- added Clifford algebra unity element

[ginac.git] / ginac / clifford.h

diff --git a/ginac/clifford.h b/ginac/clifford.h
index 49a3613b13f9424f68f143d98735655b89a88592..0feef3f049b135c3984af3bfba8f52df5df70923 100644 (file)
--- a/ginac/clifford.h
+++ b/ginac/clifford.h
@@ -1,9 +1,9 @@
 /** @file clifford.h
  *
- *  Interface to GiNaC's clifford objects. */
+ *  Interface to GiNaC's clifford algebra (Dirac gamma) objects. */
 
 /*
- *  GiNaC Copyright (C) 1999 Johannes Gutenberg University Mainz, Germany
+ *  GiNaC Copyright (C) 1999-2001 Johannes Gutenberg University Mainz, Germany
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -23,73 +23,80 @@
 #ifndef __GINAC_CLIFFORD_H__
 #define __GINAC_CLIFFORD_H__
 
-#include <string>
-#include <ginac/indexed.h>
-#include <ginac/ex.h>
+#include "indexed.h"
+#include "tensor.h"
 
 namespace GiNaC {
 
-/** Base class for clifford object */
+
+/** 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. */
 class clifford : public indexed
 {
-// member functions
+       GINAC_DECLARE_REGISTERED_CLASS(clifford, indexed)
 
-    // default constructor, destructor, copy constructor assignment operator and helpers
+       // other constructors
 public:
-    clifford();
-    ~clifford();
-    clifford(clifford const & other);
-    clifford const & operator=(clifford const & other);
-protected:
-    void copy(clifford const & other); 
-    void destroy(bool call_parent);
+       clifford(const ex & b);
+       clifford(const ex & b, const ex & mu);
 
-    // other constructors
-public:
-    explicit clifford(string const & initname);
+       // internal constructors
+       clifford(const exvector & v, bool discardable = false);
+       clifford(exvector * vp); // vp will be deleted
 
-    // functions overriding virtual functions from base classes
-public:
-    basic * duplicate() const;
-    void printraw(ostream & os) const;
-    void printtree(ostream & os, unsigned indent) const;
-    void print(ostream & os, unsigned upper_precedence=0) const;
-    void printcsrc(ostream & os, unsigned type, unsigned upper_precedence=0) const;
-    bool info(unsigned inf) const;
+       // functions overriding virtual functions from base classes
 protected:
-    int compare_same_type(basic const & other) const;
-    ex simplify_ncmul(exvector const & v) const;
-    unsigned calchash(void) const;
-
-    // new virtual functions which can be overridden by derived classes
-    // none
-    
-    // non-virtual functions in this class
-public:
-    void setname(string const & n);
-private:
-    string & autoname_prefix(void);
+       ex simplify_ncmul(const exvector & v) const;
+       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; }
+};
 
-// member variables
 
-protected:
-    string name;
-    unsigned serial; // unique serial number for comparision
-private:
-    static unsigned next_serial;
+/** 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(std::ostream & os, unsigned upper_precedence=0) const;
 };
 
-// global constants
 
-extern const clifford some_clifford;
-extern type_info const & typeid_clifford;
+/** This class represents the Dirac gamma Lorentz vector. */
+class diracgamma : public tensor
+{
+       GINAC_DECLARE_REGISTERED_CLASS(diracgamma, tensor)
 
-// utility functions
+       // functions overriding virtual functions from bases classes
+public:
+       void print(std::ostream & os, unsigned upper_precedence=0) const;
+       bool contract_with(exvector::iterator self, exvector::iterator other, exvector & v) const;
+};
+
+
+// global functions
 inline const clifford &ex_to_clifford(const ex &e)
 {
        return static_cast<const clifford &>(*e.bp);
 }
 
+
+/** Create a Clifford unity object.
+ *
+ *  @return newly constructed object */
+ex dirac_one(void);
+
+/** Create a Dirac gamma object.
+ *
+ *  @param mu Index (must be of class varidx or a derived class)
+ *  @return newly constructed gamma object */
+ex dirac_gamma(const ex & mu);
+
+
 } // namespace GiNaC
 
 #endif // ndef __GINAC_CLIFFORD_H__