- dirac_trace() handles arbitrary expressions (even unexpanded), including

[ginac.git] / ginac / tensor.h

diff --git a/ginac/tensor.h b/ginac/tensor.h
index 9c4d2c36137a8a6dd7b049bf3d055b639b7f4398..b077ee4d0c927d8e459250bb0092773b8c876163 100644 (file)
--- a/ginac/tensor.h
+++ b/ginac/tensor.h
@@ -53,7 +53,7 @@ class tensdelta : 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;
        ex eval_indexed(const basic & i) const;
        bool contract_with(exvector::iterator self, exvector::iterator other, exvector & v) const;
 };
@@ -68,7 +68,7 @@ class tensmetric : 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;
        ex eval_indexed(const basic & i) const;
        bool contract_with(exvector::iterator self, exvector::iterator other, exvector & v) const;
 };
@@ -88,7 +88,7 @@ public:
 
        // 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;
        ex eval_indexed(const basic & i) const;
 
        // member variables
@@ -104,9 +104,19 @@ class tensepsilon : public tensor
 {
        GINAC_DECLARE_REGISTERED_CLASS(tensepsilon, tensor)
 
+       // other constructors
+public:
+       tensepsilon(bool minkowski, bool pos_sig);
+
        // 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;
+       ex eval_indexed(const basic & i) const;
+
+       // member variables
+private:
+       bool minkowski; /**< If true, tensor is in Minkowski-type space. Otherwise it is in a Euclidean space. */
+       bool pos_sig;  /**< If true, the metric is assumed to be diag(-1,1,1...). Otherwise it is diag(1,-1,-1,...). This is only relevant if minkowski = true. */
 };
 
 
@@ -125,9 +135,9 @@ inline const tensor &ex_to_tensor(const ex &e)
  *  @return newly constructed delta tensor */
 ex delta_tensor(const ex & i1, const ex & i2);
 
-/** Create a metric tensor with specified indices. The indices must be of
- *  class varidx or a subclass. A metric tensor with one covariant and one
- *  contravariant index is equivalent to the delta tensor.
+/** Create a symmetric metric tensor with specified indices. The indices
+ *  must be of class varidx or a subclass. A metric tensor with one
+ *  covariant and one contravariant index is equivalent to the delta tensor.
  *
  *  @param i1 First index
  *  @param i2 Second index
@@ -145,14 +155,46 @@ ex metric_tensor(const ex & i1, const ex & i2);
  *  @return newly constructed Lorentz metric tensor */
 ex lorentz_g(const ex & i1, const ex & i2, bool pos_sig = false);
 
-/** Create an epsilon tensor with two indices. The indices must be of class
- *  idx or a subclass, and have a dimension of 2.
+/** Create an epsilon tensor in a Euclidean space with two indices. The
+ *  indices must be of class idx or a subclass, and have a dimension of 2.
  *
  *  @param i1 First index
  *  @param i2 Second index
  *  @return newly constructed epsilon tensor */
 ex epsilon_tensor(const ex & i1, const ex & i2);
 
+/** Create an epsilon tensor in a Euclidean space with three indices. The
+ *  indices must be of class idx or a subclass, and have a dimension of 3.
+ *
+ *  @param i1 First index
+ *  @param i2 Second index
+ *  @param i3 Third index
+ *  @return newly constructed epsilon tensor */
+ex epsilon_tensor(const ex & i1, const ex & i2, const ex & i3);
+
+/** Create an epsilon tensor in a Minkowski space with four indices. The
+ *  indices must be of class varidx or a subclass, and have a dimension of 4.
+ *
+ *  @param i1 First index
+ *  @param i2 Second index
+ *  @param i3 Third index
+ *  @param i4 Fourth index
+ *  @param pos_sig Whether the signature of the metric is positive
+ *  @return newly constructed epsilon tensor */
+ex lorentz_eps(const ex & i1, const ex & i2, const ex & i3, const ex & i4, bool pos_sig = false);
+
+/** Create an epsilon tensor in a 4-dimensional projection of a D-dimensional
+ *  Minkowski space. It vanishes whenever one of the indices is not in the
+ *  set {0, 1, 2, 3}.
+ *
+ *  @param i1 First index
+ *  @param i2 Second index
+ *  @param i3 Third index
+ *  @param i4 Fourth index
+ *  @param pos_sig Whether the signature of the metric is positive
+ *  @return newly constructed epsilon tensor */
+ex eps0123(const ex & i1, const ex & i2, const ex & i3, const ex & i4, bool pos_sig = false);
+
 } // namespace GiNaC
 
 #endif // ndef __GINAC_TENSOR_H__