added fraction simplifications score answer impl

reasoning_gym/arithmetic/fraction_simplification.py

@@ -1,12 +1,16 @@
 """Fraction simplification task generator"""
 
+import re
 from dataclasses import dataclass
 from math import gcd
 from random import Random
-from typing import Optional, Sequence, Tuple
+from typing import Any, Dict, Optional, Sequence, Tuple
 
 from ..factory import ProceduralDataset, register_dataset
 
+QUESTION_TEMPLATE = """Simplify the fraction {question_fraction} to its lowest terms. Give only the simplified fraction
+                       as your final answer."""
+
 
 @dataclass
 class FractionSimplificationConfig:
@@ -107,7 +111,7 @@ class FractionSimplificationDataset(ProceduralDataset):
         answer_fraction = self._format_fraction(simple_num, simple_den, style)
 
         return {
-            "question": f"Simplify the fraction {question_fraction} to its lowest terms",
+            "question": QUESTION_TEMPLATE.format(question_fraction=question_fraction),
             "answer": answer_fraction,
             "metadata": {
                 "numerator": num,
@@ -119,5 +123,34 @@ class FractionSimplificationDataset(ProceduralDataset):
             },
         }
 
+    def _extract_fraction(self, answer: Optional[str]):
+        try:
+            cleaned = answer.strip().strip("$").strip()
+            latex_match = re.match(r"\\(?:frac|dfrac)\s*{\s*(\d+)\s*}\s*{\s*(\d+)\s*}", cleaned, re.IGNORECASE)
+            if latex_match:
+                return int(latex_match.group(1)), int(latex_match.group(2))
+            if "/" in cleaned:
+                numerator, denominator = map(str.strip, cleaned.split("/", 1))
+                return int(numerator), int(denominator)
+        except:
+            return None
+
+    def score_answer(self, answer: Optional[str], entry: Dict[str, Any]):
+        reward = 0.0
+        metadata = entry["metadata"]
+        try:
+            numerator, denominator = self._extract_fraction(answer)
+            if numerator == metadata["simplified_numerator"] and denominator == metadata["simplified_denominator"]:
+                reward = 1.0
+            elif numerator == metadata["numerator"] or denominator == metadata["denominator"]:
+                reward = 0.1
+            elif len(answer.strip()) > 0:
+                reward = 0.05
+            else:
+                reward = 0.01
+        except:
+            reward = 0.01
+        return reward
+
 
 register_dataset("fraction_simplification", FractionSimplificationDataset, FractionSimplificationConfig)