FEAT-#2091: add distributed dataframe compare (#2579)

Signed-off-by: Khang Vu <[email protected]>

docs/supported_apis/dataframe_supported.rst

@@ -79,7 +79,7 @@ default to pandas.
 +----------------------------+---------------------------+------------------------+----------------------------------------------------+
 | ``combine_first``          | `combine_first`_          | Y                      |                                                    |
 +----------------------------+---------------------------+------------------------+----------------------------------------------------+
-| ``compare``                | `compare`_                | D                      |                                                    |
+| ``compare``                | `compare`_                | Y                      |                                                    |
 +----------------------------+---------------------------+------------------------+----------------------------------------------------+
 | ``copy``                   | `copy`_                   | Y                      |                                                    |
 +----------------------------+---------------------------+------------------------+----------------------------------------------------+

docs/supported_apis/series_supported.rst

@@ -90,7 +90,7 @@ the related section on `Defaulting to pandas`_.
 +-----------------------------+---------------------------------+----------------------------------------------------+
 | ``combine_first``           | Y                               |                                                    |
 +-----------------------------+---------------------------------+----------------------------------------------------+
-| ``compare``                 | D                               |                                                    |
+| ``compare``                 | Y                               |                                                    |
 +-----------------------------+---------------------------------+----------------------------------------------------+
 | ``compress``                | D                               |                                                    |
 +-----------------------------+---------------------------------+----------------------------------------------------+

modin/backends/base/query_compiler.py

@@ -1884,5 +1884,6 @@ def set_index_names(self, names, axis=0):
     kurt = DataFrameDefault.register(pandas.DataFrame.kurt)
     sum_min_count = DataFrameDefault.register(pandas.DataFrame.sum)
     prod_min_count = DataFrameDefault.register(pandas.DataFrame.prod)
+    compare = DataFrameDefault.register(pandas.DataFrame.compare)
 
     # End of DataFrame methods

modin/backends/pandas/query_compiler.py

@@ -3023,3 +3023,12 @@ def cat_codes(self):
         return self.default_to_pandas(lambda df: df[df.columns[0]].cat.codes)
 
     # END Cat operations
+
+    def compare(self, other, **kwargs):
+        return self.__constructor__(
+            self._modin_frame.broadcast_apply_full_axis(
+                0,
+                lambda l, r: pandas.DataFrame.compare(l, r, **kwargs),
+                other._modin_frame,
+            )
+        )

modin/pandas/base.py

@@ -207,6 +207,7 @@ def _validate_other(
         numeric_or_time_only=False,
         numeric_or_object_only=False,
         comparison_dtypes_only=False,
+        compare_index=False,
     ):
         """
         Help to check validity of other in inter-df operations.
@@ -260,6 +261,9 @@ def _validate_other(
                     else len(self._query_compiler.columns)
                 )
             ]
+        if compare_index:
+            if not self.index.equals(other.index):
+                raise TypeError("Cannot perform operation with non-equal index")
         # Do dtype checking.
         if numeric_only:
             if not all(

modin/pandas/dataframe.py

@@ -566,12 +566,16 @@ def compare(
         keep_shape: bool = False,
         keep_equal: bool = False,
     ) -> "DataFrame":
-        return self._default_to_pandas(
-            pandas.DataFrame.compare,
-            other=other,
-            align_axis=align_axis,
-            keep_shape=keep_shape,
-            keep_equal=keep_equal,
+        if not isinstance(other, DataFrame):
+            raise TypeError(f"Cannot compare DataFrame to {type(other)}")
+        other = self._validate_other(other, 0, compare_index=True)
+        return self.__constructor__(
+            query_compiler=self._query_compiler.compare(
+                other,
+                align_axis=align_axis,
+                keep_shape=keep_shape,
+                keep_equal=keep_equal,
+            )
         )
 
     def corr(self, method="pearson", min_periods=1):

modin/pandas/series.py

@@ -482,13 +482,21 @@ def compare(
         keep_shape: bool = False,
         keep_equal: bool = False,
     ):
-        return self._default_to_pandas(
-            pandas.Series.compare,
-            other=other,
+        if not isinstance(other, Series):
+            raise TypeError(f"Cannot compare Series to {type(other)}")
+        result = self.to_frame().compare(
+            other.to_frame(),
             align_axis=align_axis,
             keep_shape=keep_shape,
             keep_equal=keep_equal,
         )
+        if align_axis == "columns" or align_axis == 1:
+            # Pandas.DataFrame.Compare returns a dataframe with a multidimensional index object as the
+            # columns so we have to change column object back.
+            result.columns = pandas.Index(["self", "other"])
+        else:
+            result = result.squeeze().rename(None)
+        return result
 
     def corr(self, other, method="pearson", min_periods=None):
         if method == "pearson":

modin/pandas/test/dataframe/test_join_sort.py

@@ -511,3 +511,43 @@ def test_where():
     pandas_result = pandas_df.where(pandas_df < 2, True)
     modin_result = modin_df.where(modin_df < 2, True)
     assert all((to_pandas(modin_result) == pandas_result).all())
+
+
+@pytest.mark.parametrize("align_axis", ["index", "columns"])
+@pytest.mark.parametrize("keep_shape", [False, True])
+@pytest.mark.parametrize("keep_equal", [False, True])
+def test_compare(align_axis, keep_shape, keep_equal):
+    kwargs = {
+        "align_axis": align_axis,
+        "keep_shape": keep_shape,
+        "keep_equal": keep_equal,
+    }
+    frame_data1 = random_state.randn(100, 10)
+    frame_data2 = random_state.randn(100, 10)
+    pandas_df = pandas.DataFrame(frame_data1, columns=list("abcdefghij"))
+    pandas_df2 = pandas.DataFrame(frame_data2, columns=list("abcdefghij"))
+    modin_df = pd.DataFrame(frame_data1, columns=list("abcdefghij"))
+    modin_df2 = pd.DataFrame(frame_data2, columns=list("abcdefghij"))
+
+    modin_result = modin_df.compare(modin_df2, **kwargs)
+    pandas_result = pandas_df.compare(pandas_df2, **kwargs)
+    assert to_pandas(modin_result).equals(pandas_result)
+
+    modin_result = modin_df2.compare(modin_df, **kwargs)
+    pandas_result = pandas_df2.compare(pandas_df, **kwargs)
+    assert to_pandas(modin_result).equals(pandas_result)
+
+    series_data1 = ["a", "b", "c", "d", "e"]
+    series_data2 = ["a", "a", "c", "b", "e"]
+    pandas_series1 = pandas.Series(series_data1)
+    pandas_series2 = pandas.Series(series_data2)
+    modin_series1 = pd.Series(series_data1)
+    modin_series2 = pd.Series(series_data2)
+
+    modin_result = modin_series1.compare(modin_series2, **kwargs)
+    pandas_result = pandas_series1.compare(pandas_series2, **kwargs)
+    assert to_pandas(modin_result).equals(pandas_result)
+
+    modin_result = modin_series2.compare(modin_series1, **kwargs)
+    pandas_result = pandas_series2.compare(pandas_series1, **kwargs)
+    assert to_pandas(modin_result).equals(pandas_result)