Tensor.h

Go to the documentation of this file.

/*
   For more information, please see: http://software.sci.utah.edu

   The MIT License

   Copyright (c) 2009 Scientific Computing and Imaging Institute,
   University of Utah.

   
   Permission is hereby granted, free of charge, to any person obtaining a
   copy of this software and associated documentation files (the "Software"),
   to deal in the Software without restriction, including without limitation
   the rights to use, copy, modify, merge, publish, distribute, sublicense,
   and/or sell copies of the Software, and to permit persons to whom the
   Software is furnished to do so, subject to the following conditions:

   The above copyright notice and this permission notice shall be included
   in all copies or substantial portions of the Software.

   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
   OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
   THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
   DEALINGS IN THE SOFTWARE.
*/


///
///@file  Tensor.h
///@brief Symmetric, positive definite tensors (diffusion, conductivity)
///
///@author
///       David Weinstein
///       Department of Computer Science
///       University of Utah
///@date  March 2001
///

#ifndef Geometry_Tensor_h
#define Geometry_Tensor_h 1

#include <Core/Utils/Legacy/TypeDescription.h>
#include <Core/Utils/Legacy/Assert.h>
#include <Core/Containers/Array1.h>
#include <Core/GeometryPrimitives/Vector.h>
#include <Core/GeometryPrimitives/share.h>

#include <string>
#include <iosfwd>
#include <vector>


namespace SCIRun {

  class Piostream;
  class RigorousTest;
  class TypeDescription;

  namespace Core {

    namespace Geometry {

class SCISHARE Tensor {

public:
  Tensor();
  Tensor(const Tensor&);
  explicit Tensor(int);
  explicit Tensor(double);
  Tensor(double, double, double, double, double, double);  
  explicit Tensor(const Array1<double> &); // 6 values
  explicit Tensor(const std::vector<double> &); // 6 values
  explicit Tensor(const double *); // 6 values
  explicit Tensor(const double **);
  Tensor(const Vector&, const Vector&, const Vector&);
  Tensor& operator=(const Tensor&);
  Tensor& operator=(const double&);
  
  bool operator==(const Tensor&) const;
  bool operator!=(const Tensor&) const;

  Tensor operator+(const Tensor&) const;
  Tensor& operator+=(const Tensor&);
  Tensor operator-(const Tensor&) const;
  Tensor& operator-=(const Tensor&);
  Tensor operator*(const double) const;
  Vector operator*(const Vector) const;

  static std::string type_name(int i = -1);
  
  double mat_[3][3];

  void build_mat_from_eigens();
  void build_eigens_from_mat(); 
  void get_eigenvectors(Vector &e1, Vector &e2, Vector &e3);
  const Vector &get_eigenvector1() { ASSERT(have_eigens_); return e1_; }
  const Vector &get_eigenvector2() { ASSERT(have_eigens_); return e2_; }
  const Vector &get_eigenvector3() { ASSERT(have_eigens_); return e3_; }
  void get_eigenvalues(double &l1, double &l2, double &l3);

  double norm();

  bool have_eigens() { return have_eigens_; }
 
  void set_eigens(const Vector &e1, const Vector &e2, const Vector &e3);

  // This directly sets the eigenvectors and values in the tensor.  It
  // is meant to be used in conjunction with custom eigenvector/value
  // computation, such as that found in the TEEM package.
  void set_outside_eigens(const Vector &e1, const Vector &e2,
              const Vector &e3,
              double v1, double v2, double v3);

  /// support dynamic compilation
  static const std::string& get_h_file_path();

  friend SCISHARE void Pio(Piostream&, Tensor&);

  inline double xx() const { return mat_[0][0]; }
  inline double xy() const { return mat_[1][0]; }
  inline double xz() const { return mat_[2][0]; }
  inline double yy() const { return mat_[1][1]; }
  inline double yz() const { return mat_[2][1]; }
  inline double zz() const { return mat_[2][2]; }

private:
  Vector e1_, e2_, e3_;  // these are already scaled by the eigenvalues
  double l1_, l2_, l3_;
  bool have_eigens_;
};

SCISHARE void Pio(Piostream&, Tensor&);

inline bool operator<(Tensor t1, Tensor t2)
{
  return(t1.norm()<t2.norm());
}

inline bool operator<=(Tensor t1, Tensor t2)
{
  return(t1.norm()<=t2.norm());
}

inline bool operator>(Tensor t1, Tensor t2)
{
  return(t1.norm()>t2.norm());
}

inline bool operator>=(Tensor t1, Tensor t2)
{
  return(t1.norm()>=t2.norm());
}

inline 
Tensor operator*(double d, const Tensor &t) {
  return t*d;
}

SCISHARE std::ostream& operator<<(std::ostream& os, const Tensor& t);
SCISHARE std::istream& operator>>(std::istream& os, Tensor& t);

SCISHARE const TypeDescription* get_type_description(Tensor*);
    }}

  

} // End namespace SCIRun

#endif // Geometry_Tensor_h