From 4b5db3adde2b6b1e3a2132a9593e969b7d3a369a Mon Sep 17 00:00:00 2001
From: jbrockmendel <jbrockmendel@gmail.com>
Date: Mon, 14 Oct 2019 12:24:59 -0700
Subject: [PATCH 1/4] REF: remove need for eval_kwargs

---
 pandas/core/computation/expressions.py | 13 ++++----
 pandas/core/ops/__init__.py            | 41 ++------------------------
 pandas/core/ops/array_ops.py           | 19 +++++-------
 3 files changed, 15 insertions(+), 58 deletions(-)

diff --git a/pandas/core/computation/expressions.py b/pandas/core/computation/expressions.py
index 46bc762e1a0b3..77999d2c166fd 100644
--- a/pandas/core/computation/expressions.py
+++ b/pandas/core/computation/expressions.py
@@ -62,9 +62,8 @@ def set_numexpr_threads(n=None):
         ne.set_num_threads(n)
 
 
-def _evaluate_standard(op, op_str, a, b, reversed=False):
+def _evaluate_standard(op, op_str, a, b):
     """ standard evaluation """
-    # `reversed` kwarg is included for compatibility with _evaluate_numexpr
     if _TEST_MODE:
         _store_test_result(False)
     with np.errstate(all="ignore"):
@@ -97,11 +96,12 @@ def _can_use_numexpr(op, op_str, a, b, dtype_check):
     return False
 
 
-def _evaluate_numexpr(op, op_str, a, b, reversed=False):
+def _evaluate_numexpr(op, op_str, a, b):
     result = None
 
     if _can_use_numexpr(op, op_str, a, b, "evaluate"):
-        if reversed:
+        is_reversed = op.__name__.strip("_").startswith("r")
+        if is_reversed:
             # we were originally called by a reversed op method
             a, b = b, a
 
@@ -190,7 +190,7 @@ def _bool_arith_check(
     return True
 
 
-def evaluate(op, op_str, a, b, use_numexpr=True, reversed=False):
+def evaluate(op, op_str, a, b, use_numexpr=True):
     """
     Evaluate and return the expression of the op on a and b.
 
@@ -203,12 +203,11 @@ def evaluate(op, op_str, a, b, use_numexpr=True, reversed=False):
     b : right operand
     use_numexpr : bool, default True
         Whether to try to use numexpr.
-    reversed : bool, default False
     """
 
     use_numexpr = use_numexpr and _bool_arith_check(op_str, a, b)
     if use_numexpr:
-        return _evaluate(op, op_str, a, b, reversed=reversed)
+        return _evaluate(op, op_str, a, b)
     return _evaluate_standard(op, op_str, a, b)
 
 
diff --git a/pandas/core/ops/__init__.py b/pandas/core/ops/__init__.py
index 398fa9b0c1fc0..bcd4293e7bb0d 100644
--- a/pandas/core/ops/__init__.py
+++ b/pandas/core/ops/__init__.py
@@ -181,41 +181,6 @@ def maybe_upcast_for_op(obj, shape: Tuple[int, ...]):
 # -----------------------------------------------------------------------------
 
 
-def _gen_eval_kwargs(name):
-    """
-    Find the keyword arguments to pass to numexpr for the given operation.
-
-    Parameters
-    ----------
-    name : str
-
-    Returns
-    -------
-    eval_kwargs : dict
-
-    Examples
-    --------
-    >>> _gen_eval_kwargs("__add__")
-    {}
-
-    >>> _gen_eval_kwargs("rtruediv")
-    {'reversed': True, 'truediv': True}
-    """
-    kwargs = {}
-
-    # Series appear to only pass __add__, __radd__, ...
-    # but DataFrame gets both these dunder names _and_ non-dunder names
-    # add, radd, ...
-    name = name.replace("__", "")
-
-    if name.startswith("r"):
-        if name not in ["radd", "rand", "ror", "rxor"]:
-            # Exclude commutative operations
-            kwargs["reversed"] = True
-
-    return kwargs
-
-
 def _get_frame_op_default_axis(name):
     """
     Only DataFrame cares about default_axis, specifically:
@@ -487,7 +452,6 @@ def _arith_method_SERIES(cls, op, special):
     """
     str_rep = _get_opstr(op)
     op_name = _get_op_name(op, special)
-    eval_kwargs = _gen_eval_kwargs(op_name)
 
     def wrapper(left, right):
         if isinstance(right, ABCDataFrame):
@@ -497,7 +461,7 @@ def wrapper(left, right):
         res_name = get_op_result_name(left, right)
 
         lvalues = extract_array(left, extract_numpy=True)
-        result = arithmetic_op(lvalues, right, op, str_rep, eval_kwargs)
+        result = arithmetic_op(lvalues, right, op, str_rep)
 
         return _construct_result(left, result, index=left.index, name=res_name)
 
@@ -688,10 +652,9 @@ def to_series(right):
 def _arith_method_FRAME(cls, op, special):
     str_rep = _get_opstr(op)
     op_name = _get_op_name(op, special)
-    eval_kwargs = _gen_eval_kwargs(op_name)
     default_axis = _get_frame_op_default_axis(op_name)
 
-    na_op = define_na_arithmetic_op(op, str_rep, eval_kwargs)
+    na_op = define_na_arithmetic_op(op, str_rep)
     is_logical = str_rep in ["&", "|", "^"]
 
     if op_name in _op_descriptions:
diff --git a/pandas/core/ops/array_ops.py b/pandas/core/ops/array_ops.py
index 8c9a4b94446c0..414e241af7bbd 100644
--- a/pandas/core/ops/array_ops.py
+++ b/pandas/core/ops/array_ops.py
@@ -3,7 +3,7 @@
 ExtensionArrays.
 """
 import operator
-from typing import Any, Dict, Union
+from typing import Any, Union
 
 import numpy as np
 
@@ -118,14 +118,14 @@ def masked_arith_op(x, y, op):
     return result
 
 
-def define_na_arithmetic_op(op, str_rep: str, eval_kwargs):
+def define_na_arithmetic_op(op, str_rep: str):
     def na_op(x, y):
-        return na_arithmetic_op(x, y, op, str_rep, eval_kwargs)
+        return na_arithmetic_op(x, y, op, str_rep)
 
     return na_op
 
 
-def na_arithmetic_op(left, right, op, str_rep: str, eval_kwargs):
+def na_arithmetic_op(left, right, op, str_rep: str):
     """
     Return the result of evaluating op on the passed in values.
 
@@ -136,7 +136,6 @@ def na_arithmetic_op(left, right, op, str_rep: str, eval_kwargs):
     left : np.ndarray
     right : np.ndarray or scalar
     str_rep : str or None
-    eval_kwargs : kwargs to pass to expressions
 
     Returns
     -------
@@ -149,7 +148,7 @@ def na_arithmetic_op(left, right, op, str_rep: str, eval_kwargs):
     import pandas.core.computation.expressions as expressions
 
     try:
-        result = expressions.evaluate(op, str_rep, left, right, **eval_kwargs)
+        result = expressions.evaluate(op, str_rep, left, right)
     except TypeError:
         result = masked_arith_op(left, right, op)
 
@@ -157,11 +156,7 @@ def na_arithmetic_op(left, right, op, str_rep: str, eval_kwargs):
 
 
 def arithmetic_op(
-    left: Union[np.ndarray, ABCExtensionArray],
-    right: Any,
-    op,
-    str_rep: str,
-    eval_kwargs: Dict[str, bool],
+    left: Union[np.ndarray, ABCExtensionArray], right: Any, op, str_rep: str
 ):
     """
     Evaluate an arithmetic operation `+`, `-`, `*`, `/`, `//`, `%`, `**`, ...
@@ -212,7 +207,7 @@ def arithmetic_op(
 
     else:
         with np.errstate(all="ignore"):
-            res_values = na_arithmetic_op(lvalues, rvalues, op, str_rep, eval_kwargs)
+            res_values = na_arithmetic_op(lvalues, rvalues, op, str_rep)
 
     return res_values
 

From 688bb0427641ea786ea2244d11f7b4b8966a9adf Mon Sep 17 00:00:00 2001
From: jbrockmendel <jbrockmendel@gmail.com>
Date: Thu, 14 Nov 2019 07:40:14 -0800
Subject: [PATCH 2/4] fixup: missed in rebase

---
 pandas/core/ops/array_ops.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/pandas/core/ops/array_ops.py b/pandas/core/ops/array_ops.py
index 1d22b3b55b48c..6787ce61c3ae8 100644
--- a/pandas/core/ops/array_ops.py
+++ b/pandas/core/ops/array_ops.py
@@ -160,7 +160,6 @@ def arithmetic_op(
     right: Any,
     op,
     str_rep: str,
-    eval_kwargs: Mapping[str, bool],
 ):
     """
     Evaluate an arithmetic operation `+`, `-`, `*`, `/`, `//`, `%`, `**`, ...

From a512d4f1f9cfb6d49a080d16b7c305296865dc6e Mon Sep 17 00:00:00 2001
From: jbrockmendel <jbrockmendel@gmail.com>
Date: Thu, 14 Nov 2019 09:31:48 -0800
Subject: [PATCH 3/4] CLN: fixup unused importt

---
 pandas/core/ops/array_ops.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/ops/array_ops.py b/pandas/core/ops/array_ops.py
index 6787ce61c3ae8..e33883fabdb33 100644
--- a/pandas/core/ops/array_ops.py
+++ b/pandas/core/ops/array_ops.py
@@ -3,7 +3,7 @@
 ExtensionArrays.
 """
 import operator
-from typing import Any, Mapping, Union
+from typing import Any, Union
 
 import numpy as np
 

From f68d50fd1fad5ebc7fd2cd4291105328e4f15b60 Mon Sep 17 00:00:00 2001
From: jbrockmendel <jbrockmendel@gmail.com>
Date: Thu, 14 Nov 2019 10:38:36 -0800
Subject: [PATCH 4/4] blackify

---
 pandas/core/ops/array_ops.py | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/pandas/core/ops/array_ops.py b/pandas/core/ops/array_ops.py
index e33883fabdb33..414e241af7bbd 100644
--- a/pandas/core/ops/array_ops.py
+++ b/pandas/core/ops/array_ops.py
@@ -156,10 +156,7 @@ def na_arithmetic_op(left, right, op, str_rep: str):
 
 
 def arithmetic_op(
-    left: Union[np.ndarray, ABCExtensionArray],
-    right: Any,
-    op,
-    str_rep: str,
+    left: Union[np.ndarray, ABCExtensionArray], right: Any, op, str_rep: str
 ):
     """
     Evaluate an arithmetic operation `+`, `-`, `*`, `/`, `//`, `%`, `**`, ...