epsilon tensor contractions didn't work with variance-less indices

[ginac.git] / ginac / tensor.cpp

diff --git a/ginac/tensor.cpp b/ginac/tensor.cpp
index b7ae299838b3bb73003ac38e382ff615a31d5804..af085ece2ccb1bdef1c1361d7f058839c83f1d4c 100644 (file)
--- a/ginac/tensor.cpp
+++ b/ginac/tensor.cpp
@@ -493,13 +493,16 @@ bool tensepsilon::contract_with(exvector::iterator self, exvector::iterator othe
 
                // Contraction of two epsilon tensors is a determinant
                ex dim = ex_to<idx>(self->op(1)).get_dim();
+               bool variance = is_a<varidx>(self->op(1));
                matrix M(num, num);
                for (int i=0; i<num; i++) {
                        for (int j=0; j<num; j++) {
                                if (minkowski)
                                        M(i, j) = lorentz_g(self->op(i+1), other->op(j+1), pos_sig);
-                               else
+                               else if (variance)
                                        M(i, j) = metric_tensor(self->op(i+1), other->op(j+1));
+                               else
+                                       M(i, j) = delta_tensor(self->op(i+1), other->op(j+1));
                        }
                }
                int sign = minkowski ? -1 : 1;