X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?p=ginac.git;a=blobdiff_plain;f=ginac%2Fclifford.h;h=f1783396995620d63c1a38f24315675f97476742;hp=ccb16bf24c78fa2733a4d759c831a6b1de6af2bc;hb=53604c3e255c392fb31af8bcecf57f2918495d28;hpb=7a2377582665c467fc65d6e3a4f60def5f7535ae

diff --git a/ginac/clifford.h b/ginac/clifford.h
index ccb16bf2..f1783396 100644
--- a/ginac/clifford.h
+++ b/ginac/clifford.h
@@ -31,18 +31,21 @@ namespace GiNaC {
 
 /** This class holds an object representing an element of the Clifford
  *  algebra (the Dirac gamma matrices). These objects only carry Lorentz
- *  indices. Spinor indices are hidden. */
+ *  indices. Spinor indices are hidden. A representation label (an unsigned
+ *  8-bit integer) is used to distinguish elements from different Clifford
+ *  algebras (objects with different labels commute). */
 class clifford : public indexed
 {
 	GINAC_DECLARE_REGISTERED_CLASS(clifford, indexed)
 
 	// other constructors
 public:
-	clifford(const ex & b, const ex & mu);
+	clifford(const ex & b, unsigned char rl = 0);
+	clifford(const ex & b, const ex & mu, unsigned char rl = 0);
 
 	// internal constructors
-	clifford(const exvector & v, bool discardable = false);
-	clifford(exvector * vp); // vp will be deleted
+	clifford(unsigned char rl, const exvector & v, bool discardable = false);
+	clifford(unsigned char rl, exvector * vp); // vp will be deleted
 
 	// functions overriding virtual functions from base classes
 protected:
@@ -50,7 +53,26 @@ 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_clifford; }
+	unsigned return_type_tinfo(void) const { return TINFO_clifford + representation_label; }
+
+	// non-virtual functions in this class
+public:
+	unsigned char get_representation_label(void) const {return representation_label;}
+
+	// member variables
+private:
+	unsigned char representation_label; /**< Representation label to distinguish independent spin lines */
+};
+
+
+/** This class represents the Clifford algebra unity element. */
+class diracone : public tensor
+{
+	GINAC_DECLARE_REGISTERED_CLASS(diracone, tensor)
+
+	// functions overriding virtual functions from bases classes
+public:
+	void print(const print_context & c, unsigned level = 0) const;
 };
 
 
@@ -61,7 +83,19 @@ class diracgamma : public tensor
 
 	// functions overriding virtual functions from bases classes
 public:
-	void print(std::ostream & os, unsigned upper_precedence=0) const;
+	void print(const print_context & c, unsigned level = 0) const;
+	bool contract_with(exvector::iterator self, exvector::iterator other, exvector & v) const;
+};
+
+
+/** This class represents the Dirac gamma5 object. */
+class diracgamma5 : public tensor
+{
+	GINAC_DECLARE_REGISTERED_CLASS(diracgamma5, tensor)
+
+	// functions overriding virtual functions from bases classes
+public:
+	void print(const print_context & c, unsigned level = 0) const;
 };
 
 
@@ -72,11 +106,33 @@ inline const clifford &ex_to_clifford(const ex &e)
 }
 
 
+/** Create a Clifford unity object.
+ *
+ *  @param rl Representation label
+ *  @return newly constructed object */
+ex dirac_ONE(unsigned char rl = 0);
+
 /** Create a Dirac gamma object.
  *
  *  @param mu Index (must be of class varidx or a derived class)
+ *  @param rl Representation label
  *  @return newly constructed gamma object */
-ex dirac_gamma(const ex & mu);
+ex dirac_gamma(const ex & mu, unsigned char rl = 0);
+
+/** Create a Dirac gamma5 object.
+ *
+ *  @param rl Representation label
+ *  @return newly constructed object */
+ex dirac_gamma5(unsigned char rl = 0);
+
+/** Calculate the trace of an expression containing gamma objects with
+ *  a specified representation label. The computed trace is a linear
+ *  functional that is equal to the usual trace only in D = 4 dimensions.
+ *  In particular, the functional is non-cyclic in D != 4 dimensions when
+ *  gamma5 is involved.
+ *
+ *  @param rl Representation label */
+ex dirac_trace(const ex & e, unsigned char rl = 0);
 
 
 } // namespace GiNaC