DP3 step reading from an MS. More...

#include <MsReader.h>

Inheritance diagram for dp3::steps::MsReader:

Public Member Functions
	MsReader (const casacore::MeasurementSet &ms, const common::ParameterSet &parset, const std::string &prefix, bool allow_missing_data=false)

void	addToMS (const std::string &) override

bool	AutoWeight () const

const std::string &	BaselineSelection () const
	Get the baseline selection. More...

const std::vector< std::string > &	ExtraDataColumnNames () const
	Get the names of the extra data columns that are also read. More...

void	finish () override
	Finish the processing of this step and subsequent steps. More...

void	getUVW (const casacore::RefRows &rowNrs, double time, base::DPBuffer &)
	Read the UVW at the given row numbers into the buffer. More...

bool	MissingData () const
	Is the data column missing? More...

std::string	msName () const override
	Get the name of the MS. More...

bool	process (std::unique_ptr< base::DPBuffer > buffer) override

void	show (std::ostream &) const override
	Show the step parameters. More...

void	showCounts (std::ostream &) const override
	If needed, show the flag counts. More...

void	showTimings (std::ostream &, double duration) const override
	Show the timings. More...

const casacore::Table &	table () const override
	Get the main MS table. More...

void	updateInfo (const base::DPInfo &) override
	Do nothing, since MsReader sets its info in the constructor. More...

Public Member Functions inherited from dp3::steps::InputStep
	~InputStep () override

const dp3::common::Fields &	getFieldsToRead () const
	Get which fields must be read. More...

common::Fields	getProvidedFields () const override

common::Fields	getRequiredFields () const override
	Get the fields required by the current step. More...

virtual void	setFieldsToRead (const dp3::common::Fields &fields)
	Set which fields must be read. More...

Public Member Functions inherited from dp3::steps::Step
	Step ()

virtual	~Step ()

virtual bool	accepts (MsType dt) const
	Boolean if this step can process this type of data. More...

const base::DPInfo &	getInfoIn () const
	Get access to the info of the input. More...

const base::DPInfo &	getInfoOut () const
	Get access to the info of the output. More...

const Step::ShPtr &	getNextStep () const
	Get the next step. More...

Step *	getPrevStep () const
	Get the previous step. More...

virtual MsType	outputs () const
	Return which datatype this step outputs. More...

virtual bool	process (std::unique_ptr< base::BdaBuffer >)

void	setInfo (const base::DPInfo &)

virtual void	setNextStep (Step::ShPtr nextStep)
	Set the next step. More...

void	setPrevStep (Step *prevStep)
	Set the previous step. More...

Static Public Member Functions
static void	FlagInfinityNan (base::DPBuffer &buffer, base::FlagCounter &flagCounter)
	Flags infinite and Not-a-Number values. More...

static std::pair< unsigned int, unsigned int >	ParseChannelSelection (const std::string &start_channel_string, const std::string &n_channels_string, unsigned int n_channels)

Static Public Member Functions inherited from dp3::steps::InputStep
static std::unique_ptr< InputStep >	CreateReader (const common::ParameterSet &)

static bool	HasBda (const casacore::MeasurementSet &ms)

Static Public Member Functions inherited from dp3::steps::Step
static void	SetThreadingIsInitialized ()

Additional Inherited Members
Public Types inherited from dp3::steps::Step
enum class	MsType { kRegular , kBda }
	To check compatibility between steps before running. More...

typedef std::shared_ptr< Step >	ShPtr

Static Public Attributes inherited from dp3::steps::Step
static constexpr dp3::common::Fields	kDataField

static constexpr dp3::common::Fields	kFlagsField

static constexpr dp3::common::Fields	kUvwField

static constexpr dp3::common::Fields	kWeightsField

Protected Member Functions inherited from dp3::steps::Step
base::DPInfo &	GetWritableInfoOut ()

Detailed Description

DP3 step reading from an MS.

This class is an InputStep step reading the data from a MeasurementSet. At the beginning it finds out the shape of the data; i.e., the number of correlations, channels, baselines, and time slots. It requires the data to be regularly shaped.

The object is constructed from the 'msin' keywords in the parset file. Currently the following can be given:

msin: name of the MS
msin.autoweight: calculate weights from autocorrelations? [no]
msin.startchan: first channel to use [0]
msin.nchan: number of channels to use [all]
msin.useflag: use the existing flags? [yes]
msin.datacolumn: the data column to use (measured visibilities) [DATA]
msin.extradatacolumns: the extra data columns to use. Could be used to load model visibilities when stored in the MS as well [empty]
msin.weightcolumn: the weights column to use [WEIGHT_SPECTRUM or WEIGHT]
msin.starttime: first time to use [first time in MS]
msin.endtime: last time to use [last time in MS]

If a time slot is missing, it inserts flagged data set to zero, i.e. it inserts dummy data that is marked invalid. Missing time slots can also be detected at the beginning or end of the MS by giving the correct starttime and endtime. The correct UVW coordinates are calculated for inserted time slots.

The process function reads the fields needed by the chain of steps which can be obtained calling getFieldsToRead(). In this way only the necessary data is kept in memory.

The data columns are handled in the following way:

TIME	The time slot center of the current data (in MJD seconds). It is assumed that all data have the same interval, which is used to find missing time slots.
DATA	The visibility data as [ncorr,nchan,nbaseline]. Only the part given by startchan and nchan is read. If a time slot is inserted, all its data are zero.
FLAG	The data flags as [ncorr,nchan,nbaseline] (True is bad). They are read from the FLAG column. If a FLAG_ROW is set, all flags for that baseline will be set. Also the flag of data containing NaN or infinite numbers will be set. All flags of an inserted time slot are set.
WEIGHT	The data weights as [ncorr,nchan,nbaseline]. Column WEIGHT_SPECTRUM is used if present and containing valid data, otherwise column WEIGHT is used. The weights of an inserted time slot are set to 0. If autoweight is on, the autocorrelations are used to calculate proper weights.
UVW	The UVW coordinates in meters as [3,nbaseline]. They are calculated for a missing time slot.

Constructor & Destructor Documentation

◆ MsReader()

dp3::steps::MsReader::MsReader	(	const casacore::MeasurementSet &	ms,
		const common::ParameterSet &	parset,
		const std::string &	prefix,
		bool	allow_missing_data = `false`
	)

Construct the object for the given MS. Parameters are obtained from the parset using the given prefix. The allow_missing_data argument is for MultiMsReader.

Member Function Documentation

◆ addToMS()

void dp3::steps::MsReader::addToMS ( const std::string & )

inlineoverridevirtual

Add some data to the MeasurementSet written/updated. Do nothing.

Reimplemented from dp3::steps::Step.

◆ AutoWeight()

bool dp3::steps::MsReader::AutoWeight ( ) const

inline

◆ BaselineSelection()

const std::string& dp3::steps::MsReader::BaselineSelection ( ) const

inline

Get the baseline selection.

◆ ExtraDataColumnNames()

const std::vector<std::string>& dp3::steps::MsReader::ExtraDataColumnNames ( ) const

inline

Get the names of the extra data columns that are also read.

◆ finish()

void dp3::steps::MsReader::finish ( )

overridevirtual

Finish the processing of this step and subsequent steps.

Implements dp3::steps::Step.

◆ FlagInfinityNan()

static void dp3::steps::MsReader::FlagInfinityNan	(	base::DPBuffer &	buffer,
		base::FlagCounter &	flagCounter
	)

static

Flags infinite and Not-a-Number values.

◆ getUVW()

void dp3::steps::MsReader::getUVW	(	const casacore::RefRows &	rowNrs,
		double	time,
		base::DPBuffer &
	)

Read the UVW at the given row numbers into the buffer.

◆ MissingData()

bool dp3::steps::MsReader::MissingData ( ) const

inline

Is the data column missing?

◆ msName()

std::string dp3::steps::MsReader::msName ( ) const

overridevirtual

Get the name of the MS.

Reimplemented from dp3::steps::InputStep.

◆ ParseChannelSelection()

static std::pair<unsigned int, unsigned int> dp3::steps::MsReader::ParseChannelSelection	(	const std::string &	start_channel_string,
		const std::string &	n_channels_string,
		unsigned int	n_channels
	)

static

Parse the expressions for the start channel and number of channels. The total number of channels can be used as 'nchan' in both expressions.

◆ process()

bool dp3::steps::MsReader::process ( std::unique_ptr< base::DPBuffer > buffer )

overridevirtual

Process the next data chunk. It returns false when at the end.

Reimplemented from dp3::steps::Step.

◆ show()

void dp3::steps::MsReader::show ( std::ostream & ) const

overridevirtual

Show the step parameters.

Implements dp3::steps::Step.

◆ showCounts()

void dp3::steps::MsReader::showCounts ( std::ostream & ) const

overridevirtual

If needed, show the flag counts.

Reimplemented from dp3::steps::Step.

◆ showTimings()

void dp3::steps::MsReader::showTimings	(	std::ostream &	,
		double	duration
	)		const

overridevirtual

Show the timings.

Reimplemented from dp3::steps::Step.

◆ table()

const casacore::Table& dp3::steps::MsReader::table ( ) const

inlineoverridevirtual

Get the main MS table.

Reimplemented from dp3::steps::InputStep.

◆ updateInfo()

void dp3::steps::MsReader::updateInfo ( const base::DPInfo & )

inlineoverridevirtual

Do nothing, since MsReader sets its info in the constructor.

Reimplemented from dp3::steps::Step.

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

MsReader.h

Public Member Functions

Static Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ MsReader()

Member Function Documentation

◆ addToMS()

◆ AutoWeight()

◆ BaselineSelection()

◆ ExtraDataColumnNames()

◆ finish()

◆ FlagInfinityNan()

◆ getUVW()

◆ MissingData()

◆ msName()

◆ ParseChannelSelection()

◆ process()

◆ show()

◆ showCounts()

◆ showTimings()

◆ table()

◆ updateInfo()