Transform.h

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#ifndef AMPGEN_TRANSFORM_H
#define AMPGEN_TRANSFORM_H
 
#include "AmpGen/Expression.h"
#include "AmpGen/Tensor.h"
#include "AmpGen/DiracMatrices.h"
 
namespace AmpGen {
  Expression cosh(const Expression &x);
  Expression sinh(const Expression &x);
  Expression tanh(const Expression &x);
 
  Expression acosh(const Expression &x);
  Expression asinh(const Expression &x);
  Expression atanh(const Expression &x);
 
  class Transform {
  public:
    enum Type { Boost, Rotate };
    enum Representation { Spinor, Bispinor, Vector };
 
    Transform(const Expression &arg, const Tensor &k, const Type &type);
    Transform inverse() const;
    Tensor operator()(const Representation &repr) const;
    Tensor operator()(const Tensor &tensor, const Representation &repr = Representation::Vector) const;
 
  private:
    Tensor sigma_dot_p(const Tensor &p) const;
    Tensor J_dot_p(const Tensor &p) const;
    Tensor K_dot_p(const Tensor &p) const;
    Tensor make_bispinor_operator(const Tensor &A, const Tensor &B, const Tensor &C, const Tensor &D) const;
    Tensor rotate_spinor() const;
    Tensor boost_spinor() const;
 
    Expression m_arg;
    Tensor m_k;
    Type m_type;
  };
 
  class TransformSequence {
  public:
    TransformSequence();
    TransformSequence(const Transform &transform);
    TransformSequence(const TransformSequence &t1, const TransformSequence &t2);
    TransformSequence(const Transform &t1, const Transform &t2);
    TransformSequence inverse() const;
    Tensor operator()(const Transform::Representation &repr) const;
    Tensor operator()(const Tensor &tensor, const Transform::Representation &repr = Transform::Representation::Vector) const;
    void push_back(const Transform &transform);
    void push_back(const TransformSequence &transform);
    void stepThrough(const Tensor &tensor, const Transform::Representation &repr = Transform::Representation::Vector);
 
    void clear();
    std::vector<Transform>::reverse_iterator rbegin() { return m_transforms.rbegin(); }
    std::vector<Transform>::reverse_iterator rend() { return m_transforms.rend(); }
    std::vector<Transform>::const_iterator begin() const { return m_transforms.cbegin(); }
    std::vector<Transform>::const_iterator end() const { return m_transforms.cend(); }
    std::vector<Transform>::iterator begin() { return m_transforms.begin(); }
    std::vector<Transform>::iterator end() { return m_transforms.end(); }
    unsigned size() const { return m_transforms.size(); }
 
  private:
    void buildCache();
    std::vector<Transform> m_transforms;
    std::array<Tensor, 3> m_cache;
  };
 
}
 
#endif