Explicit function disambiguation.

[ginac.git] / ginac / symmetry.cpp

diff --git a/ginac/symmetry.cpp b/ginac/symmetry.cpp
index 9e00a8c843633fdfece0c0ab9715343a9ddd7e02..23f9df903b98bd1d12a4f60532e6809b69d5ac23 100644 (file)
--- a/ginac/symmetry.cpp
+++ b/ginac/symmetry.cpp
@@ -3,7 +3,7 @@
  *  Implementation of GiNaC's symmetry definitions. */
 
 /*
- *  GiNaC Copyright (C) 1999-2009 Johannes Gutenberg University Mainz, Germany
+ *  GiNaC Copyright (C) 1999-2010 Johannes Gutenberg University Mainz, Germany
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -190,7 +190,8 @@ unsigned symmetry::calchash() const
 
        if (type == none) {
                v = rotate_left(v);
-               v ^= *(indices.begin());
+               if (!indices.empty())
+                       v ^= *(indices.begin());
        } else {
                for (exvector::const_iterator i=children.begin(); i!=children.end(); ++i)
                {