Aligns spectra in frequency space. More...

#include <FrequencyAligner.h>

Public Member Functions
	FrequencyAligner ()
	Default constructor (object not viable)
	FrequencyAligner (const SpectralCoordinate &specCoord, uInt nPixels, const MEpoch &refEpoch, const MDirection &dir, const MPosition &pos, MFrequency::Types freqSystem)
	Constructor specifies a SpectralCoordinate (any extra reference conversion frame set in it will be ignored), the number of pixels in the spectra to be aligned, a reference epoch to which all spectra will be aligned, a direction on the sky, a position on the earth (the observatory), and desired frequency system to align in.
	FrequencyAligner (const FrequencyAligner< T > &other)
	Copy constructor (copy semantics)
FrequencyAligner &	operator= (const FrequencyAligner< T > &other)
	Assignment (copy semantics)
	~FrequencyAligner ()
	Destructor.
void	setTolerance (Double tol)
	Set a tolerance (in pixels) to trigger regridding (function `align`).
Bool	align (Vector< T > &yOut, Vector< Bool > &maskOut, const Vector< T > &yIn, const Vector< Bool > &maskIn, const MEpoch &epoch, Bool useCachedAbcissa, typename InterpolateArray1D< Double, T >::InterpolationMethod method, Bool extrapolate=False)
	Align (via regridding) one spectrum taken at the specified epoch to the reference epoch.
Bool	align (Vector< T > &yOut, Vector< Bool > &maskOut, const Vector< Double > &xIn, const Vector< T > &yIn, const Vector< Bool > &maskIn, const MEpoch &epoch, Bool useCachedAbcissa, typename InterpolateArray1D< Double, T >::InterpolationMethod method, Bool extrapolate=False)
	This function is the same as the previous except that you can specify the input abcissa as well as the data and mask.
Bool	alignMany (Array< T > &yOut, Array< Bool > &maskOut, const Array< T > &yIn, const Array< Bool > &maskIn, uInt axis, const MEpoch &epoch, typename InterpolateArray1D< Double, T >::InterpolationMethod method, Bool extrapolate=False)
	Align many spectra stored in an Array along the specified axis.
void	getReferenceAbcissa (Vector< Double > &xOut) const
	Get the reference abcissa (as a frequency in the axis units set in the SpectralCoordinate) at the reference epoch.
void	getAbcissa (Vector< Double > &xOut) const
	Get the abcissa (as a frequency in the axis units set in the SpectralCoordinate) last cached by function `align`
SpectralCoordinate	alignedSpectralCoordinate (Bool doLinear=True) const
	Get new aligned SpectralCoordinate.
Private Member Functions
void	copyOther (const FrequencyAligner< T > &other)
	Internal copy.
void	makeMachine (const MEpoch &refEpoch, const MDirection &dir, const MPosition &pos, MFrequency::Types freqSystem, const Unit &unit)
	Create the Conversion machine.
Double	makeAbcissa (Vector< Double > &f, Bool doMaxDiff)
	Generate an abcissa with the machine.
Bool	regrid (Vector< T > &yOut, Vector< Bool > &maskOut, const Vector< Double > &xOut, const Vector< Double > &xIn, const Vector< T > &yIn, const Vector< Bool > &maskIn, typename InterpolateArray1D< Double, T >::InterpolationMethod method, Bool extrapolate, Double maxDiff) const
	Regrid one spectrum.
Private Attributes
SpectralCoordinate	itsSpecCoord
MFrequency::Convert	itsMachine
MFrequency::Ref	itsRefOut
MFrequency::Types	itsFreqSystem
	the conversion machines epoch otherwise
Vector< Double >	itsRefFreqX
Vector< Double >	itsFreqX
Double	itsDiffTol

Detailed Description

template<class T>
class casa::FrequencyAligner< T >

Aligns spectra in frequency space.

Intended use:

Public interface

Review Status

Test programs:: tFrequencyAligner

Prerequisite

Synopsis

Spectra are converted to the specified reference frame and aligned at a specified instant in time.

You should not try to convert from, say, a SpectralCoordinate::TOPO to MFrequency::TOPO as this would be meaningless. This class is designed mainly to convert say from a SpectralCoordinate::TOPO to say, a BARY frame and align.

Motivation

Required for ASAP single-dish package

Definition at line 81 of file FrequencyAligner.h.

Constructor & Destructor Documentation

template<class T>

casa::FrequencyAligner< T >::FrequencyAligner ( )

Default constructor (object not viable)

template<class T>

casa::FrequencyAligner< T >::FrequencyAligner	(	const SpectralCoordinate &	specCoord,
		uInt	nPixels,
		const MEpoch &	refEpoch,
		const MDirection &	dir,
		const MPosition &	pos,
		MFrequency::Types	freqSystem
	)

Constructor specifies a SpectralCoordinate (any extra reference conversion frame set in it will be ignored), the number of pixels in the spectra to be aligned, a reference epoch to which all spectra will be aligned, a direction on the sky, a position on the earth (the observatory), and desired frequency system to align in.

template<class T>

casa::FrequencyAligner< T >::FrequencyAligner ( const FrequencyAligner< T > & other )

Copy constructor (copy semantics)

template<class T>

casa::FrequencyAligner< T >::~FrequencyAligner ( )

Destructor.

Member Function Documentation

template<class T>

Bool casa::FrequencyAligner< T >::align	(	Vector< T > &	yOut,
		Vector< Bool > &	maskOut,
		const Vector< T > &	yIn,
		const Vector< Bool > &	maskIn,
		const MEpoch &	epoch,
		Bool	useCachedAbcissa,
		typename InterpolateArray1D< Double, T >::InterpolationMethod	method,
		Bool	extrapolate = `False`
	)

Align (via regridding) one spectrum taken at the specified epoch to the reference epoch.

Your provide the ordinate and mask (True==Good) for the spectrum. The lengths of these vectors must be the same as nPixels given in the constructor. The output vectors are resized as needed. You can use the last cached abcissa (computed by this function) rather than recompute it if you have more than one spectrum at the same epoch to convert (e.g. different polarizations). If you do this, it is your responsibility to make sure that you have called this function at least once with useCachedAbcissa=False. If extrapolate is True, the regridding process is allowed to extrapolate outside of the abcissa domain. Otherwise masked pixels will result. Returns True if a regrid triggered, else False if just copied (see function setTolerance.

template<class T>

Bool casa::FrequencyAligner< T >::align	(	Vector< T > &	yOut,
		Vector< Bool > &	maskOut,
		const Vector< Double > &	xIn,
		const Vector< T > &	yIn,
		const Vector< Bool > &	maskIn,
		const MEpoch &	epoch,
		Bool	useCachedAbcissa,
		typename InterpolateArray1D< Double, T >::InterpolationMethod	method,
		Bool	extrapolate = `False`
	)

This function is the same as the previous except that you can specify the input abcissa as well as the data and mask.

The input abcissa must be in the same units as the Construction SpectralCoordinate. The abcissa values must be in the same base reference frame as the Construction SpectralCoordinate. So instead of the abcissa (in the output reference frame) being computed from the Construction SC, you get to specify the abcissa directly. This might be useful if you have more than one set of spectra to align, all in the same Frame, but with different attributes such as reference value/pixel etc. The output spectrum is still regridded to the abcissa at the reference time generated at construction. from the current

template<class T>

SpectralCoordinate casa::FrequencyAligner< T >::alignedSpectralCoordinate ( Bool doLinear = True ) const

Get new aligned SpectralCoordinate.

It is probably non-linear, but if you would like a linear approximation, use the doLinear argument.

template<class T>

Bool casa::FrequencyAligner< T >::alignMany	(	Array< T > &	yOut,
		Array< Bool > &	maskOut,
		const Array< T > &	yIn,
		const Array< Bool > &	maskIn,
		uInt	axis,
		const MEpoch &	epoch,
		typename InterpolateArray1D< Double, T >::InterpolationMethod	method,
		Bool	extrapolate = `False`
	)

Align many spectra stored in an Array along the specified axis.

All spectra are aligned to the same frequency abcissa (as described in previous function). If any alignment returns False, then the return value will be False, otherwise True is returned.

template<class T>

void casa::FrequencyAligner< T >::copyOther ( const FrequencyAligner< T > & other ) [private]

Internal copy.

template<class T>

void casa::FrequencyAligner< T >::getAbcissa ( Vector< Double > & xOut ) const

Get the abcissa (as a frequency in the axis units set in the SpectralCoordinate) last cached by function align

template<class T>

void casa::FrequencyAligner< T >::getReferenceAbcissa ( Vector< Double > & xOut ) const

Get the reference abcissa (as a frequency in the axis units set in the SpectralCoordinate) at the reference epoch.

template<class T>

Double casa::FrequencyAligner< T >::makeAbcissa	(	Vector< Double > &	f,
		Bool	doMaxDiff
	)		`[private]`

Generate an abcissa with the machine.

template<class T>

void casa::FrequencyAligner< T >::makeMachine	(	const MEpoch &	refEpoch,
		const MDirection &	dir,
		const MPosition &	pos,
		MFrequency::Types	freqSystem,
		const Unit &	unit
	)		`[private]`

Create the Conversion machine.

template<class T>

FrequencyAligner& casa::FrequencyAligner< T >::operator= ( const FrequencyAligner< T > & other )

Assignment (copy semantics)

template<class T>

Bool casa::FrequencyAligner< T >::regrid	(	Vector< T > &	yOut,
		Vector< Bool > &	maskOut,
		const Vector< Double > &	xOut,
		const Vector< Double > &	xIn,
		const Vector< T > &	yIn,
		const Vector< Bool > &	maskIn,
		typename InterpolateArray1D< Double, T >::InterpolationMethod	method,
		Bool	extrapolate,
		Double	maxDiff
	)		const `[private]`

Regrid one spectrum.

template<class T>

void casa::FrequencyAligner< T >::setTolerance ( Double tol ) [inline]

Set a tolerance (in pixels) to trigger regridding (function align).

If the maximum abcissa difference for the current spectrum abcissa compared to the reference abcissa is greater than tol (pixels) then a regrid is triggered. Otherwise the input is just copied to the output when function align is called. Set to 0 to turn this tolerance assessment off. This function may be not really worth using.

Definition at line 112 of file FrequencyAligner.h.

References casa::abs(), and casa::FrequencyAligner< T >::itsDiffTol.