VLAADA Class Reference

Interprets the data in an antenna data area of a VLA logical record. More...

#include <VLAADA.h>

List of all members.

Public Member Functions
	VLAADA ()
	The default constructor creates a unusable object.
	VLAADA (ByteSource &record, uInt offset)
	Construct this object to read data from the specified VLA logical record.
	~VLAADA ()
	The destructor is trivial.
	VLAADA (const VLAADA &other)
	The copy constructor uses reference semantics.
VLAADA &	operator= (const VLAADA &other)
	The assignment constructor uses reference semantics.
void	attach (ByteSource &record, uInt offset)
	Re-initialise this object so that it now reads data from the given VLA logical record.
String	antName (Bool newStyle=True) const
	return the antenna name.
uInt	antId () const
	returns the antenna Id.
Float	frontEndTemp (VLAEnum::IF which) const
	Front end Temp...gives a clue if antenna is EVLA.
String	padName () const
	return the pad name that this antenna is currently located on.
Double	u () const
	return the u coordinate in meters of this antenna at the centre of the integration.
Double	v () const
	return the v coordinate in meters of this antenna at the centre of the integration.
Double	w () const
	return the w coordinate in meters of this antenna at the centre of the integration.
Double	bx () const
	return the Bx position in meters of this antenna, from the centre of the Array.
Double	by () const
	return the By position in meters of this antenna, from the centre of the Array.
Double	bz () const
	return the Bz position in meters of this antenna, from the centre of the Array.
Vector< Double >	pos () const
	return the bx, by, bz positions in meters of this antenna, from the centre of the Array.
uInt	ifStatus (VLAEnum::IF which) const
	return the IF status.
Float	nominalSensitivity (VLAEnum::IF which) const
	returns the nominal sensitivity of the specified IF.
Stokes::StokesTypes	ifPol (VLAEnum::IF which) const
	return the IF polarisation.
Bool	nomSensApplied (VLAEnum::IF which, const uInt rev) const
	Has the nominal sensitivity amplitude scaling been applied? (auto-True prior to revision 25 [exclusive])
String	arrayName () const
	Identifies which array an antennn belongs to: VLA, EVLA, or VLBA.
Bool	ok () const
	Function which checks the internal data of this class for consistant values.
Private Attributes
ByteSource	itsRecord
uInt	itsOffset

---

Detailed Description

Interprets the data in an antenna data area of a VLA logical record.

Intended use:

Public interface

Review Status

Date Reviewed:

yyyy/mm/dd

Prerequisite

• The VLA archive format as described in VLA computer memo 188

Etymology

The antenna data is, in memo 188, frequently shortened to the acronym ADA. As this is specific to the VLA the name VLAADA seemed appropriate.

Synopsis

This class contains functions which access and interpret the data in an antenna data area of a VLA logical record. Only data within one antenna data are is accessable with this class, and multiple instances of this class are needed to simultaneously look at the data in the other antenna data areas in a VLA logical record.

The functions in this class access the specified data in the antenna data area, and may convert the units and data types so something more suitable for general use. They also interpret the data and provide some derived quantities eg., the padName function.

Example

This code fragment shows how to initialise a Block of objects of this class and then use these objects to determine which antenna is on which pad. It is assumed that the Bytesource object contains a VLA Logical record.

      ByteSource VLARecord(...);
      Block<VLAADA> adaBlock;
      VLARCA rca(VLARecord);
      const uInt nant = rca.nAntennas();
      adaBlock.resize(nant);
      for (uInt a = 0; a < nant; a++) {
        adaBlock[a].attach(VLARecord, rca.ADAOffset(a));
        cout << "Antenna " << adaBlock[a].antName() 
         << " is on pad " << adaBlock[a].padName() << endl;
      }

Motivation

This class was needed as part of the VLA filler application.

Thrown Exceptions

compiled in debug mode this class does a lot of consistancy checking. If it detects anomolies it will throw an exception (AipsError).

To Do

• The member functions should probably be rounded out.

Definition at line 106 of file VLAADA.h.

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Constructor & Destructor Documentation

VLAADA::VLAADA

(

)

The default constructor creates a unusable object.

You need to use the assignment operator or the attach function to create a usable object.

VLAADA::VLAADA	(	ByteSource &	record,
		uInt	offset
	)

Construct this object to read data from the specified VLA logical record.

The antenna data area that will be used begins at the specified number of bytes from the beginning of the record.

VLAADA::~VLAADA

(

)

The destructor is trivial.

VLAADA::VLAADA

(

const VLAADA &

other

)

The copy constructor uses reference semantics.

---

Member Function Documentation

uInt VLAADA::antId

(

)

const

returns the antenna Id.

This is a number which stays with the "steel" and gets moved to new locations. It is not the pad number. It is between 1 and 28 inclusive.

String VLAADA::antName

(

Bool

newStyle = True

)

const

return the antenna name.

This is a string version of the antenna id n is a one or two digit number that contains the antenna identifier (see below).

String VLAADA::arrayName

(

)

const

Identifies which array an antennn belongs to: VLA, EVLA, or VLBA.

void VLAADA::attach	(	ByteSource &	record,
		uInt	offset
	)

Re-initialise this object so that it now reads data from the given VLA logical record.

The antenna data area that will be used begins at the specified number of bytes from the beginning of the record.

Double VLAADA::bx

(

)

const

return the Bx position in meters of this antenna, from the centre of the Array.

Double VLAADA::by

(

)

const

return the By position in meters of this antenna, from the centre of the Array.

Double VLAADA::bz

(

)

const

return the Bz position in meters of this antenna, from the centre of the Array.

Float VLAADA::frontEndTemp

(

VLAEnum::IF

which

)

const

Front end Temp...gives a clue if antenna is EVLA.

Stokes::StokesTypes VLAADA::ifPol

(

VLAEnum::IF

which

)

const

return the IF polarisation.

Normally at the VLA IF's A & B measure right-hand-circular polarisation, and IF's C & D measure left-hand-circular polarisation. But in special circumstances this can be swapped. This function returns Stokes::RCircular or Stokes::LCircular.

uInt VLAADA::ifStatus

(

VLAEnum::IF

which

)

const

return the IF status.

The status indicates how bad the data probably is for the specified if and the current antenna. Values of zero indicate the IF is OK, 1 is a warning, 2 means not so good, and bigger numbers, up to 15 mean the IF is successively worse.

Float VLAADA::nominalSensitivity

(

VLAEnum::IF

which

)

const

returns the nominal sensitivity of the specified IF.

These numbers are multiplied by the raw correlaton co-efficients to produce the numbers in the correlation data area.

Bool VLAADA::nomSensApplied	(	VLAEnum::IF	which,
		const uInt	rev
	)		const

Has the nominal sensitivity amplitude scaling been applied? (auto-True prior to revision 25 [exclusive])

Bool VLAADA::ok

(

)

const

Function which checks the internal data of this class for consistant values.

Returns True if everything is fine otherwise returns False.

VLAADA& VLAADA::operator=

(

const VLAADA &

other

)

The assignment constructor uses reference semantics.

String VLAADA::padName

(

)

const

return the pad name that this antenna is currently located on.

This is obtained by knowing where the pads are and looking at the bx position of the antenna (the bx position in the logical record has to be within half a meter of the value given in an table). Pad names are of the form "Nn" or "En" or "Wn" where n is a one or two digit number that has an approximate correspondence with the distance of the pad from the centre of the array.

Vector<Double> VLAADA::pos

(

)

const

return the bx, by, bz positions in meters of this antenna, from the centre of the Array.

Double VLAADA::u

(

)

const

return the u coordinate in meters of this antenna at the centre of the integration.

Double VLAADA::v

(

)

const

return the v coordinate in meters of this antenna at the centre of the integration.

Double VLAADA::w

(

)

const

return the w coordinate in meters of this antenna at the centre of the integration.

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Member Data Documentation

uInt VLAADA::itsOffset [private]

Definition at line 212 of file VLAADA.h.

ByteSource VLAADA::itsRecord [mutable, private]

Definition at line 209 of file VLAADA.h.

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

• code/nrao/VLA/VLAADA.h