From 1054134bd9e8796861500e4d714980b0e2cf28bf Mon Sep 17 00:00:00 2001
From: Eddie Hebert <ehebert@quantopian.com>
Date: Fri, 20 Feb 2015 16:22:06 -0500
Subject: [PATCH] BUG: Fix div by 0 error due to changed return type.

When calculate_positions_value used np.dot, the return type was a
np.float64. Which allows the use of 0.0 in division to not raise an
exception.

Fix by expliciting creating an np.float64 with 0 value.
---
 zipline/finance/performance/period.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/zipline/finance/performance/period.py b/zipline/finance/performance/period.py
index f027920f..83c0671a 100644
--- a/zipline/finance/performance/period.py
+++ b/zipline/finance/performance/period.py
@@ -351,7 +351,7 @@ class PerformancePeriod(object):
 
     def calculate_positions_value(self):
         if len(self.position_values) == 0:
-            return 0
+            return np.float64(0)
 
         return sum(self.position_values)