public code v1

pygrex/evaluator/explainer_evaluator.py

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+from typing import Dict, Any
+
+from pygrex.utils import calculate_gild_for_explanations
+
+
+class ExplanationEvaluator:
+    """
+    A unified evaluator for different explanation methods.
+
+    This class takes the results generated by an explainer and calculates
+    a standard set of quality metrics, such as Fidelity and Diversity (GILD).
+    """
+
+    def __init__(self):
+        """Initializes the ExplanationEvaluator."""
+        # This class is stateless, so __init__ is simple.
+        pass
+
+    def evaluate(
+        self, explanation_results: Dict[str, Any], explainer_type: str
+    ) -> Dict[str, float]:
+        """
+        Calculates all relevant metrics for a given explanation result.
+
+        Args:
+            explanation_results: The dictionary returned by an explainer's
+                                 `find_explanation` method.
+            explainer_type: A string identifier for the explainer used
+                            (e.g., "LORE4Groups", "EXPGRS").
+
+        Returns:
+            A dictionary containing the calculated metric scores.
+        """
+        if not explanation_results:
+            return {"fidelity": 0.0, "gild": 0.0}
+
+        fidelity = self._calculate_fidelity(explanation_results)
+        gild = self._calculate_gild(explanation_results, explainer_type)
+
+        return {"fidelity": fidelity, "gild": gild}
+
+    def _calculate_fidelity(self, explanation_results: Dict[str, Any]) -> float:
+        """
+        Extracts the fidelity score from the explanation results.
+
+        Fidelity is computed by the explainer itself, as it's the ratio of
+        items it was able to explain. This method standardizes its retrieval.
+        """
+        return explanation_results.get("fidelity", 0.0)
+
+    def _calculate_gild(
+        self, explanation_results: Dict[str, Any], explainer_type: str
+    ) -> float:
+        """
+        Calculates the Gaussian Inter-List Diversity (GILD) of the explanations.
+
+        This is a wrapper around the utility function that handles the details.
+        It uses the 'details' part of the explanation results.
+        """
+        explanation_details = explanation_results.get("details", {})
+        if not explanation_details:
+            return 0.0
+
+        # The GILD function is now called from a central, logical place.
+        gild_score = calculate_gild_for_explanations(
+            explanation_details, explainer_type
+        )
+        return gild_score