diff --git a/simanneal/anneal.py b/simanneal/anneal.py
index <HASH>..<HASH> 100644
--- a/simanneal/anneal.py
+++ b/simanneal/anneal.py
@@ -50,7 +50,7 @@ class Annealer(object):
     start = None
 
     def __init__(self, initial_state=None, load_state=None):
-        if initial_state:
+        if initial_state is not None:
             self.state = self.copy_state(initial_state)
         elif load_state:
             self.state = self.load_state(load_state)
Support any type of state variable

icluding numpy.array and pandas.DataFrame