CubicEquation Class Reference

A class for a cubic equation. Used for eigenvalue calculation on 3D matrices. More...

#include <cube_eq.h>

Public Member Functions
	CubicEquation (double, double, double)
set< double >	getRealRoots (double)

Private Member Functions
double	bisect (double, double, double)
double	f (double)

Private Attributes
double	m_a
double	m_b
double	m_c

Detailed Description

A class for a cubic equation. Used for eigenvalue calculation on 3D matrices.

Author

Steffen Abe $Revision$ $Date$

Constructor & Destructor Documentation

CubicEquation()

CubicEquation::CubicEquation	(	double	a,
		double	b,
		double	c
	)

construct cubic equation of the form x^3+ax^2+bx+c

Parameters

a	coefficient for x^2
b	coefficient for x
c	constant coefficient

References m_a, m_b, and m_c.

Member Function Documentation

bisect()

double CubicEquation::bisect ( double  x_0, double  x_1, double  tol  )

private

References f().

Referenced by getRealRoots().

Here is the call graph for this function:

Here is the caller graph for this function:

f()

double CubicEquation::f ( double  x )

private

return x^3+ax^2+bx+c

Parameters

x

References m_a, m_b, and m_c.

Referenced by bisect(), and getRealRoots().

Here is the caller graph for this function:

getRealRoots()

set< double > CubicEquation::getRealRoots

(

double

tol

)

Get the roots. Get one root (r_1) by a bisection method and the other 2 (if real) by solving the quadratic equation resulting from dividing the eqation by (x-r_1). Returns the roots as a STL-set so they are ordered.

Parameters

tol	the precision of the calculation
valid	returns the validity of the result, i.e. if valid==false there was no positive root found

References bisect(), f(), m_a, m_b, and m_c.

Referenced by Matrix3::eigen().

Here is the call graph for this function:

Here is the caller graph for this function:

Member Data Documentation

m_a

double CubicEquation::m_a

private

Referenced by CubicEquation(), f(), and getRealRoots().

m_b

double CubicEquation::m_b

private

Referenced by CubicEquation(), f(), and getRealRoots().

m_c

double CubicEquation::m_c

private

Referenced by CubicEquation(), f(), and getRealRoots().

---

The documentation for this class was generated from the following files:

• Foundation/cube_eq.h
• Foundation/cube_eq.cpp