Repository: alteryx/evalml (python)

Issue:
Holdout data splitter creates NaN values with multiseries datasets

Pull request description:
Update split_data to call split_multiseries_data
Closes #4311

Patch:
diff --git a/docs/source/release_notes.rst b/docs/source/release_notes.rst
index 54c565a9..efcfb028 100644
--- a/docs/source/release_notes.rst
+++ b/docs/source/release_notes.rst
@@ -10,6 +10,7 @@ Release Notes
         * Extended TimeSeriesRegularizer to support multiseries :pr:`4303`
     * Fixes
     * Changes
+        * Updated ``split_data`` to call ``split_multiseries_data`` when passed stacked multiseries data :pr:`4312`
     * Documentation Changes
         * Removed LightGBM's excessive amount of warnings :pr:`4308`
     * Testing Changes
diff --git a/evalml/preprocessing/utils.py b/evalml/preprocessing/utils.py
index 6e7c2036..dc17e75e 100644
--- a/evalml/preprocessing/utils.py
+++ b/evalml/preprocessing/utils.py
@@ -4,7 +4,12 @@ from sklearn.model_selection import ShuffleSplit, StratifiedShuffleSplit
 
 from evalml.pipelines.utils import stack_data, stack_X, unstack_multiseries
 from evalml.preprocessing.data_splitters import TrainingValidationSplit
-from evalml.problem_types import is_classification, is_regression, is_time_series
+from evalml.problem_types import (
+    is_classification,
+    is_multiseries,
+    is_regression,
+    is_time_series,
+)
 from evalml.utils import infer_feature_types
 
 
@@ -118,6 +123,9 @@ def split_data(
     Returns:
         pd.DataFrame, pd.DataFrame, pd.Series, pd.Series: Feature and target data each split into train and test sets.
 
+    Raises:
+        ValueError: If the problem_configuration is missing or does not contain both a time_index and series_id for multiseries problems.
+
     Examples:
         >>> X = pd.DataFrame([1, 2, 3, 4, 5, 6], columns=["First"])
         >>> y = pd.Series([8, 9, 10, 11, 12, 13])
@@ -144,6 +152,27 @@ def split_data(
         1    9
         dtype: int64
     """
+    if is_multiseries(problem_type) and isinstance(y, pd.Series):
+        if problem_configuration is None:
+            raise ValueError(
+                "split_data requires problem_configuration for multiseries problems",
+            )
+        series_id = problem_configuration.get("series_id")
+        time_index = problem_configuration.get("time_index")
+        if series_id is None or time_index is None:
+            raise ValueError(
+                "split_data needs both series_id and time_index values in the problem_configuration to split multiseries data",
+            )
+        return split_multiseries_data(
+            X,
+            y,
+            series_id,
+            time_index,
+            problem_configuration=problem_configuration,
+            test_size=test_size,
+            random_seed=random_seed,
+        )
+
     X = infer_feature_types(X)
     y = infer_feature_types(y)
 


Test patch:
diff --git a/evalml/tests/preprocessing_tests/test_split_data.py b/evalml/tests/preprocessing_tests/test_split_data.py
index cbb8c941..f5e494d5 100644
--- a/evalml/tests/preprocessing_tests/test_split_data.py
+++ b/evalml/tests/preprocessing_tests/test_split_data.py
@@ -6,6 +6,7 @@ from evalml.problem_types import (
     ProblemTypes,
     is_binary,
     is_multiclass,
+    is_multiseries,
     is_regression,
     is_time_series,
 )
@@ -19,6 +20,7 @@ def test_split_data(
     X_y_binary,
     X_y_multi,
     X_y_regression,
+    multiseries_ts_data_unstacked,
     make_data_type,
 ):
     if is_binary(problem_type):
@@ -30,6 +32,8 @@ def test_split_data(
     problem_configuration = None
     if is_time_series(problem_type):
         problem_configuration = {"gap": 1, "max_delay": 7, "time_index": "date"}
+        if is_multiseries(problem_type):
+            X, y = multiseries_ts_data_unstacked
 
     X = make_data_type(data_type, X)
     y = make_data_type(data_type, y)
@@ -50,17 +54,28 @@ def test_split_data(
     assert len(y_test) == test_size
     assert isinstance(X_train, pd.DataFrame)
     assert isinstance(X_test, pd.DataFrame)
-    assert isinstance(y_train, pd.Series)
-    assert isinstance(y_test, pd.Series)
+    if not is_multiseries(problem_type):
+        assert isinstance(y_train, pd.Series)
+        assert isinstance(y_test, pd.Series)
+    else:
+        assert isinstance(y_train, pd.DataFrame)
+        assert isinstance(y_test, pd.DataFrame)
+        pd.testing.assert_frame_equal(X_test, X[int(train_size) :], check_dtype=False)
+        pd.testing.assert_frame_equal(y_test, y[int(train_size) :], check_dtype=False)
 
-    if is_time_series(problem_type):
+    if is_time_series(problem_type) and not is_multiseries(problem_type):
         pd.testing.assert_frame_equal(X_test, X[int(train_size) :], check_dtype=False)
         pd.testing.assert_series_equal(y_test, y[int(train_size) :], check_dtype=False)
 
 
 @pytest.mark.parametrize("problem_type", ProblemTypes.all_problem_types)
 @pytest.mark.parametrize("data_type", ["np", "pd", "ww"])
-def test_split_data_defaults(problem_type, data_type, get_test_data_from_configuration):
+def test_split_data_defaults(
+    problem_type,
+    data_type,
+    get_test_data_from_configuration,
+    multiseries_ts_data_unstacked,
+):
     X, y = get_test_data_from_configuration(
         data_type,
         problem_type,
@@ -71,6 +86,8 @@ def test_split_data_defaults(problem_type, data_type, get_test_data_from_configu
     problem_configuration = None
     if is_time_series(problem_type):
         problem_configuration = {"gap": 1, "max_delay": 7, "time_index": "date"}
+        if is_multiseries(problem_type):
+            X, y = multiseries_ts_data_unstacked
         test_pct = 0.1
     else:
         test_pct = 0.2
@@ -92,7 +109,18 @@ def test_split_data_defaults(problem_type, data_type, get_test_data_from_configu
             X = pd.DataFrame(X)
             y = pd.Series(y)
         pd.testing.assert_frame_equal(X_test, X[int(train_size) :], check_dtype=False)
-        pd.testing.assert_series_equal(y_test, y[int(train_size) :], check_dtype=False)
+        if not is_multiseries(problem_type):
+            pd.testing.assert_series_equal(
+                y_test,
+                y[int(train_size) :],
+                check_dtype=False,
+            )
+        else:
+            pd.testing.assert_frame_equal(
+                y_test,
+                y[int(train_size) :],
+                check_dtype=False,
+            )
 
 
 @pytest.mark.parametrize("test", ["fh_limitation", "no_fh_limitation"])
@@ -127,8 +155,33 @@ def test_split_data_ts(test, X_y_regression):
     assert len(y_test) == test_size
 
 
+def test_split_data_calls_multiseries_error(multiseries_ts_data_stacked):
+    X, y = multiseries_ts_data_stacked
+    with pytest.raises(
+        ValueError,
+        match="requires problem_configuration for multiseries",
+    ):
+        split_data(X, y, problem_type="multiseries time series regression")
+
+    with pytest.raises(
+        ValueError,
+        match="needs both series_id and time_index values in the problem_configuration",
+    ):
+        split_data(
+            X,
+            y,
+            problem_type="multiseries time series regression",
+            problem_configuration={"time_index": "date"},
+        )
+
+
 @pytest.mark.parametrize("no_features", [True, False])
-def test_split_multiseries_data(no_features, multiseries_ts_data_stacked):
+@pytest.mark.parametrize("splitting_function", ["split_data", "split_multiseries_data"])
+def test_split_multiseries_data(
+    no_features,
+    splitting_function,
+    multiseries_ts_data_stacked,
+):
     X, y = multiseries_ts_data_stacked
 
     if no_features:
@@ -137,12 +190,22 @@ def test_split_multiseries_data(no_features, multiseries_ts_data_stacked):
     X_train_expected, X_holdout_expected = X[:-10], X[-10:]
     y_train_expected, y_holdout_expected = y[:-10], y[-10:]
 
-    X_train, X_holdout, y_train, y_holdout = split_multiseries_data(
-        X,
-        y,
-        "series_id",
-        "date",
-    )
+    # Results should be identical whether split_multiseries_data is called through
+    # split_data or directly
+    if splitting_function == "split_data":
+        X_train, X_holdout, y_train, y_holdout = split_data(
+            X,
+            y,
+            problem_type="multiseries time series regression",
+            problem_configuration={"time_index": "date", "series_id": "series_id"},
+        )
+    else:
+        X_train, X_holdout, y_train, y_holdout = split_multiseries_data(
+            X,
+            y,
+            "series_id",
+            "date",
+        )
 
     pd.testing.assert_frame_equal(
         X_train.sort_index(axis=1),