From: Raymond Hettinger <python@rcn.com>
Date: Mon, 26 May 2014 00:40:25 +0000 (-0700)
Subject: Issue 13355:  Make random.triangular degrade gracefully when low == high.
X-Git-Tag: v2.7.8~37^2~83
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=92df7529cb6c863d0fcd3247829b24833f62e285;p=thirdparty%2FPython%2Fcpython.git

Issue 13355:  Make random.triangular degrade gracefully when low == high.
---

diff --git a/Lib/random.py b/Lib/random.py
index e89fae663a7b..3f96a3770b4e 100644
--- a/Lib/random.py
+++ b/Lib/random.py
@@ -371,7 +371,10 @@ class Random(_random.Random):
 
         """
         u = self.random()
-        c = 0.5 if mode is None else (mode - low) / (high - low)
+        try:
+            c = 0.5 if mode is None else (mode - low) / (high - low)
+        except ZeroDivisionError:
+            return low
         if u > c:
             u = 1.0 - u
             c = 1.0 - c
diff --git a/Lib/test/test_random.py b/Lib/test/test_random.py
index ba447ee57aa5..1a5a86b9e23c 100644
--- a/Lib/test/test_random.py
+++ b/Lib/test/test_random.py
@@ -541,7 +541,7 @@ class TestDistributions(unittest.TestCase):
         for variate, args, expected in [
                 (g.uniform, (10.0, 10.0), 10.0),
                 (g.triangular, (10.0, 10.0), 10.0),
-                #(g.triangular, (10.0, 10.0, 10.0), 10.0),
+                (g.triangular, (10.0, 10.0, 10.0), 10.0),
                 (g.expovariate, (float('inf'),), 0.0),
                 (g.vonmisesvariate, (3.0, float('inf')), 3.0),
                 (g.gauss, (10.0, 0.0), 10.0),
diff --git a/Misc/NEWS b/Misc/NEWS
index d46d1d30636c..04e9221d9440 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -23,6 +23,9 @@ Tests
 
 - Issue #19925: Added tests for the spwd module. Original patch by Vajrasky Kok.
 
+- Issue #13355: random.triangular() no longer fails with a ZeroDivisionError
+  when low equals high.
+
 - Issue #21522: Added Tkinter tests for Listbox.itemconfigure(),
   PanedWindow.paneconfigure(), and Menu.entryconfigure().