X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?p=ginac.git;a=blobdiff_plain;f=ginac%2Ftensor.cpp;h=d16bbfce4b7949b85359f926767673c5f66c839f;hp=c7a68bf2c1f602c57b311be4899cbdb20e17b083;hb=43e0a8f5ca5e1c48cef5daaf014acdbca4e44568;hpb=50dc516836ac5e91f4f60a60b9a307b375247e7c

diff --git a/ginac/tensor.cpp b/ginac/tensor.cpp
index c7a68bf2..d16bbfce 100644
--- a/ginac/tensor.cpp
+++ b/ginac/tensor.cpp
@@ -29,6 +29,7 @@
 #include "relational.h"
 #include "lst.h"
 #include "numeric.h"
+#include "print.h"
 #include "archive.h"
 #include "utils.h"
 #include "debugmsg.h"
@@ -439,4 +440,16 @@ ex lorentz_eps(const ex & i1, const ex & i2, const ex & i3, const ex & i4, bool
 	return indexed(tensepsilon(true, pos_sig), indexed::antisymmetric, i1, i2, i3, i4);
 }
 
+ex eps0123(const ex & i1, const ex & i2, const ex & i3, const ex & i4, bool pos_sig)
+{
+	if (!is_ex_of_type(i1, varidx) || !is_ex_of_type(i2, varidx) || !is_ex_of_type(i3, varidx) || !is_ex_of_type(i4, varidx))
+		throw(std::invalid_argument("indices of epsilon tensor must be of type varidx"));
+
+	ex dim = ex_to_idx(i1).get_dim();
+	if (dim.is_equal(4))
+		return lorentz_eps(i1, i2, i3, i4, pos_sig);
+	else
+		return indexed(tensepsilon(true, pos_sig), indexed::antisymmetric, i1, i2, i3, i4);
+}
+
 } // namespace GiNaC