Referencia de la Clase QwtSpline

A class for spline interpolation. Más...

#include <qwt_spline.h>

Lista de todos los miembros.

Clases
class	PrivateData
Tipos públicos
enum	SplineType { Natural, Periodic }
Métodos públicos
	QwtSpline ()
	Constructor.
	QwtSpline (const QwtSpline &)
	~QwtSpline ()
	Destructor.
QwtSpline &	operator= (const QwtSpline &)
void	setSplineType (SplineType)
SplineType	splineType () const
bool	setPoints (const QwtArray< QwtDoublePoint > &points)
	Determine the function table index corresponding to a value x.
QwtArray< QwtDoublePoint >	points () const
void	reset ()
	Free allocated memory and set size to 0.
bool	isValid () const
	True if valid.
double	value (double x) const
Métodos protegidos
bool	buildNaturalSpline (const QwtArray< QwtDoublePoint > &)
	Determines the coefficients for a natural spline.
bool	buildPeriodicSpline (const QwtArray< QwtDoublePoint > &)
	Determines the coefficients for a periodic spline.
Atributos protegidos
PrivateData *	d_data

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Descripción detallada

A class for spline interpolation.

The QwtSpline class is used for cubical spline interpolation. Two types of splines, natural and periodic, are supported.

Usage:

1. First call setPoints() to determine the spline coefficients for a tabulated function y(x).
2. After the coefficients have been set up, the interpolated function value for an argument x can be determined by calling QwtSpline::value().

Example:

#include <qwt_spline.h>

QPolygonF interpolate(const QPolygonF& points, int numValues)
{
    QwtSpline spline;
    if ( !spline.setPoints(points) ) 
        return points;

    QPolygonF interpolatedPoints(numValues);

    const double delta = 
        (points[numPoints - 1].x() - points[0].x()) / (points.size() - 1);
    for(i = 0; i < points.size(); i++)  / interpolate
    {
        const double x = points[0].x() + i * delta;
        interpolatedPoints[i].setX(x);
        interpolatedPoints[i].setY(spline.value(x));
    }
    return interpolatedPoints;
}

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Documentación de las enumeraciones miembro de la clase

enum QwtSpline::SplineType

Valores de enumeraciones:

Natural
Periodic

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Documentación del constructor y destructor

QwtSpline::QwtSpline

(

)

Constructor.

QwtSpline::QwtSpline

(

const QwtSpline &

other

)

QwtSpline::~QwtSpline

(

)

Destructor.

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Documentación de las funciones miembro

bool QwtSpline::buildNaturalSpline

(

const QwtArray< QwtDoublePoint > &

points

)

[protected]

Determines the coefficients for a natural spline.

Devuelve:

true if successful

bool QwtSpline::buildPeriodicSpline

(

const QwtArray< QwtDoublePoint > &

points

)

[protected]

Determines the coefficients for a periodic spline.

Devuelve:

true if successful

bool QwtSpline::isValid

(

void

)

const

True if valid.

QwtSpline & QwtSpline::operator=

(

const QwtSpline &

other

)

QwtArray< QwtDoublePoint > QwtSpline::points

(

)

const

Return points passed by setPoints

void QwtSpline::reset

(

void

)

Free allocated memory and set size to 0.

bool QwtSpline::setPoints

(

const QwtArray< QwtDoublePoint > &

points

)

Determine the function table index corresponding to a value x.

Calculate the spline coefficients

Depending on the value of periodic, this function will determine the coefficients for a natural or a periodic spline and store them internally.

Parámetros:

x
y	points
size	number of points
periodic	if true, calculate periodic spline

Devuelve:

true if successful

Atención:

The sequence of x (but not y) values has to be strictly monotone increasing, which means x[0] < x[1] < .... < x[n-1]. If this is not the case, the function will return false

void QwtSpline::setSplineType

(

SplineType

splineType

)

QwtSpline::SplineType QwtSpline::splineType

(

)

const

double QwtSpline::value

(

double

x

)

const

Calculate the interpolated function value corresponding to a given argument x.

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Documentación de los datos miembro

PrivateData* QwtSpline::d_data [protected]

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La documentación para esta clase fue generada a partir de los siguientes ficheros:

• src/qwt/src/qwt_spline.h
• src/qwt/src/qwt_spline.cpp