAttacking - $countDefending;
-            if ($diff > 0 && $countDefending > 0) {
-                $valueDefending = $this->valueDefending($piece->defendingPieces());
-                $valueAttacking = $this->valueAttacking($piece->attackingPieces());
-                if (($valueDefending + self::$value[$piece->getId()]) >= $valueAttacking) {
-                    $this->result[$piece->oppColor()] += $diff;
-                    $this->elaborate($piece);
+        if (!$this->board->isMate()) {
+            foreach ($this->board->getPieces() as $piece) {
+                if ($piece->getId() !== Piece::K) {
+                    $clone = unserialize(serialize($this->board));
+                    $clone->setTurn($piece->oppColor());
+                    $threat = [
+                        Color::W => 0,
+                        Color::B => 0,
+                    ];
+                    $attackingPiece = current($piece->attackingPieces());
+                    while ($attackingPiece) {
+                        $capturedPiece = $clone->getPieceBySq($piece->getSq());
+                        if ($clone->playLan($clone->getTurn(), $attackingPiece->getSq() . $piece->getSq())) {
+                            $threat[$attackingPiece->getColor()] += self::$value[$capturedPiece->getId()];
+                            if ($defendingPiece = current($piece->defendingPieces())) {
+                                $capturedPiece = $clone->getPieceBySq($piece->getSq());
+                                if ($clone->playLan($clone->getTurn(), $defendingPiece->getSq() . $piece->getSq())) {
+                                    $threat[$defendingPiece->getColor()] += self::$value[$capturedPiece->getId()];
+                                }
+                            }
+                            $attackingPiece = current($clone->getPieceBySq($piece->getSq())->attackingPieces());
+                        }
+                    }
+                    $diff = $threat[Color::W] - $threat[Color::B];
+                    if ($piece->oppColor() === Color::W) {
+                        if ($diff > 0) {
+                            $this->result[Color::W] += $diff;
+                            $this->elaborate($piece);
+                        }
+                    } else {
+                        if ($diff < 0) {
+                            $this->result[Color::B] += abs($diff);
+                            $this->elaborate($piece);
+                        }
+                    }
                 }
             }
         }
 
         $this->explain($this->result);
     }
 
-    private function valueDefending(array $pieces)
-    {
-        $sum = 0;
-        foreach ($pieces as $piece) {
-            $sum += self::$value[$piece->getId()];
-        }
-
-        return $sum;
-    }
-
-    private function valueAttacking(array $pieces)
-    {
-        $values = [];
-        foreach ($pieces as $piece) {
-            $values[] = self::$value[$piece->getId()];
-        }
-        sort($values);
-        array_pop($values);
-
-        return array_sum($values);
-    }
-
+    /**
+     * Elaborate on the result.
+     *
+     * @param \Chess\Piece\AbstractPiece $piece
+     */
     private function elaborate(AbstractPiece $piece): void
     {
-        $phrase = PiecePhrase::create($piece);
-
-        $this->elaboration[] = ucfirst("$phrase is being threatened and may be lost if not defended properly.");
+        $this->elaboration[] = "The {$piece->getSq()}-square is under threat of being attacked.";
     }
 }
diff --git a/src/Variant/Classical/AbstractPgnParser.php b/src/Variant/Classical/AbstractPgnParser.php
@@ -21,7 +21,7 @@
  *
  * The root class in the hierarchy of chess boards defines the getter and the
  * setter methods, in addition to implementing the internal methods required to
- * convert a PGN move in text format into a data structure. 
+ * convert a PGN move in text format into a data structure.
  *
  * @author Jordi Bassagaña
  * @license MIT

diff --git a/tests/unit/Eval/ThreatEvalTest.php b/tests/unit/Eval/ThreatEvalTest.php
@@ -12,6 +12,32 @@ class ThreatEvalTest extends AbstractUnitTestCase
      * @test
      */
     public function B21()
+    {
+        $expectedResult = [
+            'w' => 0,
+            'b' => 2.33,
+        ];
+
+        $expectedExplanation = [
+            "Black has a slight threat advantage.",
+        ];
+
+        $expectedElaboration = [
+            "The c4-square is under threat of being attacked.",
+        ];
+
+        $board = (new StrToBoard('r1bqkbnr/5ppp/p1npp3/1p6/2B1P3/2N2N2/PP2QPPP/R1B2RK1 w kq b6'))->create();
+        $threatEval = new ThreatEval($board);
+
+        $this->assertSame($expectedResult, $threatEval->getResult());
+        $this->assertSame($expectedExplanation, $threatEval->getExplanation());
+        $this->assertSame($expectedElaboration, $threatEval->getElaboration());
+    }
+
+    /**
+     * @test
+     */
+    public function B21_Bb3()
     {
         $expectedResult = [
             'w' => 0,
@@ -22,7 +48,7 @@ public function B21()
 
         $expectedElaboration = [];
 
-        $board = (new StrToBoard('r1bqkbnr/5ppp/p1npp3/1p6/2B1P3/2N2N2/PP2QPPP/R1B2RK1 w kq b6'))->create();
+        $board = (new StrToBoard('r1bqkbnr/5ppp/p1npp3/1p6/4P3/1BN2N2/PP2QPPP/R1B2RK1 b kq -'))->create();
         $threatEval = new ThreatEval($board);
 
         $this->assertSame($expectedResult, $threatEval->getResult());
@@ -36,7 +62,7 @@ public function B21()
     public function middlegame()
     {
         $expectedResult = [
-            'w' => 1,
+            'w' => 0.8700000000000001,
             'b' => 0,
         ];
 
@@ -45,7 +71,7 @@ public function middlegame()
         ];
 
         $expectedElaboration = [
-            "The knight on b5 is being threatened and may be lost if not defended properly.",
+            "The b5-square is under threat of being attacked.",
         ];
 
         $board = (new StrToBoard('r1bqkbnr/5ppp/p1npp3/1n6/2B1P3/2N2N2/PP2QPPP/R1B2RK1 w kq b6'))->create();
@@ -63,15 +89,15 @@ public function endgame()
     {
         $expectedResult = [
             'w' => 0,
-            'b' => 1,
+            'b' => 1.0,
         ];
 
         $expectedExplanation = [
             "Black has a slight threat advantage.",
         ];
 
         $expectedElaboration = [
-            "The pawn on d4 is being threatened and may be lost if not defended properly.",
+            "The d4-square is under threat of being attacked.",
         ];
 
         $board = (new StrToBoard('6k1/6p1/2n2b2/8/3P4/5N2/2K5/8 w - -'))->create();
@@ -81,4 +107,25 @@ public function endgame()
         $this->assertSame($expectedExplanation, $threatEval->getExplanation());
         $this->assertSame($expectedElaboration, $threatEval->getElaboration());
     }
+
+    /**
+     * @test
+     */
+    public function w_N_c2()
+    {
+        $expectedResult = [
+            'w' => 0,
+            'b' => 3.2,
+        ];
+
+        $expectedExplanation = [
+            "Black has a moderate threat advantage.",
+        ];
+
+        $board = (new StrToBoard('2r3k1/8/8/2q5/8/8/2N5/1K6 w - -'))->create();
+        $threatEval = new ThreatEval($board);
+
+        $this->assertSame($expectedResult, $threatEval->getResult());
+        $this->assertSame($expectedExplanation, $threatEval->getExplanation());
+    }
 }
diff --git a/tests/unit/Heuristics/SanHeuristicsTest.php b/tests/unit/Heuristics/SanHeuristicsTest.php
@@ -93,7 +93,7 @@ public function get_balance_e4_e6_d4_d5()
             [ 0, 0.86, -0.8, 1.0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ],
             [ 0, 0.21, -0.4, 0.13, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ],
             [ 0, 1.0, -1.0, 0.88, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ],
-            [ 0, 0.64, -0.6, 0.63, 0, 0, -1.0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ],
+            [ 0, 0.64, -0.6, 0.63, 0, 0, -1.0, -1.0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ],
         ];
 
         $this->assertEquals($expected, $balance);
@@ -113,7 +113,7 @@ public function get_balance_e4_e6_d4_d5_Nd2_Nf6()
             [ 0, 0.86, -0.8, 1.0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ],
             [ 0, 0.21, -0.4, 0.13, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ],
             [ 0, 1.0, -1.0, 0.88, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ],
-            [ 0, 0.64, -0.6, 0.63, 0, 0, -1.0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ],
+            [ 0, 0.64, -0.6, 0.63, 0, 0, -1.0, -0.31, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ],
             [ 0, 0.59, 1.0, 0.25, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ],
             [ 0, 0.27, -0.8, 0.25, -1.0, 0, 0, -1.0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ],
         ];
@@ -161,7 +161,7 @@ public function get_balance_scholar_checkmate()
             [ 0, 0.56, -0.07, 0.13, 0.25, 0.25, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ],
             [ 0, 0.19, -0.36, 0, 0.25, 0.25, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ],
             [ 0, 0.36, -0.64, 0.5, 1.0, 0.25, 0, 1.0, 0, 0, 0, 0, 0, 0, 0, 0, 1.0, 0.0, 1.0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ],
-            [ 0, -1.0, -1.0, 0.5, 0.5, 0.25, -1.0, 1.0, -1.0, 0, 0, 0, 0, 0, 0, 0, 1.0, 0.0, 1.0, 0, 0, -1.0, 0, 0, 0, 0, 0, 0, 0 ],
+            [ 0, -1.0, -1.0, 0.5, 0.5, 0.25, -1.0, -1.0, -1.0, 0, 0, 0, 0, 0, 0, 0, 1.0, 0, 1.0, 0, 0, -1.0, 0, 0, 0, 0, 0, 0, 0 ],
             [ 1.0, 0.47, -0.86, 0.25, 0.75, 1.0, -0.1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0.2, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1.0, 0, 0 ],
         ];
 

diff --git a/tests/unit/Tutor/PgnEvaluationTest.php b/tests/unit/Tutor/PgnEvaluationTest.php
@@ -17,8 +17,10 @@ public function A08()
         $expected = [
             "Black has a slight space advantage.",
             "White has a slight protection advantage.",
+            "White has a slight threat advantage.",
             "The pawn on c5 is unprotected.",
-            "Overall, 2 heuristic evaluation features are favoring White while 2 are favoring Black.",
+            "The c5-square is under threat of being attacked.",
+            "Overall, 3 heuristic evaluation features are favoring White while 2 are favoring Black.",
         ];
 
         $A08 = file_get_contents(self::DATA_FOLDER.'/sample/A08.pgn');
@@ -39,8 +41,10 @@ public function endgame()
             "White has a total space advantage.",
             "The white pieces are timidly approaching the other side's king.",
             "Black has a decisive protection advantage.",
+            "Black has a moderate threat advantage.",
             "The bishop on e6 is unprotected.",
-            "Overall, 6 heuristic evaluation features are favoring White while 1 is favoring Black.",
+            "The e6-square is under threat of being attacked.",
+            "Overall, 6 heuristic evaluation features are favoring White while 2 are favoring Black.",
         ];
 
         $board = FenToBoardFactory::create('8/5k2/4n3/8/8/1BK5/1B6/8 w - - 0 1');