AIPS HELP file for USUBA in 31DEC24
As of Fri Apr 19 10:07:20 2024
USUBA: Task to assign subarrays within a uv-data file
INPUTS
INNAME Input UV file name (name)
INCLASS Input UV file name (class)
INSEQ 0.0 9999.0 Input UV file name (seq. #)
INDISK 0.0 9.0 Input UV file disk unit #
OPCODE Opcode:
Automated identification:
'SCAN': print only.
'AUTO': modify data.
else, use INFILE or input
adverbs to define subarrays
Subarray selection:
TIMERANG Time range to use. 0=>all
ANTENNAS 0.0 50.0 Antenna numbers 0=>all
SOURCES Source list
FREQID Frequency id.
SUBARRAY 0.0 1000.0 Subarray, 0=>next
INFILE External text file; subarray
selection adverbs ignored in
this case.
HELP SECTION
USUBA
Task: This task allows the user to assign multiple subarrays
within a uv-data file. Both the uv-data records and
the associated tables are updated to reflect the new
subarray assignments. A single subarray can be assigned
using the input adverbs. Alternatively, multiple subarray
selections can be specified in an external text file. A
third option will automatically assign subarray numbers
after finding all instances of subarraying in the
uv-data file. This task does not modify times or antenna
numbers. Certain homogeneity tests are applied to
existing subarrays before the task will run.
Adverbs:
INNAME.....Input UV file name (name). Standard defaults.
INCLASS....Input UV file name (class). Standard defaults.
INSEQ......Input UV file name (seq. #). 0 => highest.
INDISK.....Disk drive # of input UV file. 0 => any.
OPCODE.....Subarray assignment method:
Automated subarray identification and assignment:
'SCAN' : print only; no subarrays updated.
'AUTO' : subarray labelling updated in the data.
else, use the input adverbs or the external text
file to define the subarray selection. Note: the
subarray selection adverbs are used only if
INFILE is not set and neither OPCODE='SCAN' nor
OPCODE='AUTO' is used.
TIMERANG...Time range of the specified subarray. In order:
Start day, hour, min. sec,
end day, hour, min. sec. Days relative to ref.
date.
ANTENNAS...The antenna numbers to be moved to the new
subarray. All zeroes => all antennas.
SOURCES....Source list. If the data is a multi-source file
USUBA will move the specified source(s) to the
new subarray subject to the constraints of antenna
number and time range. If SOURCE = ' ' then only
the time range and antenna list are used.
If the data is a single source file no source name
need be specified.
FREQID.....The frequency id. of the data to be moved to the
new subarray. Less than zero => ignore freq. id.
SUBARRAY...The specified data will be moved to this subarray.
0 => the next higher subarray; ex., if 5 currently
exist, a sixth will be created.
INFILE.....Name of an external text file containing a list
of subarray selection records. Type EXPLAIN USUBA
for details concerning the required format. If
INFILE is specified then the input adverbs defining
subarray selection are not used.
EXPLAIN SECTION
USUBA: Task to assign subarrays within a uv-data file
Documentor: A. J. Kemball
Related programs: FITLD, INDXR, LISTR
PURPOSE
USUBA can be used to assign multiple subarrays within a uv-data
file. The subarrays are defined through either the input adverbs, an
external text file or by utilising an option to re-number all
subarrays automatically. USUBA can be used for any interferometer
dataset but may be specifically required for VLBA data correlated with
subarrays. Subarrays are not necessarily identified correctly by FITLD
at present for such datasets.
OVERVIEW
USUBA can operate in three distinct modes:
OPCODE = 'AUTO'
In this case the subarrays are identified and labelled automatically.
An algorithm is used which minimizes the overall number of subarrays
and maximizes continuity in subarray properties. For OPCODE='SCAN',
the results of automatic subarray identification are printed but the
data are not changed.
OPCODE = ' ' and INFILE = external file
If an external text file is specified it is expected to contain a
sequence of subarray selection records in the format given below. This
option is useful, and recommended, if the subarray properties of the
dataset are simple and well-known.
OPCODE = ' ' and INFILE = ' '
In this case one subarray assignment is performed, as defined by the
subarray selection input adverbs. The resulting subarray number is
specified by adverb SUBARRAY.
FORMAT OF EXTERNAL TEXT FILE
The external text file, referenced through adverb INFILE, recognizes
the following KEYIN keywords:
ANTENNAS => array of antenna numbers
SOURCES => array of source names
TIMERANG => start day, hour, min, sec, end day, hour, min, sec.
(relative to reference date in uv-data file)
FREQID => frequency id.
SUBARRAY => desired subarray number; (default: next highest
subarray).
The file is expected to contain one or more KEYIN records, separated
by the KEYIN marker '/', each of which define a subarray selection
condition. All of the keywords are optional within any given record.
If a specific keyword is absent, that condition is not applied in
determining a subarray match. The selection conditions are not
checked for internal consistency; the last correct match is used
in defining the new subarray identifications.
Example:
! Subarray selection condition 1
ANTENNAS = 1, 3, 4, 5
SOURCES = '3C273', '1611+343'
FREQID = 1
SUBARRAY = 3 /
! Subarray selection condition 2
ANTENNAS = 6, 7, 8, 9
SUBARRAY = 4 /