casa::Lorentzian1DParam< T > Class Template Reference

Parameter handling for one dimensional Lorentzian class. More...

#include <Lorentzian1DParam.h>

Inheritance diagram for casa::Lorentzian1DParam< T >:

List of all members.

Public Types
enum	{   HEIGHT,   CENTER,   WIDTH }
Public Member Functions
	Lorentzian1DParam ()
	Constructs the one dimensional Lorentzians.
	Lorentzian1DParam (const T &height)
	Lorentzian1DParam (const T &height, const T &center)
	Lorentzian1DParam (const T &height, const T &center, const T &width)
	Lorentzian1DParam (const Lorentzian1DParam< T > &other)
	Copy constructor (deep copy)
template<class W >
	Lorentzian1DParam (const Lorentzian1DParam< W > &other)
Lorentzian1DParam< T > &	operator= (const Lorentzian1DParam< T > &other)
	Copy assignment (deep copy)
virtual	~Lorentzian1DParam ()
	Destructor.
virtual const String &	name () const
	Give name of function.
T	height () const
	Get or set the peak height of the Lorentzian.
void	setHeight (const T &height)
T	flux () const
	Get or set the analytical integrated area underneath the Lorentzian.
void	setFlux (const T &flux)
T	center () const
	Get or set the center ordinate of the Lorentzian.
void	setCenter (const T &cnter)
T	width () const
	Get or set the FWHM of the Lorentzian.
void	setWidth (const T &width)
Protected Attributes
T	fwhm2int

---

Detailed Description

template<class T>
class casa::Lorentzian1DParam< T >

Parameter handling for one dimensional Lorentzian class.

Intended use:

Internal

Review Status

Reviewed By:

tcornwel

Date Reviewed:

1996/02/22

Test programs:

tLorentzian1D

Prerequisite

• FunctionParam class
• Function1D class

Etymology

A 1-dimensional Lorentzian's parameters.

Synopsis

A Lorentzian1D is described by a height, center, and width. The parameters (height, center and width) may be changed at run time.

The width of the Lorentzian (for the constructors or the setWidth function) is always specified in terms of the full width at half maximum (FWHM). It is always positive and attempts to set a non-positive width will throw an assertion when in debug mode.

The peak height of the Lorentzian can be specified at construction time or by using the setHeight function. Alternatively the setFlux function can be used to implicitly set the peak height by specifying the integrated area under the Lorentzian. The height (or flux) can be positive, negative or zero, as this class makes no assumptions on what quantity the height represents.

Tip: Changing the width of the Lorentzian will not affect its peak height but will change its flux; So you should always set the width before setting the flux;

The parameter interface (see FunctionParam class), is used to provide an interface to the Fitting classes.

There are 3 parameters that are used to describe the Lorentzian:

1. The height of the Lorentzian. This is identical to the value returned using the height() member function.
2. The center of the Lorentzian in the x direction. This is identical to the value returned using the center() member function.
3. The width (FWHM) of the Lorentzian. To aid convergence of the non-linear fitting routines this parameter is allowed to be negative. This does not affect the shape of the Lorentzian as the square of the width is used when evaluating the function.

An enumeration for the HEIGHT, WIDTH and CENTER parameter index is provided, enabling the setting and reading of parameters with the [] operator. The mask() methods can be used to check and set the parameter masks.

This class is in general used implicitly by the Lorentzian1D class only.

Example

       Lorentzian1D<Double> gf(5.0, 25.0, 7);
       gf(25);            // = 5.0
       gf.setHeight(1.0);
       gf[WIDTH](2.0);                
       gf[CENTER](0.0);
       gf(1);             // = 0.5*height = 0.5

Template Type Argument Requirements (T)

• T should have standard numerical operators and exp() function. Current implementation only tested for real types (and their AutoDiffs).

Thrown Exceptions

• Assertion in debug mode if attempt is made to set a negative width
• AipsError if incorrect parameter number specified.

To Do

• Lorentzians that know about their DFT's could be required eventually.

Definition at line 128 of file Lorentzian1DParam.h.

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Member Enumeration Documentation

template<class T>

anonymous enum

Enumerator:

HEIGHT
CENTER
WIDTH

Definition at line 131 of file Lorentzian1DParam.h.

---

Constructor & Destructor Documentation

template<class T>

casa::Lorentzian1DParam< T >::Lorentzian1DParam

(

)

Constructs the one dimensional Lorentzians.

Defaults: height=1, center=0, width(FWHM)=1.
Warning: Could not use default arguments that worked both with gcc and IRIX and all templates

template<class T>

casa::Lorentzian1DParam< T >::Lorentzian1DParam

(

const T &

height

)

[explicit]

template<class T>

casa::Lorentzian1DParam< T >::Lorentzian1DParam	(	const T &	height,
		const T &	center
	)

template<class T>

casa::Lorentzian1DParam< T >::Lorentzian1DParam	(	const T &	height,
		const T &	center,
		const T &	width
	)

template<class T>

casa::Lorentzian1DParam< T >::Lorentzian1DParam

(

const Lorentzian1DParam< T > &

other

)

Copy constructor (deep copy)

template<class T>

template<class W >

casa::Lorentzian1DParam< T >::Lorentzian1DParam

(

const Lorentzian1DParam< W > &

other

)

[inline]

Definition at line 149 of file Lorentzian1DParam.h.

template<class T>

virtual casa::Lorentzian1DParam< T >::~Lorentzian1DParam

(

)

[virtual]

Destructor.

---

Member Function Documentation

template<class T>

T casa::Lorentzian1DParam< T >::center

(

)

const [inline]

Get or set the center ordinate of the Lorentzian.

Definition at line 181 of file Lorentzian1DParam.h.

template<class T>

T casa::Lorentzian1DParam< T >::flux

(

)

const

Get or set the analytical integrated area underneath the Lorentzian.

Use these functions as an alternative to the height functions.

template<class T>

T casa::Lorentzian1DParam< T >::height

(

)

const [inline]

Get or set the peak height of the Lorentzian.

Definition at line 168 of file Lorentzian1DParam.h.

Referenced by casa::Lorentzian1DParam< AutoDiff< T > >::setHeight().

template<class T>

virtual const String& casa::Lorentzian1DParam< T >::name

(

)

const [inline, virtual]

Give name of function.

Reimplemented from casa::Function< T, T >.

Definition at line 163 of file Lorentzian1DParam.h.

template<class T>

Lorentzian1DParam<T>& casa::Lorentzian1DParam< T >::operator=

(

const Lorentzian1DParam< T > &

other

)

Copy assignment (deep copy)

template<class T>

void casa::Lorentzian1DParam< T >::setCenter

(

const T &

cnter

)

[inline]

Definition at line 182 of file Lorentzian1DParam.h.

template<class T>

void casa::Lorentzian1DParam< T >::setFlux

(

const T &

flux

)

template<class T>

void casa::Lorentzian1DParam< T >::setHeight

(

const T &

height

)

[inline]

Definition at line 169 of file Lorentzian1DParam.h.

template<class T>

void casa::Lorentzian1DParam< T >::setWidth

(

const T &

width

)

[inline]

Definition at line 188 of file Lorentzian1DParam.h.

template<class T>

T casa::Lorentzian1DParam< T >::width

(

)

const [inline]

Get or set the FWHM of the Lorentzian.

Definition at line 187 of file Lorentzian1DParam.h.

Referenced by casa::Lorentzian1DParam< AutoDiff< T > >::setWidth().

---

Member Data Documentation

template<class T>

T casa::Lorentzian1DParam< T >::fwhm2int [protected]

Constant to scale halfwidth at 1/e to FWHM static const T fwhm2int;

Definition at line 188 of file Lorentzian1DParam.h.

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

• casacore/scimath/Functionals/Lorentzian1DParam.h