/** This class holds a generator T_a or the unity element of the Lie algebra
* of SU(3), as used for calculations in quantum chromodynamics. A
- * representation label (an unsigned integer) is used to distinguish
- * elements from different Lie algebra representations (only objects with
- * the same label "interact" with each other). These objects implement an
- * abstract representation of the group, not a specific matrix
- * representation. The indices used for color objects should not have a
- * variance. */
+ * representation label (an unsigned 8-bit integer) is used to distinguish
+ * elements from different Lie algebras (objects with different labels
+ * commute). These objects implement an abstract representation of the
+ * group, not a specific matrix representation. The indices used for color
+ * objects should not have a variance. */
class color : public indexed
{
GINAC_DECLARE_REGISTERED_CLASS(color, indexed)
// other constructors
public:
- color(const ex & b, unsigned rl = 0);
- color(const ex & b, const ex & i1, unsigned rl = 0);
+ color(const ex & b, unsigned char rl = 0);
+ color(const ex & b, const ex & i1, unsigned char rl = 0);
// internal constructors
- color(unsigned rl, const exvector & v, bool discardable = false);
- color(unsigned rl, exvector * vp); // vp will be deleted
+ color(unsigned char rl, const exvector & v, bool discardable = false);
+ color(unsigned char rl, exvector * vp); // vp will be deleted
// functions overriding virtual functions from base classes
protected:
ex thisexprseq(const exvector & v) const;
ex thisexprseq(exvector * vp) const;
unsigned return_type(void) const { return return_types::noncommutative; }
- unsigned return_type_tinfo(void) const { return TINFO_color; }
+ unsigned return_type_tinfo(void) const { return TINFO_color + representation_label; }
// member variables
private:
- unsigned representation_label; /**< Representation label to distinguish independent color matrices coming from separated fermion lines */
+ unsigned char representation_label; /**< Representation label to distinguish independent color matrices coming from separated fermion lines */
};
*
* @param rl Representation label
* @return newly constructed unity element */
-ex color_ONE(unsigned rl = 0);
+ex color_ONE(unsigned char rl = 0);
/** Create an su(3) generator.
*
* @param a Index
* @param rl Representation label
* @return newly constructed unity generator */
-ex color_T(const ex & a, unsigned rl = 0);
+ex color_T(const ex & a, unsigned char rl = 0);
/** Create an su(3) antisymmetric structure constant.
*