BUG/REF: Use lru_cache instead of NUMBA_FUNC_CACHE (pandas-dev#46086)

doc/source/whatsnew/v1.5.0.rst

@@ -383,6 +383,8 @@ Groupby/resample/rolling
 - Bug in :meth:`DataFrame.resample` ignoring ``closed="right"`` on :class:`TimedeltaIndex` (:issue:`45414`)
 - Bug in :meth:`.DataFrameGroupBy.transform` fails when ``func="size"`` and the input DataFrame has multiple columns (:issue:`27469`)
 - Bug in :meth:`.DataFrameGroupBy.size` and :meth:`.DataFrameGroupBy.transform` with ``func="size"`` produced incorrect results when ``axis=1`` (:issue:`45715`)
+- Bug in :meth:`.ExponentialMovingWindow.mean` with ``axis=1`` and ``engine='numba'`` when the :class:`DataFrame` has more columns than rows (:issue:`46086`)
+- Bug when using ``engine="numba"`` would return the same jitted function when modifying ``engine_kwargs`` (:issue:`46086`)
 - Bug in :meth:`.DataFrameGroupby.transform` fails when ``axis=1`` and ``func`` is ``"first"`` or ``"last"`` (:issue:`45986`)
 
 Reshaping

pandas/core/_numba/executor.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import functools
 from typing import (
     TYPE_CHECKING,
     Callable,
@@ -10,16 +11,13 @@
 from pandas._typing import Scalar
 from pandas.compat._optional import import_optional_dependency
 
-from pandas.core.util.numba_ import (
-    NUMBA_FUNC_CACHE,
-    get_jit_arguments,
-)
-
 
+@functools.lru_cache(maxsize=None)
 def generate_shared_aggregator(
     func: Callable[..., Scalar],
-    engine_kwargs: dict[str, bool] | None,
-    cache_key_str: str,
+    nopython: bool,
+    nogil: bool,
+    parallel: bool,
 ):
     """
     Generate a Numba function that loops over the columns 2D object and applies
@@ -29,22 +27,17 @@ def generate_shared_aggregator(
     ----------
     func : function
         aggregation function to be applied to each column
-    engine_kwargs : dict
-        dictionary of arguments to be passed into numba.jit
-    cache_key_str: str
-        string to access the compiled function of the form
-        <caller_type>_<aggregation_type> e.g. rolling_mean, groupby_mean
+    nopython : bool
+        nopython to be passed into numba.jit
+    nogil : bool
+        nogil to be passed into numba.jit
+    parallel : bool
+        parallel to be passed into numba.jit
 
     Returns
     -------
     Numba function
     """
-    nopython, nogil, parallel = get_jit_arguments(engine_kwargs, None)
-
-    cache_key = (func, cache_key_str)
-    if cache_key in NUMBA_FUNC_CACHE:
-        return NUMBA_FUNC_CACHE[cache_key]
-
     if TYPE_CHECKING:
         import numba
     else:

pandas/core/groupby/groupby.py

@@ -114,7 +114,7 @@ class providing the base-class of operations.
 from pandas.core.series import Series
 from pandas.core.sorting import get_group_index_sorter
 from pandas.core.util.numba_ import (
-    NUMBA_FUNC_CACHE,
+    get_jit_arguments,
     maybe_use_numba,
 )
 
@@ -1247,11 +1247,7 @@ def _resolve_numeric_only(self, numeric_only: bool | lib.NoDefault) -> bool:
     # numba
 
     @final
-    def _numba_prep(self, func, data):
-        if not callable(func):
-            raise NotImplementedError(
-                "Numba engine can only be used with a single function."
-            )
+    def _numba_prep(self, data):
         ids, _, ngroups = self.grouper.group_info
         sorted_index = get_group_index_sorter(ids, ngroups)
         sorted_ids = algorithms.take_nd(ids, sorted_index, allow_fill=False)
@@ -1271,7 +1267,6 @@ def _numba_agg_general(
         self,
         func: Callable,
         engine_kwargs: dict[str, bool] | None,
-        numba_cache_key_str: str,
         *aggregator_args,
     ):
         """
@@ -1288,16 +1283,12 @@ def _numba_agg_general(
         with self._group_selection_context():
             data = self._selected_obj
         df = data if data.ndim == 2 else data.to_frame()
-        starts, ends, sorted_index, sorted_data = self._numba_prep(func, df)
+        starts, ends, sorted_index, sorted_data = self._numba_prep(df)
         aggregator = executor.generate_shared_aggregator(
-            func, engine_kwargs, numba_cache_key_str
+            func, **get_jit_arguments(engine_kwargs)
         )
         result = aggregator(sorted_data, starts, ends, 0, *aggregator_args)
 
-        cache_key = (func, numba_cache_key_str)
-        if cache_key not in NUMBA_FUNC_CACHE:
-            NUMBA_FUNC_CACHE[cache_key] = aggregator
-
         index = self.grouper.result_index
         if data.ndim == 1:
             result_kwargs = {"name": data.name}
@@ -1315,10 +1306,10 @@ def _transform_with_numba(self, data, func, *args, engine_kwargs=None, **kwargs)
         to generate the indices of each group in the sorted data and then passes the
         data and indices into a Numba jitted function.
         """
-        starts, ends, sorted_index, sorted_data = self._numba_prep(func, data)
-
+        starts, ends, sorted_index, sorted_data = self._numba_prep(data)
+        numba_.validate_udf(func)
         numba_transform_func = numba_.generate_numba_transform_func(
-            kwargs, func, engine_kwargs
+            func, **get_jit_arguments(engine_kwargs, kwargs)
         )
         result = numba_transform_func(
             sorted_data,
@@ -1328,11 +1319,6 @@ def _transform_with_numba(self, data, func, *args, engine_kwargs=None, **kwargs)
             len(data.columns),
             *args,
         )
-
-        cache_key = (func, "groupby_transform")
-        if cache_key not in NUMBA_FUNC_CACHE:
-            NUMBA_FUNC_CACHE[cache_key] = numba_transform_func
-
         # result values needs to be resorted to their original positions since we
         # evaluated the data sorted by group
         return result.take(np.argsort(sorted_index), axis=0)
@@ -1346,9 +1332,11 @@ def _aggregate_with_numba(self, data, func, *args, engine_kwargs=None, **kwargs)
         to generate the indices of each group in the sorted data and then passes the
         data and indices into a Numba jitted function.
         """
-        starts, ends, sorted_index, sorted_data = self._numba_prep(func, data)
-
-        numba_agg_func = numba_.generate_numba_agg_func(kwargs, func, engine_kwargs)
+        starts, ends, sorted_index, sorted_data = self._numba_prep(data)
+        numba_.validate_udf(func)
+        numba_agg_func = numba_.generate_numba_agg_func(
+            func, **get_jit_arguments(engine_kwargs, kwargs)
+        )
         result = numba_agg_func(
             sorted_data,
             sorted_index,
@@ -1357,11 +1345,6 @@ def _aggregate_with_numba(self, data, func, *args, engine_kwargs=None, **kwargs)
             len(data.columns),
             *args,
         )
-
-        cache_key = (func, "groupby_agg")
-        if cache_key not in NUMBA_FUNC_CACHE:
-            NUMBA_FUNC_CACHE[cache_key] = numba_agg_func
-
         return result
 
     # -----------------------------------------------------------------
@@ -1947,7 +1930,7 @@ def mean(
         if maybe_use_numba(engine):
             from pandas.core._numba.kernels import sliding_mean
 
-            return self._numba_agg_general(sliding_mean, engine_kwargs, "groupby_mean")
+            return self._numba_agg_general(sliding_mean, engine_kwargs)
         else:
             result = self._cython_agg_general(
                 "mean",
@@ -2029,9 +2012,7 @@ def std(
         if maybe_use_numba(engine):
             from pandas.core._numba.kernels import sliding_var
 
-            return np.sqrt(
-                self._numba_agg_general(sliding_var, engine_kwargs, "groupby_std", ddof)
-            )
+            return np.sqrt(self._numba_agg_general(sliding_var, engine_kwargs, ddof))
         else:
             return self._get_cythonized_result(
                 libgroupby.group_var,
@@ -2085,9 +2066,7 @@ def var(
         if maybe_use_numba(engine):
             from pandas.core._numba.kernels import sliding_var
 
-            return self._numba_agg_general(
-                sliding_var, engine_kwargs, "groupby_var", ddof
-            )
+            return self._numba_agg_general(sliding_var, engine_kwargs, ddof)
         else:
             if ddof == 1:
                 numeric_only = self._resolve_numeric_only(lib.no_default)
@@ -2180,7 +2159,6 @@ def sum(
             return self._numba_agg_general(
                 sliding_sum,
                 engine_kwargs,
-                "groupby_sum",
             )
         else:
             numeric_only = self._resolve_numeric_only(numeric_only)
@@ -2221,9 +2199,7 @@ def min(
         if maybe_use_numba(engine):
             from pandas.core._numba.kernels import sliding_min_max
 
-            return self._numba_agg_general(
-                sliding_min_max, engine_kwargs, "groupby_min", False
-            )
+            return self._numba_agg_general(sliding_min_max, engine_kwargs, False)
         else:
             return self._agg_general(
                 numeric_only=numeric_only,
@@ -2244,9 +2220,7 @@ def max(
         if maybe_use_numba(engine):
             from pandas.core._numba.kernels import sliding_min_max
 
-            return self._numba_agg_general(
-                sliding_min_max, engine_kwargs, "groupby_max", True
-            )
+            return self._numba_agg_general(sliding_min_max, engine_kwargs, True)
         else:
             return self._agg_general(
                 numeric_only=numeric_only,

pandas/core/groupby/numba_.py

@@ -1,6 +1,7 @@
 """Common utilities for Numba operations with groupby ops"""
 from __future__ import annotations
 
+import functools
 import inspect
 from typing import (
     TYPE_CHECKING,
@@ -14,9 +15,7 @@
 from pandas.compat._optional import import_optional_dependency
 
 from pandas.core.util.numba_ import (
-    NUMBA_FUNC_CACHE,
     NumbaUtilError,
-    get_jit_arguments,
     jit_user_function,
 )
 
@@ -43,6 +42,10 @@ def f(values, index, ...):
     ------
     NumbaUtilError
     """
+    if not callable(func):
+        raise NotImplementedError(
+            "Numba engine can only be used with a single function."
+        )
     udf_signature = list(inspect.signature(func).parameters.keys())
     expected_args = ["values", "index"]
     min_number_args = len(expected_args)
@@ -56,10 +59,12 @@ def f(values, index, ...):
         )
 
 
+@functools.lru_cache(maxsize=None)
 def generate_numba_agg_func(
-    kwargs: dict[str, Any],
     func: Callable[..., Scalar],
-    engine_kwargs: dict[str, bool] | None,
+    nopython: bool,
+    nogil: bool,
+    parallel: bool,
 ) -> Callable[[np.ndarray, np.ndarray, np.ndarray, np.ndarray, int, Any], np.ndarray]:
     """
     Generate a numba jitted agg function specified by values from engine_kwargs.
@@ -72,24 +77,19 @@ def generate_numba_agg_func(
 
     Parameters
     ----------
-    kwargs : dict
-        **kwargs to be passed into the function
     func : function
-        function to be applied to each window and will be JITed
-    engine_kwargs : dict
-        dictionary of arguments to be passed into numba.jit
+        function to be applied to each group and will be JITed
+    nopython : bool
+        nopython to be passed into numba.jit
+    nogil : bool
+        nogil to be passed into numba.jit
+    parallel : bool
+        parallel to be passed into numba.jit
 
     Returns
     -------
     Numba function
     """
-    nopython, nogil, parallel = get_jit_arguments(engine_kwargs, kwargs)
-
-    validate_udf(func)
-    cache_key = (func, "groupby_agg")
-    if cache_key in NUMBA_FUNC_CACHE:
-        return NUMBA_FUNC_CACHE[cache_key]
-
     numba_func = jit_user_function(func, nopython, nogil, parallel)
     if TYPE_CHECKING:
         import numba
@@ -120,10 +120,12 @@ def group_agg(
     return group_agg
 
 
+@functools.lru_cache(maxsize=None)
 def generate_numba_transform_func(
-    kwargs: dict[str, Any],
     func: Callable[..., np.ndarray],
-    engine_kwargs: dict[str, bool] | None,
+    nopython: bool,
+    nogil: bool,
+    parallel: bool,
 ) -> Callable[[np.ndarray, np.ndarray, np.ndarray, np.ndarray, int, Any], np.ndarray]:
     """
     Generate a numba jitted transform function specified by values from engine_kwargs.
@@ -136,24 +138,19 @@ def generate_numba_transform_func(
 
     Parameters
     ----------
-    kwargs : dict
-        **kwargs to be passed into the function
     func : function
         function to be applied to each window and will be JITed
-    engine_kwargs : dict
-        dictionary of arguments to be passed into numba.jit
+    nopython : bool
+        nopython to be passed into numba.jit
+    nogil : bool
+        nogil to be passed into numba.jit
+    parallel : bool
+        parallel to be passed into numba.jit
 
     Returns
     -------
     Numba function
     """
-    nopython, nogil, parallel = get_jit_arguments(engine_kwargs, kwargs)
-
-    validate_udf(func)
-    cache_key = (func, "groupby_transform")
-    if cache_key in NUMBA_FUNC_CACHE:
-        return NUMBA_FUNC_CACHE[cache_key]
-
     numba_func = jit_user_function(func, nopython, nogil, parallel)
     if TYPE_CHECKING:
         import numba

pandas/core/util/numba_.py

@@ -13,7 +13,6 @@
 from pandas.errors import NumbaUtilError
 
 GLOBAL_USE_NUMBA: bool = False
-NUMBA_FUNC_CACHE: dict[tuple[Callable, str], Callable] = {}
 
 
 def maybe_use_numba(engine: str | None) -> bool:
@@ -30,7 +29,7 @@ def set_use_numba(enable: bool = False) -> None:
 
 def get_jit_arguments(
     engine_kwargs: dict[str, bool] | None = None, kwargs: dict | None = None
-) -> tuple[bool, bool, bool]:
+) -> dict[str, bool]:
     """
     Return arguments to pass to numba.JIT, falling back on pandas default JIT settings.
 
@@ -43,7 +42,7 @@ def get_jit_arguments(
 
     Returns
     -------
-    (bool, bool, bool)
+    dict[str, bool]
         nopython, nogil, parallel
 
     Raises
@@ -61,7 +60,7 @@ def get_jit_arguments(
         )
     nogil = engine_kwargs.get("nogil", False)
     parallel = engine_kwargs.get("parallel", False)
-    return nopython, nogil, parallel
+    return {"nopython": nopython, "nogil": nogil, "parallel": parallel}
 
 
 def jit_user_function(