dice curriculum (#284)

* curriculum + unit tests
* add difficulty to metadata

---------

Co-authored-by: Andreas Koepf <andreas.koepf@provisio.com>

reasoning_gym/arithmetic/dice.py

@@ -4,6 +4,7 @@ from math import gcd
 from random import Random
 from typing import Any, Optional
 
+from ..coaching import AttributeType, BaseCurriculum, ScalarAttributeDefinition
 from ..factory import ProceduralDataset, register_dataset
 
 
@@ -75,7 +76,7 @@ def generate_puzzle(num_dice, max_dice_size, rng):
     target = rng.randint(low_target, high_target)
 
     # Compute probability.
-    (num, den), prob = compute_probability(dice, target)
+    (num, den) = compute_probability(dice, target)
 
     # Create a string representing the dice, e.g., "1d20, 1d17, 1d6" etc.
     dice_str = ", ".join(f"1d{s}" for s in dice)
@@ -122,7 +123,12 @@ class DiceDataset(ProceduralDataset):
         return {
             "question": puzzle_str,
             "answer": answer_str,
-            "metadata": {},
+            "metadata": {
+                "difficulty": {
+                    "num_dice": self.config.num_dice,
+                    "max_dice_size": self.config.max_dice_size,
+                }
+            },
         }
 
     def score_answer(self, answer: Optional[str], entry: dict[str, Any]) -> float:
@@ -145,4 +151,32 @@ class DiceDataset(ProceduralDataset):
         return 0.0
 
 
-register_dataset("dice", DiceDataset, DiceConfig)
+class DiceCurriculum(BaseCurriculum):
+    """Curriculum for dice puzzle generation"""
+
+    def __init__(self):
+        super().__init__(DiceCurriculum.__name__, DiceConfig)
+
+        self._define_attributes(
+            ScalarAttributeDefinition(
+                name="num_dice",
+                levels=[4, 5, 6, 7],
+                default_level=0,
+                description="Number of dice to roll",
+                attr_type=AttributeType.STATIC,
+                min_value=4,
+                field_name="num_dice",
+            ),
+            ScalarAttributeDefinition(
+                name="max_dice_size",
+                levels=[20, 25, 30, 35],
+                default_level=0,
+                description="Maximum number of sides on any die",
+                attr_type=AttributeType.STATIC,
+                min_value=20,
+                field_name="max_dice_size",
+            ),
+        )
+
+
+register_dataset("dice", DiceDataset, DiceConfig, DiceCurriculum)