SimSource.h

This container describes the sources that are to be observed in a set of simulated observations. It provides a simpler (subset) representation of a source than what is allowed in the MS SOURCE table. This container is used to define simulated observations. Simulators would not normally create these objects directly but rather implicitly via the SimObservations class.

For far-field, non-moving objects, one sets the description at construction time with an object name, direction, and, optionally, a code and associated spectral window ID. This data cannot be changed later. One can later set a time stamp and interval if the source is moving, and/or a distance if it is in the near-field. It is intended that this latter extended data would be set once and not changed (particularly after the data have been flushed to disk).

Motivation

This container provides an simplified in-memory representation of feeds that will ultimately be written to a SOURCE table. The interface is oriented toward what is typical with current instruments and thus is simpler than the interface provided by the MS SOURCE table.

To Do

It would probably be helpful to have a common base classes for all Sim* and Sim*List classes that are managed by SimTelescope and SimObservations

Member Description

SimSource(const String& name, const MDirection& dir, const String& code="", Int spWinId=-1)

Create a record name is the name of the source. dir is the direction to the source code is an optional classification of the source in terms of the role it plays in data processing (see the MS2 spec's defintion of the SOURCE table for details). spWinId is an associated spectral window ID. If set to -1, the source is associated with all windows.

SimSource(const SimSource& that)
SimSource& operator=(const SimSource& that)

create a copy

Int getRow() const
void setRow(Int id)

get and set the row ID, the row in the SOURCE table containing this record. An ID less than zero means that this record has not yet been recorded.

Int getId() const
void setId(Int id)

get and set the SOURCE_ID. An ID less than zero means that it will be set to the row ID when it is recorded in the SOURCE table

const String &name() const

return the source name

const MDirection& direction() const

return the direction to the source

const String& code() const

return the role code for this source

void setTime(MEpoch t)

set the mid-point of the time interval for which this source description is valid.

const MEpoch& time() const
const Double timeSec() const

return the mid-point of the time interval for which this source description is valid. If interval() is < 0, then this time represents the starting time. The default time is 0s. timesec() returns the time in seconds and, thus, is more convenient for determining if the time has been set from its default.

Double interval() const

return the time interval for which this source description is valid. If the interval is < 0, then this description is valid until the starting time of the next record.

void setInterval(Quantity intv)
void setIntervalSec(Double intv)

set the time interval for which this source description is valid. If the interval is < 0, then this description is valid until the starting time of the next record.

Int spectralWindow() const

return the spectral window associated with this source. A value less than 0 refers to all windows.

Quantity distance() const
Double distancekm() const
void setDistance(const Quantity& dist)
void setDistancekm(Double dist)

get and the distance to the source. If <= 0.0, the distance is taken to be in the far-field (default). The units on the value returned by distancekm() is kilometers.

class SimSourceList

Interface

SimSourceList(uInt initsz=2, uInt stepsz=4) : n_p(0), chnk_p(stepsz), rec_p(initsz, 0)

SimSourceList(const MSSource& srct, uInt stepz=4)

SimSourceList(const SimSourceList& t)

SimSourceList& operator=(const SimSourceList& t)

~SimSourceList()

void clearIds()

SimSource& operator[](Int i)

const SimSource& operator[](Int i) const

Int numSources() const

SimSource& addSource(const String& name, const MDirection& dir, const String& code="", Int spWinId=-1)

void initFrom(const MSSource& srct)

void flush(MSSource& srct)

Private Members

void deleteRecs()

SimSource& get(Int i) const

void throwOutOfRange(uInt legallength, Int index) const

void add(SimSource *src)

Description

Prerequisite

Etymology

This class holds a list of SimSource objects.

Synopsis

This class holds a list of SimSource instances which, as a group, describes a list of sources to observe. When using this class, one does not create SimSource objects directly, but rather implicitly via the addSource() function. The ultimate purpose of this container is to support simulated observations. Simulators would not normally create these objects directly but rather implicitly via the SimObservations class.

An important function handled by this class is the recording of the data descriptiosn to a Measurement Set. This is done with the flush() function. When it writes the data from a SimSource in its list to the MS, it sets the row number of the source record via setRow(); this is used as a flag indicating that the SimSource as been flushed. This allows one to later add additional setups to the list; when flush() is called again, only the new SimSource data are written out. This, of course, assumes that the same output MSSource is passed to the flush() function each time. If you want to write all the data to a new SOURCE table, you can call clearIds() to clear all the row markers.

A list of polarization setups can be read in from a SOURCE table as well using the initFrom() method or the SimSourceList(const MSSource&, ...) constructor. These will implicitly set the row markers from the input table. This allows one to add new setups to the already recorded set.

Motivation

This container provides an simplified in-memory representation of sources that will ultimately be written to a SOURCE table. The interface is oriented toward what is typical with current instruments and thus is simpler than the interface provided by the MS SOURCE table.

To Do

loading from an existing MS needs more testing.
It would probably be helpful to have a common base classes for all Sim* and Sim*List classes that are managed by SimTelescope and SimObservations

Member Description

SimSourceList(uInt initsz=2, uInt stepsz=4) : n_p(0), chnk_p(stepsz), rec_p(initsz, 0)

create an empty list

SimSourceList(const MSSource& srct, uInt stepz=4)

create a list and fill it with the contents of a SOURCE table

SimSourceList(const SimSourceList& t)
SimSourceList& operator=(const SimSourceList& t)

create a copy

~SimSourceList()

void clearIds()

reset all the row markers used to flag the SimSource members that have been recorded to a Measurement Set already. Thus, the next call to flush() will record all SimPols to the SOURCE table. This should be used when writing to a new SOURCE table, different from one previously read from or written to.

SimSource& operator[](Int i)
const SimSource& operator[](Int i) const

access the i-th source description in this list.

Int numSources() const

return the number of sources in this list

SimSource& addSource(const String& name, const MDirection& dir, const String& code="", Int spWinId=-1)

Create a source description. name is the name of the source. dir is the direction to the source code is an optional classification of the source in terms of the role it plays in data processing (see the MS2 spec's defintion of the SOURCE table for details). spWinId is an associated spectral window ID. If set to -1, the source is associated with all windows.