sd.selector

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5.1.3 sd.selector - Tool

Data selection tool for single-dish data
Description

The selector is a data selection object that affects a scantable object via set_selection function. Selection by the following attributes are available:

scan number
beam number
cycle number
IF number
source name (allows regular expression)
polarization number
row number
source type
value of system temperature (minimum and maximum threshold)

Note that the selection by an integer is 0-based (scan, beam, cycle, IF, polarization, and row).

In addition, the selector provides interface for more flexible data selection using TaQL.

The selector also support sorting data. The selector sorts data based on values of columns specified by the user.

Summary of the current selection is stored in the object as a string. Thus, you can see that summary by using print (see example below).

The constructor takes some arguments to set selection criteria. So, the user can set selection either using constructor options and available setter functions.

Source types should be given as an integer or an enumerations that are properly defined for source type. That enumeration can be accessed via sd.srctype. The list of enumerations defined (following sd.srctype.) are as follows:

enum	int	description

pson	0	on-source scan of position switched data
psoff	1	off-source scan of position switched data
nod	2	nod scan
fson	3	on-source scan of frequency switched data
fsoff	4	reference scan of frequency switched data
sky	6	sky scan for calibration
hot	7	hot load scan for calibration
warm	8	warm load scan for calibration
cold	9	cold load scan for calibration
poncal	10	on-source calibration scan of position switched data
poffcal	11	off-source calibration scan of position switched data
nodcal	12	nod calibration scan
foncal	13	on-source calibration scan of frequency switched data
foffcal	14	reference calibration scan of frequency switched data
fslo	20	lower frequency throw of symmetric freuqnecy switching
flooff	21	off-source lower frequency throw of symmetric frequency switching
flosky	26	sky lower frequency throw of symmetric frequency switching
flohot	27	hot load lower frequency throw of symmetric frequency switching
flowarm	28	warm load lower frequency throw of symmetric frequency switching

flocold	29	cold load lower frequency throw of symmetric frequency switching
fshi	30	higher frequency throw of symmetric freuqnecy switching
fhioff	31	off-source higher frequency throw of symmetric frequency switching
fhisky	36	sky higher frequency throw of symmetric frequency switching
fhihot	37	hot load higher frequency throw of symmetric frequency switching
fhiwarm	38	warm load higher frequency throw of symmetric frequency switching
fhicold	39	cold load higher frequency throw of symmetric frequency switching
sig	90	signal scan
ref	91	reference scan
cal	92	calibration scan
notype	99	no type

Arguments


Inputs
beams	Beam number selection
	allowed:	integer, integer array
	Default:	None (no selection)
cycles	Cycle number selection
	allowed:	integer, integer array
	Default:	None (no selection)
ifs	IF number selection
	allowed:	integer, integer array
	Default:	None (no selection)
name	Source name selection. Allows regular expression.
	allowed:	string
	Default:	None (no selection)
pols	Polarization number selection
	allowed:	integer, integer array, string, string array
	Default:	None (no selection)
query	TaQL selection query
	allowed:	string
	Default:	None (no selection)
scans	Scan number selection
	allowed:	integer, integer array
	Default:	None (no selection)
types	Source type selection
	allowed:	integer, integer array
	Default:	None (no selection)
rows	Row number selection
	allowed:	integer, integer array
	Default:	None (no selection)

Example

     # create a selector object
     sel=sd.selector()
     # These are equivalent if data is ’linear’
     sel.set_polarisations(["XX","Re(XY)"])
     sel.set_polarisations([0,2])
     # reset the polarisation selection
     sel.set_polarisations()
     # these are equivalent
     sel2=sd.selector(ifs=[0,1])
     sel2=sd.selector()
     sel2.set_ifs([0,1])
     # check current selection
     print sel
     IFNO: [0,1]
     # apply selection on scantable
     s=sd.scantable(’OrionS_rawACSmod_cal’,average=False)
     s.set_selection(sel)

Methods

get_beams	Return a list of current beam selection
get_cycles	Return a list of current cycle selection
get_ifs	Return a list of current IF selection
get_name	Return a selection string for source name (not yet implemented)
get_order	Return a list of columns used for sorting
get_pols	Return a list of current polarization selection
get_poltypes	Return a list of polarization types for current polarization selection
get_query	Return current selection string for TaQL selection
get_rows	Return a list of current row number selection
get_scans	Return a list of current scan number selection
get_types	Return a list of current source type selection
is_empty	Check if any selection has been set
reset	Unset all selections
set_beams	Set a sequence of beam numbers
set_cycles	Set a sequence of cycle numbers
set_ifs	Set a sequence of IF numbers
set_name	Set a selection based on a source name
set_order	Set column names that is used for sorting data
set_polarisations	Set a sequence of polarization numbers or strings
set_polarizations	Set a sequence of polarization numbers or strings

set_pols	Set a sequence of polarization numbers or strings
set_query	Set a selection string based on TaQL
set_rows	Set a sequence of row numbers
set_scans	Set a sequence of scan numbers
set_tsys	Set range of system temperature
set_types	Set a sequence of source types

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