Converts between velocities and frequencies. More...

#include <VelocityMachine.h>

Public Member Functions
	VelocityMachine (const MFrequency::Ref &freqRef, const Unit &freqUnits, const MVFrequency &restFreq, const MDoppler::Ref &velRef, const Unit &velUnits)
	Construct a machine from the input values (no frame conversion, implicit frame if necessary)
	VelocityMachine (const MFrequency::Ref &freqRef, const Unit &freqUnits, const MVFrequency &restFreq, const MDoppler::Ref &velRef, const Unit &velUnits, const MeasFrame &frame)
	Construct a machine from the input values (no frame conversion, explicit frame will be added to freqRef)
	VelocityMachine (const MFrequency::Ref &freqRef, const Unit &freqUnits, const MVFrequency &restFreq, const MFrequency::Types &convertRef, const MDoppler::Ref &velRef, const Unit &velUnits)
	Construct a machine from the input values (frame conversion, implicit frame assumed if necessary) with explicit velocity reference frame specified.
	VelocityMachine (const MFrequency::Ref &freqref, const Unit &freqUnits, const MVFrequency &restFreq, const MFrequency::Types &convertRef, const MDoppler::Ref &velRef, const Unit &velUnits, const MeasFrame &frame)
	Construct a machine from the input values (frame conversion, explicit frame) with explicit velocity reference frame specified, and added to freqref.
	VelocityMachine (const VelocityMachine &other)
	Copy constructor (copy semantics)
VelocityMachine &	operator= (const VelocityMachine &other)
	Copy assignment (copy semantics)
	~VelocityMachine ()
const Quantum< Double > &	operator() (const MVFrequency &in)
	Return velocity if frequency given, or a frequency if a velocity is given.
const Quantum< Double > &	operator() (const MVDoppler &in)
const Quantum< Double > &	operator() (const Quantum< Double > &in)
const Quantum< Double > &	makeVelocity (Double in)
const Quantum< Double > &	makeFrequency (Double in)
const Quantum< Vector< Double > > &	makeVelocity (const Vector< Double > &in)
const Quantum< Vector< Double > > &	makeFrequency (const Vector< Double > &in)
void	set (const MFrequency::Ref &in)
	Set or reset the specified part of the machine.
void	set (const Unit &in)
void	set (const MVFrequency &in)
	Sets the rest frequency.
void	set (const MFrequency::Types &in)
void	set (const MDoppler::Ref &in)
void	set (const MeasFrame &in)
	Sets the MeasFrame to be used in conversions.
const MFrequency::Ref &	getFrequencyReference () const
	Get the general information used in the machine (shadows the sets above and the constructor arguments.
const Unit &	getFrequencyUnits () const
const MDoppler::Ref &	getDopplerReference () const
const Unit &	getDopplerUnits () const
const MVFrequency &	getRestFrequency () const
const MFrequency::Types &	getConversionReference () const
void	reCalculate ()
	Recalculate the machinery from the original inputs.
Private Member Functions
	VelocityMachine ()
	Construct an empty machine (not implemented)
void	init ()
	Initialise machinery.
void	copy (const VelocityMachine &other)
	Copy data members.
Private Attributes
MFrequency::Ref	fref_p
	Frequency reference.
Unit	fun_p
	Frequency units.
MVFrequency	rest_p
	Rest frequency.
MFrequency::Types	vfm_p
	Velocity frame.
MDoppler::Ref	vref_p
	Velocity reference.
Unit	vun_p
	Velocity units.
Double	vfac_p
MFrequency::Convert	cvfv_p
	Frequency conversion forward.
MFrequency::Convert	cvvf_p
	Frequency conversion backward.
MDoppler::Convert	cvvo_p
	Velocity conversion forward.
MDoppler::Convert	cvov_p
	Velocity conversion backward.
Quantum< Double >	resv_p
	Result.
Quantum< Double >	resf_p
Quantum< Vector< Double > >	vresv_p
Quantum< Vector< Double > >	vresf_p

Detailed Description

Converts between velocities and frequencies.

Intended use:

Public interface

 <h3>Review Status</h3><dl><dt>Reviewed By:<dd>UNKNOWN<dt>Date Reviewed:<dd>before2004/08/25<dt>Test programs:<dd>tVelocityMachine</dl>

Prerequisite

Measures module
MFrequency class
MDoppler class

Etymology

From Velocity and machinery

Synopsis

The construction of a VelocityMachine class object creates a machine that can calculate the velocity from a frequency, or vice versa, a frequency from a velocity.

To be able to do the conversions, the machine (or rather its constructors) needs to know the following information:

Reference for frequencies. It should contain at least the reference code, to specify what type of frequency we are talking about (e.g. MFrequency::LSRK). The reference could also contain an offset. In that case all input frequencies are considered to be relative to this offset; all output frequencies will have this offset removed.
The reference can optionally contain a MeasFrame (which specifies where, when and in which direction you are observing). This frame is necessary if, in addition to converting between velocity and frequency, you also want to convert between different types (e.g. given an 'LSRK' velocity, you want to know the 'TOPO' frequency), and if the offset is in a different reference type. However, the MeasFrame can also be given explicitly in the machine constructor as an optional argument.
Preferred 'frequency' units (e.g. GHz, or cm). These units are used to output a frequency, or if an input frequency is given as a simple double, these units will be implicitly assumed.
Reference for velocity. It should contain at least the reference code, to specify what type of velocity we are talking about (e.g. MDoppler::OPTICAL, note that MDoppler::BETA is the 'true' velocity). The reference could also contain an offset. In that case all input velocities are considered to be relative to this offset; all output velocities will have this offset removed.
Preferred velocity units (e.g. AU/a). These units are used to output a velocity, or if an input velocity is given as a simple double, these units will be implicitly assumed.
The rest frequency to be used for converting between frequency and velocity. It is given as an MVFrequency.

To be able to convert between different types (say a velocity referenced with respect to the 'LSRK', and a frequency referenced with respect to 'TOPO', the following additional, optional information can be included explicitly in the constructors:

A reference code for the velocity (given as a frequency reference code (e.g. MFrequency::TOPO)). If given, all input frequencies will be converted to the frequency belonging to this reference code; all output frequencies will be converted from this assumed reference to the specified Frequency reference. The net effect is that all velocities will be assumed to refer to this reference code. Note that in most cases the conversion will have to know the 'when, where, which direction' environment (the 'frame' -- a MeasFrame). This can be given either implicitly in the 'reference for the frequency', or explicitly (see next dot point).
A frame (MeasFrame). This frame will be used in any conversion between reference frames. If not given explicitly here, it will tacitly be assumed that if a frame is necessary, it has been specified in the frequency reference.

Once the machine has been set up, operator() can be used to convert between velocities and frequencies if the input argument type (e.g. an MVFrequency) can be deduced. In other cases makeFrequency() or makeVelocity() should be used (e.g. if the argument type is a simple Double).

Example

        // Define a time/position frame
        MEpoch epo(MVEpoch(MVTime(98,5,16,0.5).day()));
        MPosition pos;
        MeasTable::Observatory(pos, "ATCA");
        MeasFrame frame(epo, pos);
        //
        // Note that e.g. the time in the frame can be changed later
        // Specify the frequency reference
        MFrequency::Ref fr(MFrequency::LSRK);
        //
        // Specify the velocity reference
        MDoppler::Ref vr(MDoppler::OPT);
        //
        // Specify the default units
        Unit fu("eV");
        Unit vu("AU/a");
        //
        // Get the rest frequency
        MVFrequency rfrq(QC::HI);
        //
        // Set up a machine (no conversion of reference frame)
        VelocityMachine exec(fr, fu, rfrq, vr, vu, frame);
        //
        // or as (with conversion of reference frame it could have been)
        // VelocityMachine exec(fr, fu, rfrq, vr, vu, MFrequency::TOPO, frame);
        // Given a current observational frequency of 5.87432837e-06 eV
        // its velocity will be (in AU/yr)
        cout << "Velocity: " << exec.makeVelocity(5.87432837e-06) << endl;
        //
        // Introducing an offset
        MFrequency foff(MVFrequency(Quantity(5.87432837e-06, "eV")),
                        MFrequency::LSRK);
        //
        // and setting it in the reference, and regenerating machine:
        fr.set(foff);
        exec.set(fr);
        //
        // the following will give the same result:
        cout << "Velocity: " << exec.makeVelocity(0.0) << endl;

See the test program for more examples

Motivation

To aid in converting series of frequencies and velocities

To Do

Nothing I know of

Definition at line 183 of file VelocityMachine.h.

Constructor & Destructor Documentation

casa::VelocityMachine::VelocityMachine	(	const MFrequency::Ref &	freqRef,
		const Unit &	freqUnits,
		const MVFrequency &	restFreq,
		const MDoppler::Ref &	velRef,
		const Unit &	velUnits
	)

Construct a machine from the input values (no frame conversion, implicit frame if necessary)

casa::VelocityMachine::VelocityMachine	(	const MFrequency::Ref &	freqRef,
		const Unit &	freqUnits,
		const MVFrequency &	restFreq,
		const MDoppler::Ref &	velRef,
		const Unit &	velUnits,
		const MeasFrame &	frame
	)

Construct a machine from the input values (no frame conversion, explicit frame will be added to freqRef)

casa::VelocityMachine::VelocityMachine	(	const MFrequency::Ref &	freqRef,
		const Unit &	freqUnits,
		const MVFrequency &	restFreq,
		const MFrequency::Types &	convertRef,
		const MDoppler::Ref &	velRef,
		const Unit &	velUnits
	)

Construct a machine from the input values (frame conversion, implicit frame assumed if necessary) with explicit velocity reference frame specified.

casa::VelocityMachine::VelocityMachine	(	const MFrequency::Ref &	freqref,
		const Unit &	freqUnits,
		const MVFrequency &	restFreq,
		const MFrequency::Types &	convertRef,
		const MDoppler::Ref &	velRef,
		const Unit &	velUnits,
		const MeasFrame &	frame
	)

Construct a machine from the input values (frame conversion, explicit frame) with explicit velocity reference frame specified, and added to freqref.

casa::VelocityMachine::VelocityMachine ( const VelocityMachine & other )

Copy constructor (copy semantics)

casa::VelocityMachine::~VelocityMachine ( )

casa::VelocityMachine::VelocityMachine ( ) [private]

Construct an empty machine (not implemented)

Member Function Documentation

void casa::VelocityMachine::copy ( const VelocityMachine & other ) [private]

Copy data members.

const MFrequency::Types& casa::VelocityMachine::getConversionReference ( ) const

const MDoppler::Ref& casa::VelocityMachine::getDopplerReference ( ) const

const Unit& casa::VelocityMachine::getDopplerUnits ( ) const

const MFrequency::Ref& casa::VelocityMachine::getFrequencyReference ( ) const

Get the general information used in the machine (shadows the sets above and the constructor arguments.

The MeasFrame should be explicitly asked for from the frequency reference by the user

const Unit& casa::VelocityMachine::getFrequencyUnits ( ) const

const MVFrequency& casa::VelocityMachine::getRestFrequency ( ) const

void casa::VelocityMachine::init ( ) [private]

Initialise machinery.

const Quantum<Double>& casa::VelocityMachine::makeFrequency ( Double in )

const Quantum<Vector<Double> >& casa::VelocityMachine::makeFrequency ( const Vector< Double > & in )

const Quantum<Double>& casa::VelocityMachine::makeVelocity ( Double in )

const Quantum<Vector<Double> >& casa::VelocityMachine::makeVelocity ( const Vector< Double > & in )

const Quantum<Double>& casa::VelocityMachine::operator() ( const MVFrequency & in )

Return velocity if frequency given, or a frequency if a velocity is given.

const Quantum<Double>& casa::VelocityMachine::operator() ( const MVDoppler & in )

const Quantum<Double>& casa::VelocityMachine::operator() ( const Quantum< Double > & in )

VelocityMachine& casa::VelocityMachine::operator= ( const VelocityMachine & other )

Copy assignment (copy semantics)

void casa::VelocityMachine::reCalculate ( )

Recalculate the machinery from the original inputs.

Note that in all normal circumstances this function does not have to be used (the set() methods will do it automatically). At the moment I cannot think of any circumstance it should be used explicitly.

void casa::VelocityMachine::set ( const MFrequency::Ref & in )

Set or reset the specified part of the machine.

The machinery will be reset to reflect the changes made.

Sets a new frequency reference. Note that if an explicit frame has been used in earlier constructors, the frame should again be set explicitly with set(MeasFrame).

void casa::VelocityMachine::set ( const Unit & in )