From 03a8e0a1b9c59a3d32d49a0d6632a6d7abfa447a Mon Sep 17 00:00:00 2001
From: Peter Krusche <pkrusche@illumina.com>
Date: Wed, 5 Oct 2016 19:39:15 +0100
Subject: [PATCH] HAP-240 avoid division by zero

---
 src/python/Tools/ci.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/python/Tools/ci.py b/src/python/Tools/ci.py
index 175cfa6..1e4a1b4 100644
--- a/src/python/Tools/ci.py
+++ b/src/python/Tools/ci.py
@@ -23,6 +23,10 @@ def jeffreysCI(x, n, alpha=0.05):
     Brown, Cai and DasGupta: Interval Estimation for a Binomial Proportion.
     2001, doi:10.1214/ss/1009213286'''
 
+    # HAP-240 avoid division by zero
+    if n == 0:
+        return 0.0, 0.0, 1.0
+
     p = x / n
     beta = stats.distributions.beta(x+0.5, n-x+0.5)