fixes

reasoning_gym/graphs/path_star.py

@@ -30,6 +30,8 @@ Solve the following task:
 
 @dataclass
 class PathStarConfig:
+    """Configuration for Path Star dataset generation"""
+
     degree: int = 3
     node_range: int = 100_000
     min_path_length: int = 3
@@ -41,8 +43,13 @@ class PathStarConfig:
     seed: Optional[int] = None
 
     def validate(self) -> None:
-        assert self.degree >= 2 and self.min_path_length >= 1
-        assert self.node_range > self.degree * self.max_path_length + 1
+        """Validate configuration parameters"""
+        assert self.degree >= 2, "degree must be at least 2"
+        assert self.min_path_length >= 1, "min_path_length must be at least 1"
+        assert self.min_path_length <= self.max_path_length, "min_path_length must be <= max_path_length"
+        assert (
+            self.node_range > self.degree * self.max_path_length + 1
+        ), "node_range must exceed degree * max_path_length + 1 for unique labels"
 
 
 class PathStarDataset(ProceduralDataset):
@@ -51,6 +58,17 @@ class PathStarDataset(ProceduralDataset):
     def __init__(self, config: PathStarConfig):
         super().__init__(config=config, seed=config.seed, size=config.size)
 
+    def score_answer(self, answer: Optional[str], entry: dict[str, Any]) -> float:
+        """Score an answer. Path is unique in a star graph, so only exact match counts."""
+        if not isinstance(answer, str) or len(answer.strip()) == 0:
+            return 0.0
+        # Normalize: strip, collapse whitespace
+        answer_normalized = " ".join(answer.strip().split())
+        oracle_normalized = " ".join(entry["answer"].strip().split())
+        if answer_normalized == oracle_normalized:
+            return 1.0
+        return 0.0
+
     def __getitem__(self, idx: int) -> dict[str, Any]:
         rng = random.Random(self.seed + idx)
 
@@ -81,7 +99,10 @@ class PathStarDataset(ProceduralDataset):
         rng.shuffle(edges)
 
         edges_str = "".join(f"|{u} {v}" for u, v in edges)
-        prefix = f"{edges_str}/{center} {goal} = "
+        if cfg.reversed:
+            prefix = f"{edges_str}/{goal} {center} = "
+        else:
+            prefix = f"{edges_str}/{center} {goal} = "
         question = PROMPT_TEMPLATE.format(task=prefix)
 
         # gold path
@@ -94,6 +115,8 @@ class PathStarDataset(ProceduralDataset):
             "question": question,
             "answer": answer,
             "metadata": {
+                "source_dataset": DATASET_NAME,
+                "source_index": idx,
                 "center": center,
                 "goal": goal,
                 "path_length": path_length,