Enable rounding for Decimal32 and Decimal64 in cuDF

python/cudf/cudf/core/indexed_frame.py

@@ -3936,7 +3936,7 @@ def round(self, decimals=0, how="half_even"):
 
         cols = (
             col.round(decimals[name], how=how)
-            if name in decimals and col.dtype.kind in "fiu"
+            if name in decimals and (col.dtype.kind in "fiu" or isinstance(col.dtype, (cudf.Decimal32Dtype, cudf.Decimal64Dtype)))
             else col.copy(deep=True)
             for name, col in self._column_labels_and_values
         )

python/cudf/cudf/tests/test_series.py

@@ -14,6 +14,9 @@
 import pytest
 
 import cudf
+from cudf.core.dtypes import Decimal32Dtype
+from cudf.core.dtypes import Decimal64Dtype
+
 from cudf.api.extensions import no_default
 from cudf.core._compat import PANDAS_CURRENT_SUPPORTED_VERSION, PANDAS_VERSION
 from cudf.errors import MixedTypeError
@@ -772,6 +775,40 @@ def test_round_nan_as_null_false(series, decimal):
     assert_eq(result, expected, atol=1e-10)
 
 
+@pytest.mark.parametrize(
+    "data, dtype, decimals, expected_half_up, expected_half_even",
+    [
+        # Decimal32Dtype Test Cases
+        ([1.234, 2.345, 3.456], Decimal32Dtype(precision=5, scale=3), 2, [1.23, 2.35, 3.46], [1.23, 2.34, 3.46]),
+        ([1.234, 2.345, 3.456], Decimal32Dtype(precision=5, scale=3), 0, [1.0, 2.0, 3.0], [1.0, 2.0, 3.0]),
+        ([1.234, 2.345, 3.456], Decimal32Dtype(precision=5, scale=3), 3, [1.234, 2.345, 3.456], [1.234, 2.345, 3.456]),
+        # Decimal64Dtype Test Cases
+        ([1.234567, 2.345678, 3.456789], Decimal64Dtype(precision=10, scale=6), 4, [1.2346, 2.3457, 3.4568], [1.2346, 2.3457, 3.4568]),
+        ([1.234567, 2.345678, 3.456789], Decimal64Dtype(precision=10, scale=6), 2, [1.23, 2.35, 3.46], [1.23, 2.35, 3.46]),
+        ([1.234567, 2.345678, 3.456789], Decimal64Dtype(precision=10, scale=6), 6, [1.234567, 2.345678, 3.456789], [1.234567, 2.345678, 3.456789]),
+    ],
+)
+def test_series_round_decimal(data, dtype, decimals, expected_half_up, expected_half_even):
+    ser = cudf.Series(data).astype(dtype)
+
+    # Half-up rounding
+    result_half_up = ser.round(decimals=decimals, how="half_up").astype(dtype)
+    # print("Rounded Series (half_up):", result_half_up)
+
+    expected_ser_half_up = cudf.Series(expected_half_up).astype(dtype)
+    # print("Expected Series (half_up):", expected_ser_half_up)
+
+    assert_eq(result_half_up, expected_ser_half_up)
+
+    # Half-even rounding
+    result_half_even = ser.round(decimals=decimals, how="half_even").astype(dtype)
+    # print("Rounded Series (half_even):", result_half_even)
+
+    expected_ser_half_even = cudf.Series(expected_half_even).astype(dtype)
+    # print("Expected Series (half_even):", expected_ser_half_even)
+    assert_eq(result_half_even, expected_ser_half_even)     
+
+
 @pytest.mark.parametrize("ps", _series_na_data())
 @pytest.mark.parametrize("nan_as_null", [True, False, None])
 def test_series_isnull_isna(ps, nan_as_null):