FrequencyAligner.h

Classes

FrequencyAligner -- Aligns spectra in frequency space (full description)

template <class T> class FrequencyAligner

Interface

Public Members
FrequencyAligner()
FrequencyAligner(const SpectralCoordinate& specCoord, uInt nPixels, const MEpoch& refEpoch, const MDirection& dir, const MPosition& pos, MFrequency::Types freqSystem)
FrequencyAligner (const FrequencyAligner<T>& other)
FrequencyAligner& operator=(const FrequencyAligner<T>& other)
~FrequencyAligner()
void setTolerance (Double tol)
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)
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)
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)
void getReferenceAbcissa (Vector<Double>& xOut) const
void getAbcissa (Vector<Double>& xOut) const
SpectralCoordinate alignedSpectralCoordinate (Bool doLinear=True) const
Private Members
void copyOther (const FrequencyAligner<T>& other)
void makeMachine (const MEpoch& refEpoch, const MDirection& dir, const MPosition& pos, MFrequency::Types freqSystem, const Unit& unit)
Double makeAbcissa (Vector<Double>& f, Bool doMaxDiff)
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

Description

Review Status

Programs:
Tests:

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

To Do

Member Description

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). 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.

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. 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.

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. 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

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. 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.

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

void copyOther (const FrequencyAligner<T>& other)

Tolerance which triggers a regrid

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