diff --git a/dlpdb/coords2dihedrals.py b/dlpdb/coords2dihedrals.py
index 28ed4b3..020682a 100755
--- a/dlpdb/coords2dihedrals.py
+++ b/dlpdb/coords2dihedrals.py
@@ -74,7 +74,7 @@ def cross_prod_v3(a,b):
 
 def main():
 
-    branch_of_log = 2.0*pi  # by default, dihedral angles lie in range: [0, 360.0)
+    branch_of_log = pi  # by default, dihedral angles lie in range: [-180,180.0)
     truncate_a    = 0
     truncate_b    = 0
 
diff --git a/setup.py b/setup.py
index 81004b8..7bb9946 100644
--- a/setup.py
+++ b/setup.py
@@ -16,9 +16,9 @@
 
   url='https://github.com/jewettaij/dlpdb',
 
-  download_url='https://github.com/jewettaij/dlpdb/archive/v0.3.0.zip',
+  download_url='https://github.com/jewettaij/dlpdb/archive/v0.3.1.zip',
 
-  version='0.3.0',
+  version='0.3.1',
 
   license='MIT',