From b28e6d2256236871fb4e957d5fa63ac9ab05bd13 Mon Sep 17 00:00:00 2001
From: Sean Owen <sean.owen@databricks.com>
Date: Wed, 16 Jan 2019 17:15:57 -0600
Subject: [PATCH] Fix implementation of unary negation (__neg__) in Pyspark
 DenseVectors

---
 python/pyspark/ml/linalg/__init__.py    | 6 +++++-
 python/pyspark/mllib/linalg/__init__.py | 6 +++++-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/python/pyspark/ml/linalg/__init__.py b/python/pyspark/ml/linalg/__init__.py
index 2548fd0f50b33..9da983667be7d 100644
--- a/python/pyspark/ml/linalg/__init__.py
+++ b/python/pyspark/ml/linalg/__init__.py
@@ -270,6 +270,8 @@ class DenseVector(Vector):
     DenseVector([3.0, 2.0])
     >>> u % 2
     DenseVector([1.0, 0.0])
+    >>> -v
+    DenseVector([-1.0, -2.0])
     """
     def __init__(self, ar):
         if isinstance(ar, bytes):
@@ -436,6 +438,9 @@ def __hash__(self):
     def __getattr__(self, item):
         return getattr(self.array, item)
 
+    def __neg__(self):
+        return DenseVector(-self.array)
+
     def _delegate(op):
         def func(self, other):
             if isinstance(other, DenseVector):
@@ -443,7 +448,6 @@ def func(self, other):
             return DenseVector(getattr(self.array, op)(other))
         return func
 
-    __neg__ = _delegate("__neg__")
     __add__ = _delegate("__add__")
     __sub__ = _delegate("__sub__")
     __mul__ = _delegate("__mul__")
diff --git a/python/pyspark/mllib/linalg/__init__.py b/python/pyspark/mllib/linalg/__init__.py
index 4afd6666400b0..94a3e2af4d2d1 100644
--- a/python/pyspark/mllib/linalg/__init__.py
+++ b/python/pyspark/mllib/linalg/__init__.py
@@ -281,6 +281,8 @@ class DenseVector(Vector):
     DenseVector([3.0, 2.0])
     >>> u % 2
     DenseVector([1.0, 0.0])
+    >>> -v
+    DenseVector([-1.0, -2.0])
     """
     def __init__(self, ar):
         if isinstance(ar, bytes):
@@ -480,6 +482,9 @@ def __hash__(self):
     def __getattr__(self, item):
         return getattr(self.array, item)
 
+    def __neg__(self):
+        return DenseVector(-self.array)
+
     def _delegate(op):
         def func(self, other):
             if isinstance(other, DenseVector):
@@ -487,7 +492,6 @@ def func(self, other):
             return DenseVector(getattr(self.array, op)(other))
         return func
 
-    __neg__ = _delegate("__neg__")
     __add__ = _delegate("__add__")
     __sub__ = _delegate("__sub__")
     __mul__ = _delegate("__mul__")