X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?p=ginac.git;a=blobdiff_plain;f=ginac%2Ftensor.h;h=147ab44d9bf7f414d766c598d0f81ba95c5fed83;hp=ac991d5f666f5e47d621e1829bdf5f3bd4b2c048;hb=05c47b615d0d309d4868c688cd26f68376fa4277;hpb=aef64ef1f63f7b4cb9236c5c189873e48c6c999b

diff --git a/ginac/tensor.h b/ginac/tensor.h
index ac991d5f..147ab44d 100644
--- a/ginac/tensor.h
+++ b/ginac/tensor.h
@@ -40,8 +40,6 @@ protected:
 	tensor(unsigned ti);
 
 	// functions overriding virtual functions from bases classes
-public:
-	ex subs(const lst & ls, const lst & lr) const;
 protected:
 	unsigned return_type(void) const { return return_types::noncommutative_composite; }
 };
@@ -55,7 +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;
 };
@@ -70,7 +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;
 };
@@ -90,7 +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
@@ -99,6 +97,22 @@ private:
 };
 
 
+/** This class represents an antisymmetric spinor metric tensor which
+ *  can be used to raise/lower indices of 2-component Weyl spinors. If
+ *  indexed, it must have exactly two indices of the same type which
+ *  must be of class spinidx or a subclass and have dimension 2. */
+class spinmetric : public tensmetric
+{
+	GINAC_DECLARE_REGISTERED_CLASS(spinmetric, tensmetric)
+
+	// functions overriding virtual functions from bases classes
+public:
+	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;
+};
+
+
 /** This class represents the totally antisymmetric epsilon tensor. If
  *  indexed, all indices must be of the same type and their number must
  *  be equal to the dimension of the index space. */
@@ -112,7 +126,7 @@ 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
@@ -123,6 +137,9 @@ private:
 
 
 // utility functions
+
+/** Return the tensor object handled by an ex.  Deprecated: use ex_to<tensor>().
+ *  This is unsafe: you need to check the type first. */
 inline const tensor &ex_to_tensor(const ex &e)
 {
 	return static_cast<const tensor &>(*e.bp);
@@ -157,6 +174,16 @@ 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 a spinor metric tensor with specified indices. The indices must be
+ *  of class spinidx or a subclass and have a dimension of 2. The spinor
+ *  metric is an antisymmetric tensor with a matrix representation of
+ *  [[ [[ 0, 1 ]], [[ -1, 0 ]] ]].
+ *
+ *  @param i1 First index
+ *  @param i2 Second index
+ *  @return newly constructed spinor metric tensor */
+ex spinor_metric(const ex & i1, const ex & i2);
+
 /** 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.
  *
@@ -185,6 +212,18 @@ ex epsilon_tensor(const ex & i1, const ex & i2, const ex & i3);
  *  @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__