Public Member Functions | Static Public Member Functions | Public Attributes | List of all members
QwtSplinePolynomial Class Reference

A cubic polynomial without constant term. More...

#include <qwt_spline_polynomial.h>

Public Member Functions

double curvatureAt (double x) const
 
bool operator!= (const QwtSplinePolynomial &) const
 
bool operator== (const QwtSplinePolynomial &) const
 
 QwtSplinePolynomial (double c3=0.0, double c2=0.0, double c1=0.0)
 Constructor. More...
 
double slopeAt (double x) const
 
double valueAt (double x) const
 

Static Public Member Functions

static QwtSplinePolynomial fromCurvatures (const QPointF &p1, double cv1, const QPointF &p2, double cv2)
 
static QwtSplinePolynomial fromCurvatures (double dx, double dy, double cv1, double cv2)
 
static QwtSplinePolynomial fromSlopes (const QPointF &p1, double m1, const QPointF &p2, double m2)
 
static QwtSplinePolynomial fromSlopes (double x, double y, double m1, double m2)
 

Public Attributes

double c1
 coefficient of the linear summand More...
 
double c2
 coefficient of the quadratic summand More...
 
double c3
 coefficient of the cubic summand More...
 

Detailed Description

A cubic polynomial without constant term.

QwtSplinePolynomial is a 3rd degree polynomial of the form: y = c3 * x³ + c2 * x² + c1 * x;

QwtSplinePolynomial is usually used in combination with polygon interpolation, where it is not necessary to store a constant term ( c0 ), as the translation is known from the corresponding polygon points.

See also
QwtSplineC1

Definition at line 33 of file qwt_spline_polynomial.h.

Constructor & Destructor Documentation

QwtSplinePolynomial::QwtSplinePolynomial ( double  a3 = 0.0,
double  a2 = 0.0,
double  a1 = 0.0 
)
inline

Constructor.

Parameters
a3Coefficient of the cubic summand
a2Coefficient of the quadratic summand
a1Coefficient of the linear summand

Definition at line 77 of file qwt_spline_polynomial.h.

Member Function Documentation

double QwtSplinePolynomial::curvatureAt ( double  x) const
inline

Calculate the value of the second derivate of a polynomial for a given x

Parameters
xParameter
Returns
Curvature at x

Definition at line 130 of file qwt_spline_polynomial.h.

QwtSplinePolynomial QwtSplinePolynomial::fromCurvatures ( const QPointF &  p1,
double  cv1,
const QPointF &  p2,
double  cv2 
)
inlinestatic

Find the coefficients for the polynomial including 2 points with specific values for the 2nd derivates at these points.

Parameters
p1First point
cv1Value of the second derivate at p1
p2Second point
cv2Value of the second derivate at p2
Returns
Coefficients of the polynomials
Note
The missing constant term of the polynomial is p1.y()

Definition at line 185 of file qwt_spline_polynomial.h.

QwtSplinePolynomial QwtSplinePolynomial::fromCurvatures ( double  x,
double  y,
double  cv1,
double  cv2 
)
inlinestatic

Find the coefficients for the polynomial from the offset between 2 points and specific values for the 2nd derivates at these points.

Parameters
dxX-offset
dyY-offset
cv1Value of the second derivate at p1
cv2Value of the second derivate at p2
Returns
Coefficients of the polynomials

Definition at line 202 of file qwt_spline_polynomial.h.

QwtSplinePolynomial QwtSplinePolynomial::fromSlopes ( const QPointF &  p1,
double  m1,
const QPointF &  p2,
double  m2 
)
inlinestatic

Find the coefficients for the polynomial including 2 points with specific values for the 1st derivates at these points.

Parameters
p1First point
m1Value of the first derivate at p1
p2Second point
m2Value of the first derivate at p2
Returns
Coefficients of the polynomials
Note
The missing constant term of the polynomial is p1.y()

Definition at line 147 of file qwt_spline_polynomial.h.

QwtSplinePolynomial QwtSplinePolynomial::fromSlopes ( double  dx,
double  dy,
double  m1,
double  m2 
)
inlinestatic

Find the coefficients for the polynomial from the offset between 2 points and specific values for the 1st derivates at these points.

Parameters
dxX-offset
dyY-offset
m1Value of the first derivate at p1
m2Value of the first derivate at p2
Returns
Coefficients of the polynomials

Definition at line 164 of file qwt_spline_polynomial.h.

bool QwtSplinePolynomial::operator!= ( const QwtSplinePolynomial other) const
inline
Parameters
otherOther polynomial
Returns
true, when the polynomials have different coefficients

Definition at line 97 of file qwt_spline_polynomial.h.

bool QwtSplinePolynomial::operator== ( const QwtSplinePolynomial other) const
inline
Parameters
otherOther polynomial
Returns
true, when both polynomials have the same coefficients

Definition at line 88 of file qwt_spline_polynomial.h.

double QwtSplinePolynomial::slopeAt ( double  x) const
inline

Calculate the value of the first derivate of a polynomial for a given x

Parameters
xParameter
Returns
Slope at x

Definition at line 119 of file qwt_spline_polynomial.h.

double QwtSplinePolynomial::valueAt ( double  x) const
inline

Calculate the value of a polynomial for a given x

Parameters
xParameter
Returns
Value at x

Definition at line 108 of file qwt_spline_polynomial.h.

Member Data Documentation

double QwtSplinePolynomial::c1

coefficient of the linear summand

Definition at line 67 of file qwt_spline_polynomial.h.

double QwtSplinePolynomial::c2

coefficient of the quadratic summand

Definition at line 64 of file qwt_spline_polynomial.h.

double QwtSplinePolynomial::c3

coefficient of the cubic summand

Definition at line 61 of file qwt_spline_polynomial.h.


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


plotjuggler
Author(s): Davide Faconti
autogenerated on Sat Jul 6 2019 03:44:19