From e77b7b98df233f72a9d50934a4bf5b93c163b482 Mon Sep 17 00:00:00 2001
From: John Kirkham <kirkhamj@janelia.hhmi.org>
Date: Thu, 21 Jan 2016 13:24:59 -0500
Subject: BUG: In `norm`, always cast non-floating point arrays to 64-bit
 floats. Otherwise, weird integer roundoff errors give faulty results in some
 cases.

---
 numpy/linalg/linalg.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/numpy/linalg/linalg.py b/numpy/linalg/linalg.py
index 9dc879d31..fe2031efb 100644
--- a/numpy/linalg/linalg.py
+++ b/numpy/linalg/linalg.py
@@ -2112,6 +2112,9 @@ def norm(x, ord=None, axis=None, keepdims=False):
     """
     x = asarray(x)
 
+    if not issubclass(x.dtype.type, inexact):
+        x = x.astype(float)
+
     # Immediately handle some default, simple, fast, and common cases.
     if axis is None:
         ndim = x.ndim
-- 
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