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137 lines
3.8 KiB
C++

#ifndef GFXSYMMAT3_INCLUDED // -*- C++ -*-
#define GFXSYMMAT3_INCLUDED
#if !defined(__GNUC__)
# pragma once
#endif
/************************************************************************
Symmetric 3x3 Matrix class
$Id: symmat3.h 427 2004-09-27 04:45:31Z garland $
************************************************************************/
#include "mat3.h"
namespace gfx
{
class SymMat3
{
private:
double elt[6];
inline int index(int i, int j) const
{
// if n=dim(), and if i<=j:
// index = ( n*(n+1)/2 - (n-i)*(n-i+1)/2 ) + (j-i)
//
if( i<=j ) return 6 - (3-i)*(4-i)/2 + (j-i);
else return 6 - (3-j)*(4-j)/2 + (i-j);
}
public:
// Standard constructors
//
SymMat3(double s=0.0) { *this = s; }
SymMat3(const SymMat3& m) { *this = m; }
double& operator()(int i, int j) { return elt[index(i,j)]; }
double operator()(int i, int j) const { return elt[index(i,j)]; }
static int size() { return 6; }
static int dim() { return 3; }
typedef Vec3 vector_type;
typedef Mat3 inverse_type;
typedef double value_type;
operator double*() { return elt; }
operator const double*() { return elt; }
operator const double*() const { return elt; }
inline Vec3 row(int i) const;
inline Vec3 col(int j) const;
Mat3 fullmatrix() const;
inline SymMat3& operator=(const SymMat3& m);
inline SymMat3& operator=(double s);
inline SymMat3& operator+=(const SymMat3& m);
inline SymMat3& operator-=(const SymMat3& m);
inline SymMat3& operator*=(double s);
inline SymMat3& operator/=(double s);
static SymMat3 I();
static SymMat3 outer_product(const Vec3& v);
};
////////////////////////////////////////////////////////////////////////
//
// Methods definitions
//
inline Vec3 SymMat3::row(int i) const
{ return Vec3((*this)(i, 0), (*this)(i, 1), (*this)(i, 2)); }
inline Vec3 SymMat3::col(int j) const
{ return Vec3((*this)(0, j), (*this)(1, j), (*this)(2, j)); }
inline SymMat3& SymMat3::operator=(const SymMat3& m)
{ for(int i=0; i<size(); i++) elt[i]=m.elt[i]; return *this; }
inline SymMat3& SymMat3::operator=(double s)
{ for(int i=0; i<size(); i++) elt[i]=s; return *this; }
inline SymMat3& SymMat3::operator+=(const SymMat3& m)
{ for(int i=0; i<size(); i++) elt[i]+=m.elt[i]; return *this; }
inline SymMat3& SymMat3::operator-=(const SymMat3& m)
{ for(int i=0; i<size(); i++) elt[i]-=m.elt[i]; return *this; }
inline SymMat3& SymMat3::operator*=(double s)
{ for(int i=0; i<size(); i++) elt[i]*=s; return *this; }
inline SymMat3& SymMat3::operator/=(double s)
{ for(int i=0; i<size(); i++) elt[i]/=s; return *this; }
////////////////////////////////////////////////////////////////////////
//
// Operator definitions
//
inline SymMat3 operator+(SymMat3 n, const SymMat3& m) { n += m; return n; }
inline SymMat3 operator-(SymMat3 n, const SymMat3& m) { n -= m; return n; }
inline SymMat3 operator*(double s, SymMat3 m) { m*=s; return m; }
inline SymMat3 operator*(SymMat3 m, double s) { m*=s; return m; }
inline SymMat3 operator/(SymMat3 m, double s) { m/=s; return m; }
inline Vec3 operator*(const SymMat3& m, const Vec3& v)
{ return Vec3(m.row(0)*v, m.row(1)*v, m.row(2)*v); }
extern SymMat3 operator*(const SymMat3& n, const SymMat3& m);
extern std::ostream &operator<<(std::ostream &out, const SymMat3& M);
////////////////////////////////////////////////////////////////////////
//
// Misc. function definitions
//
inline double det(const SymMat3& m) { return m.row(0) * (m.row(1)^m.row(2)); }
inline double trace(const SymMat3& m) { return m(0,0) + m(1,1) + m(2,2); }
inline SymMat3 transpose(const SymMat3& m) { return m; }
extern double invert(Mat3& m_inv, const SymMat3& m);
extern bool eigen(const SymMat3& m, Vec3& eig_vals, Vec3 eig_vecs[3]);
} // namespace gfx
// GFXSYMMAT3_INCLUDED
#endif