clifford and color objects are not contracted if their representation labels

[ginac.git] / ginac / color.cpp

diff --git a/ginac/color.cpp b/ginac/color.cpp
index aeaf112c6e16adb9e9b9906a74bb9c3bca86eab6..7d71facf896eb9aca5b0f32126ec4dc0a7480678 100644 (file)
--- a/ginac/color.cpp
+++ b/ginac/color.cpp
@@ -308,6 +308,11 @@ bool su3t::contract_with(exvector::iterator self, exvector::iterator other, exve
 
        if (is_ex_exactly_of_type(other->op(0), su3t)) {
 
+               // Contraction only makes sense if the represenation labels are equal
+               GINAC_ASSERT(is_a<color>(*other));
+               if (ex_to<color>(*other).get_representation_label() != rl)
+                       return false;
+
                // T.a T.a = 4/3 ONE
                if (other - self == 1) {
                        *self = numeric(4, 3);