1 files changed, 51 insertions, 0 deletions
diff --git a/dataset/common.py b/dataset/common.py
new file mode 100644
index 0000000..7bc51c6
--- /dev/null
+++ b/dataset/common.py
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+from typing import List, Optional
+
+import pydantic
+import numpy as np
+
+
+# Global list mapping each dihedral transform id to its inverse.
+# Index corresponds to the original tid, and the value is its inverse.
+DIHEDRAL_INVERSE = [0, 3, 2, 1, 4, 5, 6, 7]
+
+
+class PuzzleDatasetMetadata(pydantic.BaseModel):
+    pad_id: int
+    ignore_label_id: Optional[int]
+    blank_identifier_id: int
+    
+    vocab_size: int
+    seq_len: int
+    num_puzzle_identifiers: int
+    
+    total_groups: int
+    mean_puzzle_examples: float
+
+    sets: List[str]
+
+
+def dihedral_transform(arr: np.ndarray, tid: int) -> np.ndarray:
+    """8 dihedral symmetries by rotate, flip and mirror"""
+    
+    if tid == 0:
+        return arr  # identity
+    elif tid == 1:
+        return np.rot90(arr, k=1)
+    elif tid == 2:
+        return np.rot90(arr, k=2)
+    elif tid == 3:
+        return np.rot90(arr, k=3)
+    elif tid == 4:
+        return np.fliplr(arr)       # horizontal flip
+    elif tid == 5:
+        return np.flipud(arr)       # vertical flip
+    elif tid == 6:
+        return arr.T                # transpose (reflection along main diagonal)
+    elif tid == 7:
+        return np.fliplr(np.rot90(arr, k=1))  # anti-diagonal reflection
+    else:
+        return arr
+    
+    
+def inverse_dihedral_transform(arr: np.ndarray, tid: int) -> np.ndarray:
+    return dihedral_transform(arr, DIHEDRAL_INVERSE[tid])