From 70496de81cff7723eadc387e96833c098edaf386 Mon Sep 17 00:00:00 2001
From: Gui Miotto <guilherme.miotto@gmail.com>
Date: Wed, 18 Mar 2020 14:36:47 +0100
Subject: [PATCH 1/2] close #16717

---
 sklearn/decomposition/_kernel_pca.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sklearn/decomposition/_kernel_pca.py b/sklearn/decomposition/_kernel_pca.py
index b80935b4d4359..212686ae50d5a 100644
--- a/sklearn/decomposition/_kernel_pca.py
+++ b/sklearn/decomposition/_kernel_pca.py
@@ -216,7 +216,7 @@ def _fit_transform(self, K):
 
         # flip eigenvectors' sign to enforce deterministic output
         self.alphas_, _ = svd_flip(self.alphas_,
-                                   np.empty_like(self.alphas_).T)
+                                   np.zeros_like(self.alphas_).T)
 
         # sort eigenvectors in descending order
         indices = self.lambdas_.argsort()[::-1]

From 49aa2d9da1c392fe3dacd32e0efd4eaf7f063b72 Mon Sep 17 00:00:00 2001
From: Gui Miotto <guilherme.miotto@gmail.com>
Date: Thu, 19 Mar 2020 13:27:25 +0100
Subject: [PATCH 2/2] update whats_new

---
 doc/whats_new/v0.23.rst | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/doc/whats_new/v0.23.rst b/doc/whats_new/v0.23.rst
index d0c568956a353..6141dcce41609 100644
--- a/doc/whats_new/v0.23.rst
+++ b/doc/whats_new/v0.23.rst
@@ -146,6 +146,10 @@ Changelog
   applies the correct inverse transform to the transformed data. :pr:`16655`
   by :user:`Lewis Ball <lrjball>`.
 
+- |Fix| Fixed bug that was causing :class:`decomposition.KernelPCA` to sometimes
+  raise `invalid value encountered in multiply` during `fit`.
+  :pr:`16718` by :user:`Gui Miotto <gui-miotto>`.
+
 :mod:`sklearn.ensemble`
 .......................