/** This returns the linear combination d.a.b.c+I*f.a.b.c. */
ex color_h(const ex & a, const ex & b, const ex & c);
+/** Calculate the trace of an expression containing color objects with a
+ * specified representation label.
+ *
+ * @param rl Representation label */
+ex color_trace(const ex & e, unsigned char rl = 0);
+
} // namespace GiNaC