canonicalize() failed to return zero for an antisymmetric combination of two

or more equal elements if the elements were already in their canonical order

diff --git a/ginac/symmetry.cpp b/ginac/symmetry.cpp
index 8a766214aaa1024d93eaa1992039622a76115887..c953953a2e55eebf2ee081a84ab6904658cb7adb 100644 (file)
--- a/ginac/symmetry.cpp
+++ b/ginac/symmetry.cpp
@@ -304,7 +304,7 @@ public:
 
 int canonicalize(exvector::iterator v, const symmetry &symm)
 {
 
 int canonicalize(exvector::iterator v, const symmetry &symm)
 {

-       // Less than two indices? Then do nothing
+       // Less than two elements? Then do nothing

        if (symm.indices.size() < 2)
                return INT_MAX;
 
        if (symm.indices.size() < 2)
                return INT_MAX;
 


@@ -334,6 +334,8 @@ int canonicalize(exvector::iterator v, const symmetry &symm)
                case symmetry::antisymmetric:
                        // Sort the children in ascending order, keeping track of the signum
                        sign *= permutation_sign(first, last, sy_is_less(v), sy_swap(v, something_changed));
                case symmetry::antisymmetric:
                        // Sort the children in ascending order, keeping track of the signum
                        sign *= permutation_sign(first, last, sy_is_less(v), sy_swap(v, something_changed));

+                       if (sign == 0)
+                               return 0;

                        break;
                case symmetry::cyclic:
                        // Permute the smallest child to the front
                        break;
                case symmetry::cyclic:
                        // Permute the smallest child to the front