From 17be0257a0ec05994ff6d2a2fea8edcd15b5dfc7 Mon Sep 17 00:00:00 2001
From: Patrick Shriwise <pshriwise@gmail.com>
Date: Tue, 5 Apr 2022 14:05:35 -0500
Subject: [PATCH] Correction to histogram cdf method

---
 openmc/stats/univariate.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/openmc/stats/univariate.py b/openmc/stats/univariate.py
index 3d99f8b8ce..7fc479e630 100644
--- a/openmc/stats/univariate.py
+++ b/openmc/stats/univariate.py
@@ -889,7 +889,7 @@ class Tabular(Univariate):
         x = np.asarray(self.x)
         p = np.asarray(self.p)
         if self.interpolation == 'histogram':
-            c[1:] = p * np.diff(x)
+            c[1:] = p[:-1] * np.diff(x)
         elif self.interpolation == 'linear-linear':
             c[1:] = 0.5 * (p[0:-1] + p[1:]) * np.diff(x)
         return np.cumsum(c)