AIPS HELP file for RFLAG in 31DEC24
As of Thu Apr 18 14:47:05 2024
RFLAG: Flags data sets based on the rms in visibilities
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 #
SOURCES Source name
QUAL -10.0 Calibrator qualifier -1=>all
CALCODE Calibrator code ' '=>all
TIMERANG Time range to use
SELBAND Bandwidth to select (kHz)
SELFREQ Frequency to select (MHz)
FREQID Freq. ID to select.
SUBARRAY 0.0 1000.0 Sub-array, 0=>all
DOCALIB -1.0 101.0 > 0 calibrate data & weights
> 99 do NOT calibrate weights
GAINUSE CL (or SN) table to apply
DOPOL -1.0 10.0 If >0.5 correct polarization.
PDVER PD table to apply (DOPOL>0)
BLVER BL table to apply.
FLAGVER Flag table version
DOBAND -1.0 10.0 If >0.5 apply bandpass cal.
Method used depends on value
of DOBAND (see HELP file).
BPVER Bandpass table version
SMOOTH Spectral smoothing function
Dangerous here - see help.
OUTFGVER 0.0 Output flag table: 0 new
STOKES Stokes type ' ' => 'RLLR'
UVRANGE Restrict baselines in klambda
BIF Begin IF to process this time
EIF End IF to process this time
YINC Number of time samples
averaged before algorithms
DCHANSEL Array of start and stop chan
numbers, plus a channel
increment and IF omitted from
all operations.
ICHANSEL Array of start and stop chan
numbers, plus a channel
increment and IF to be used
to select channels to sum to
find spectral rms.
AVGCHAN 0.0 16384.0 Width of median window in
the spectral flagging mode
DOSCALE -1.0 1.0 > 0 -> determine relative
gains first
DOPLOT -16.0 16.0 > 0 -> plot, else flag data
(see help)
< 0 -> flag data, plot after
DOFLAG > 0 -> flag when DOPLOT > 0
FPARM (1) > 0 rolling T buffer to
find time rms F(1) times
(2) Normal time interval
between samples (sec)
IMPORTANT TO BE ~RIGHT
and before time averaging
with YINC
(3) Maximum rms allowed in
Jy in time rms
(4) if not 0, do robust rms
spectrally and flag
channels deviating > F(4)
(5) NEW - see HELP
# channels taken from
each spectral window
(6) NEW - see HELP
expand flagged region
(7) flag whole spectrum if
fraction flagged > F(7)
(8) flag F(8) channels
between flag groups
(9) scale mean rms to compute
NOISE, 0 -> 5.
(10) scale mean deviation to
compute SCUTOFF. 0 -> 5
(11) Flag all baselines if
a channel > F(11) flagged
(12) Flag all baselines to an
antenna if a channel >
F(12) flagged
(13) Flag any visibility amp
> F(13) before time rms
0 -> 1.E6 IMPORTANT
(14) Flag times with fewer
than F(14) baselines
(15) Flag baseline if any vis
> FPARM(15)
(16) Flag both ants if any
vis > FPARM(16)
(17) Flag a channel if >F(17)
of the times are flagged
(18) > 0 -> use a table to
hold baseline based values
of NOISE and SCUTOF
(20) >= 1 => flag only center
time in bin
VPARM (1) Time rms upper limit to
histogram (Jy) 0 -> 2
(2) Spectral rms upper limit
to histogram (Jy)
(3) Plot only lower V(3)
portion of plots 0 -> 1
(4,5) Min/max time box to be
plotted
(6) Max Y time histogram
(7) Max Y time cumulative
(8,9) Min/max spectral box
to be plotted
(10) Max Y of spectral plot
(11) Max Y cumulative spect.
(12,13) min/max of average
rms versus channel plot
(14,15) min/max of average
deviation vs channel plot
NOISE $ If FPARM(3) < 0, NOISE(i) is
the max allowed in time rms
for IF i (Jy)
Returned when DOPLOT not 0
SCUTOFF $ If FPARM(4) < 0, SCUTOFF(i)
is max allowed deviation in
a channel for IF i (Jy)
Returned when DOPLOT not 0
DOOUTPUT -1.0 1.0 > 0 => write new data set
applying new flags
OUTNAME Output data set name
OUTCLASS Output data set class
OUTSEQ 0.0 Output data set seq #
OUTDISK Output data set disk #
DOTV -1.0 1.0 > 0 Do plot on the TV, else
make a plot file
GRCHAN 0.0 7.0 Graphics channel 0 => several
LTYPE -410.0 410.0 Type of labeling: 1 border,
2 no ticks, 3 standard, 4 rel
to center, 5 rel to subim cen
6 pixels, 7-10 as 3-6 with
only tick labels
<0 -> no date/time
FUNCTYPE 'LG' plot log of counts
else plot is fully linear
XYRATIO 0.0 X/Y ratio 0 -> fit TV or
1.414 PLot files
NBOXES 0.0 20000.0 Number histogram boxes
DOWEIGHT -1.0 3.0 > 0, write OUTTEXT w weights
OUTTEXT Text file of channel weights
BADDISK Disks to avoid for scratch
HELP SECTION
RFLAG
Task: This task examines SELECTED visibility spectra looking for RFI
primarily. It examines the rms versus time over short time
intervals a polarization and a spectral channel at a time.
Those exceeding user-specified threshold(s) are flagged in
all polarizations.
The task can pre-average over time (YINC intervals) on the fly
before carrying out all algorithms. Frequency averaging is
accomplished with the SMOOTH adverb. The task assumes that the
times in the data set are approximately the same for all
baselines. Data sets produced by UBAVG (or procedure STUFFR)
have averaged the data by different amounts depending on
baseline length. Even UVAVG can result in samples at quite
different times for each baseline; OPCODE 'TIME' or 'GRID'
should be used in UVAVG if the data are then to be given to
RFLAG.
The pre-clip option (FPARM(13)) should be used to eliminate
really bad values before the statistics are computed. If you
do not, then RFLAG has been known to return infinities and NaNs
(not a number).
Optionally, the robust average and rms of the real and
imaginary parts of the visibility at each time are found in
each IF individually. Those channels deviating from this
average by more than a user-specified cutoff in Jy are also
flagged in all polarizations.
To aid in setting the cutoff values, RFLAG can begin by
computing histograms of the time rms and of the spectral
deviations. It can also compute means and rmses of the time
rms and of the deviations from the spectral fits as a function
of spectral channel and IF. The computations done for the
returned adverb values (NOISE, SCUTOFF) which may be used for
the actual flagging. The histograms, cumulative histograms,
and spectral functions may be plotted. Following the plots,
the program can go on to flag the data immediately or it can
leave that operation for a later execution.
Note that the cutoffs are all in Jy. That may make particular
values suitable only for sources within a modest range of
fluxes. RFLAG may then need to be used multiple times, once
for strong calibrators, once for modest calibrators, and one
more time for weak target sources.
It may be better to use, e.g. 'RLLR' Stokes or 'QU' for this
purpose than I which is likely to have larger signals perhaps
made "noisier" by delay rocking and other gain-like errors.
Stokes V may suffer from errors in calibration causing spurious
values way larger than the true V polarization (if any). Note
one gotcha: if one of RR and LL is known to be bad, it has been
traditional to flag it and both cross hands. If you use only
cross-hand polarizations, times previously flagged in this
manner will not be examined. STOKES='HALF' may be needed but
with cutoff values different from when using STOKES='RLLR'.
There are a large number of "knobs" in this task, so it may be
best to suggest standard ways to use it. You may wish however
to consider many other choices. In general, the first use of
the task will be run first with DOPLOT = 12 to look at cutoff
levels and spectral plots. Then - without changing any other
adverb - setting DOPLOT = -12 to apply the clip levels found in
the first pass and then to compute a new set of clip levels.
Leave DOFLAG=0 and let DOPLOT control whether flagging is
actually done.
FPARM is the main control adverb.
FPARM(1) = 3 or 5
FPARM(2) = normal interval between samples in sec
FPARM(3) = -1 -> use NOISE(if number) to clip time rms
FPARM(4) = -1 -> use SCUTOFF(if #) to clip frequency
spikes
= 0 for spectral-line data unless the channels are
known and DCHANSEL is set appropriately
FPARM(5) = 0.001 -> evaluate each spectral channel against
its median and shift by 1 channel
FPARM(6) = 1 -> flag one adjacent channel on each side of
flagged channels
FPARM(7) = 0.85 -> if >= 85 percent of a channel is flagged, flag
all of that channel
FPARM(8) = 2 -> if there are <= 2 channels between flagged
channels, flag them also
FPARM(9) = 7 -> set clip levels at 7 * "rms" for NOISE
FPARM(10) = 7 -> set clip levels at 7 * "rms" for SCUTOFF
FPARM(11) = 0.75 -> if a channel is flagged in >= 75 percent of
baselines at a time, flag all baselines
for that channel
FPARM(12) = 0.75 -> if a channel is flagged in >= 75 percent of
baselines to an antenna at a time, flag
that antenna for that channel
FPARM(13) = 50 -> flag all data samples > 50 Jy before
doing any of this
FPARM(14) = 20 -> flag any time/channel samples having fewer
than 20 baselines
FPARM(17) = 0.5 -> flag any channel for which more than half
of the times are flagged
Usually one starts with cross-hand data STOKES='RLLR' but one
may need to repeat with STOKES = 'HALF'. Note that these
values for FPARM(6) and FPARM(8) may be viewed as "harsh".
If doing the spectral median filter, a largish AVGCHAN such as
19 may be appropriate.
VPARM controls the plots and usually can be left all zero.
If you find that your clip levels must depend on UVRANGE, then
you must separate wide-band data into separate files for each
IF. The UVRANGE test is based on the header frequency of a
file and includes all spectral windows/channels for which the
HEADER frequency gives a suitable baseline length. (Note -
this is true throughout AIPS.)
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.
SOURCES....Source to be copied. ' '=> all; if any starts with a
'-' then all except ANY source named.
QUAL.......Qualifier of source to be copied. -1 => all.
CALCODE....Calibrator code of sources to copy. ' '=> all.
TIMERANG...Time range of the data to be copied. In order: Start day,
hour, min. sec, end day, hour, min. sec. Days relative to
ref. date.
SELBAND....Bandwidth of data to be selected. If more than one IF is
present SELBAND is the width of the first IF required.
Units = kHz. For data which contain multiple
bandwidths/frequencies the task will insist that some form
of selection be made by frequency or bandwidth.
SELFREQ....Frequency of data to be selected. If more than one IF is
present SELFREQ is the frequency of the first IF required.
Units = MHz.
FREQID.....Frequency identifier to select (you may determine which is
applicable from the OPTYPE='SCAN' listing produced by
LISTR). If either SELBAND or SELFREQ are set, their values
override that of FREQID. However, setting SELBAND and
SELFREQ may result in an ambiguity. In that case, the task
will request that you use FREQID.
SUBARRAY...Sub-array number to copy. 0=>all.
DOCALIB....If true (>0), calibrate the data using information in the
specified Cal (CL) table for multi-source or SN table for
single-source data. Also calibrate the weights unless
DOCALIB > 99 (use this for old non-physical weights).
GAINUSE....version number of the CL table to apply to multi-source
files or the SN table for single source files.
0 => highest.
DOPOL......If > 0 then correct data for instrumental polarization as
represented in the AN or PD table. This correction is
only useful if PCAL has been run or feed polarization
parameters have been otherwise obtained. See HELP DOPOL
for available correction modes: 1 is normal, 2 and 3 are
for VLBI. 1-3 use a PD table if available; 6, 7, 8 are
the same but use the AN (continuum solution) even if a PD
table is present.
PDVER......PD table to apply if PCAL was run with SPECTRAL true and
0 < DOPOL < 6. <= 0 => highest.
FLAGVER....specifies the version of the flagging table to be applied.
0 => highest numbered table.
<0 => no flagging to be applied.
Keep track of your FG table versions to be certain that
you are using all of the flags that you intend to use.
DOBAND.....If true (>0) then correct the data for the shape of the
antenna bandpasses using the BP table specified by BPVER.
The correction has five modes:
(a) if DOBAND=1 all entries for an antenna in the table
are averaged together before correcting the data.
(b) if DOBAND=2 the entry nearest in time (including
solution weights) is used to correct the data.
(c) if DOBAND=3 the table entries are interpolated in
time (using solution weights) and the data are then
corrected.
(d) if DOBAND=4 the entry nearest in time (ignoring
solution weights) is used to correct the data.
(e) if DOBAND=5 the table entries are interpolated in
time (ignoring solution weights) and the data are then
corrected.
IMAGR uses DOBAND as the nearest integer; 0.1 is therefore
"false".
BPVER......Specifies the version of the BP table to be applied
0 => highest numbered table.
<0 => no bandpass correction to be applied.
SMOOTH.....Specifies the type of spectral smoothing to be applied to
a uv database . The default is not to apply any smoothing.
NOTE: SMOOTH IS VERY DANGEROUS IN THIS CONTEXT. IF ONE
USES IT AND FLAGS SOME CHANNELS THE VALUES IN UNFLAGGED
CHANNELS CHANGE MAKING RFLAG APPEAR TO HAVE NOT FLAGGED
ALL THAT IT SHOULD HAVE. If you realy need SMOOTH to
remove ringing from narrow-band signals, run SPLAT on the
data to apply the SMOOTH and then set SMOOTH=0 for later
work. The elements of SMOOTH are as follows:
SMOOTH(1) = type of smoothing to apply: 0 => no smoothing
To smooth before applying bandpass calibration
1 => Hanning, 2 => Gaussian, 3 => Boxcar, 4 => Sinc
To smooth after applying bandpass calibration
5 => Hanning, 6 => Gaussian, 7 => Boxcar, 8 => Sinc
SMOOTH(2) = the "diameter" of the function, i.e. width
between first nulls of Hanning triangle and sinc
function, FWHM of Gaussian, width of Boxcar. Defaults
(if < 0.1) are 4, 2, 2 and 3 channels for SMOOTH(1) =
1 - 4 and 5 - 8, resp.
SMOOTH(3) = the diameter over which the convolving
function has value - in channels. Defaults: 1,3,1,4
times SMOOTH(2) used when input SMOOTH(3) < net
SMOOTH(2).
OUTFGVER...Output flag table version.
0 -> new version and the contents of FLAGVER are copied
to it initially.
n = pre-existing file -> new flags are appended to the
OUTFGVER but FLAGVER is not copied.
OUTFGVER may point to the same file as FLAGVER. In that
case, FLAGVER and any new flags are put in a temporary
flag table and finally the temporary flag table replaces
the input FLAGVER.
STOKES.....Type of Stokes parameters to examine. All Stokes will be
flagged whenever one of the examined ones is deemed out
of bounds. ' ' => 'RLLR'
UVRANGE....Restrict the examination of data to the specified range
of baseline lengths in klambda at the reference
frequency. UVRANGE(2) <= UVRANGE(1) => UVRANGE(2)=1.E12
BIF........First IF included in operation
EIF........Last IF included in operation
Plots sum the histograms over included channels and IFs
but the time rms is done one spectral channel and IF at a
time for computing the rms and for flagging and the
spectral fitting is done one IF at a time.
YINC.......Pre-average over YINC time samples before carrying out
the other algorithms. <= 0 -> 1.
DCHANSEL...Array of start, stop, and increment channel numbers plus
an IF used for channel DESELECTION. Any group of
channels specified will not be examined for time or
spectral rms and will not be flagged except when the full
spectrum is flagged. Up to 20 sets of channels/IF may be
entered. The first having DCHANSEL(2,i) <= 0 terminates
the list. DCHANSEL(4,i) is the IF number, with <= 0
meaning all. If an IF has no DCHANSEL set for it, then
all channels in the IF are included in the rms and
flagging oprations.
ICHANSEL.. Array of start, stop, and increment channel numbers plus
an IF used for channel selection in the averaging to
compute a spectral rms. Up to 20 sets if channels/IF may
be entered. The first having ICHANSEL(2,i) <= 0
terminates the list. ICHANSEL(4,i) is the IF number,
with <= 0 meaning all IFs. If an IF has no ICHANSEL set
for it, then ALL channels will be used. Note that this
is a non-standard default appropriate to the sliding
median window method now used.
For instance, if you wished to exclude channels 1 - 10
and 121 - 128 because of bandpass effects, and channels
56 - 80 of IF 1 but not IF 2 because of interference,
then you would set ICHANSEL = 11,55,1,1, 81,121,1,1,
11,121,1,2. If you only wished to use every other
channel from the second IF then you would set ICHANSEL =
11,55,1,1, 81,121,1,1, 11,121,2,2. if there are actually
4 IFs, then IFs 3 and 4 would use channels 17 through
112. To set the channel range for all IFs to 14, 115
enter ICHANSEL = 14,125. To set the channel range for
all IFs to 14-115 except IF 3 set ICHANSEL=14,115,1,0,
23 45,1,3, 64,101,1,3 where the all IF part must come
before the parts that partially override it.
AVGCHAN....The spectral mode uses a median window AVGCHAN spectral
channels wide where AVGCHAN is forced to be odd. The
default is one or two less than the full width of the
spectrum. The value at the center of the window is
compared to the median value of the window and values
more than FPARM(4) or SCUTOFF will be flagged.
DOSCALE....> 0 -> Read the data through to find separate amplitude
gains for each baseline and IF and apply those to the
data when plotting and flagging. The median amplitude of
the channels in each spectral window at each sample is
taken as the amplitude to be averaged over all times.
<= 0 -> do not determine such gains and do not apply
them.
DOPLOT.....If DOPLOT > 0, histograms of the time rms and of the
deviations from the spectral fit are computed. Also
computed are the mean time rms and the mean deviation
from the spectral fit in each spectral channel. These
are then used to set the adverbs NOISE and SCUTOFF.
If 16 > DOPLOT > 0, it is broken into a bit pattern and
plots corresponding to the bits that have value are
generated.
bit 1 (1,3,5,...) => Plot the time rms and the spectral
deviations as histograms.
bit 2 (2,3,6,...) => Plot the cummulative histograms
(fraction of data above x)
bit 3 (4,5,6,...) => Plot the spectrum of time rms
(average and deviation in each channel) versus
channel
bit 4 (8,9,10,..) => Plot the spectrm of deviation from
the spectral fit (average and rms) versus channel
= 0 => Do not do the plots and do not change the input
values of NOISE and SCUTOFF.
DOPLOT < 0 => flag the data with FPARM and possibly NOISE
and SCUTOFF. Then plot the data using the new flag table
with abs(DOPLOT) providing the plot control as above.
DOFLAG.....If DOFLAG > 0 or DOPLOT <= 0, compute the time rmses and
optionally spectral fits with deviations and generate
flag table entries for the data in excess of the cutoffs.
This means that one can
(a) compute NOISE and SCUTOFF and then use them (or use
FPARM(3) and/or FPARM(4)) (DOPLOT > 0, DOFLAG > 0);
(b) use the input NOISE and SCUTOFF (or FPARM(3) and/or
FPARM(4)) without changing them (DOPLOT <= 0, and any
DOFLAG);
(c) compute NOISE and SCUTOFF and generate plots (16 >
DOPLOT > 0 and DOFLAG <= 0) with no flagging; and
(d) compute NOISE and SCUTOFF and generate plots (DOPLOT
>= 16 and DOFLAG <= 0) with no flagging;
(e) use the input NOISE and SCUTOFF (or FPARM(3) and/or
FPARM(4)) without changing them (DOPLOT < 0 and any
DOFLAG) to flag the data follwoed by data plots generated
with the new flag table.
FPARM......(1) Number of times to be included in the time rms. We
recommend an odd number and < 3 -> 3.
(2) Normal interval between samples in seconds. The
program will not do intervals longer than 2 *
FPARM(1) * FPARM(2). 0 -> 10 secs
IT IS IMPORTANT TO HAVE THIS ABOUT RIGHT. If it is
too short, in particular, then data samples that
belong in the same bin (time interval) may end up in
different bins. This happens most often when data
have been time averaged after selective flagging.
Set it to somewhat less than the averaging time -
if observations at XINT are averaged over N times,
set FPARM(2) = (N-0.5) * XINT.
Units are seconds and before any YINC averaging.
(3) Flag all data having a time rms > FPARM(3) Jy.
0 -> 1.e6. If FPARM(3) < 0.0, use NOISE(i) as the
clip level for IF i instead of FPARM(3). If
FPARM(18) > 0, NOISE is ignored and the NS table is
used instead. If ABS(FPARM(3)) >= 1.E6, the
computation of time rms is not done under any
circumstances, so no time rms flags, plots, and
changed output NOISE values occur.
(4) If FPARM(4) not 0, also do a median-window operation
over the spectral channels in each IF. Flag those
channels which differ from the median by more than
FPARM(4) Jy when FPARM(4)>0. If FPARM(4)<0, do this
flagging using IF-dependent values SCUTOFF(i) instead
of FPARM(4). If FPARM(18) > 0, SCUTOF is ignored and
the NS table is used instead. The computation is
done separately for the real and imaginary parts.
The width of the window is set by AVGCHAN. 0 -> do
not do the spectral computation.
(5) The center channel plus FPARM(5) channels on each
side of the central channel are evaluated from each
spectral median-filter window. That window then
moves 1+2*FPARM(5) for the next evaluation - speeding
the spectral analysis process. 0 -> AVGCHAN/40,
-1 -> 0. If AVGCHAN is say 101, then the default
would take 5 channels at a time centered in each
window and the next window would start 5 channels
later than the previous one.
(6) After the time and spectral flagging is evaluated for
each time, expand each region of flagged channels by
FPARM(6) channels in each direction. This occurs
before the application of the options in FPARM(7),
FPARM(8), FPARM(11), and FPARM(12).
(7) If the fraction of channels to be flagged (and
previously flagged) in a given time and IF sample
exceeds FPARM(7), flag the whole thing. Note that
this looks at the results of the time rms and the
spectral rms (if any) plus the FPARM(8) test. It is
done both before and after the FPARM(10) test. 0->1
(8) Flag up to FPARM(8) "good" channels located between
groups of flagged channels. Thus if we are to flag,
for example, channels 12-14, 16-20, 23-24, and 28-30
and FPARM(7)=2, then we will flag 12-24 and 28-30.
(9) When DOPLOT > 0, the program sums the time rmses in
each channel separately. It then computes the mean
and rms of these time rmses in each channel and finds
the median average channel rms over each IF and its
variance. Adverb NOISE(i) is set to FPARM(9) *
(median + variance). 0 -> 5.0 which seems to be a
good value.
(10) When DOPLOT > 0, the program sums the deviations
from the spectral fit (if FPARM(4) not 0.0) in each
channel separately. It then computes the mean rms
of these deviations in each channel and finds the
median average channel deviation over each IF and its
variance. Adverb SCUTOFF(i) is set to FPARM(10) *
(median + variance). 0 -> 5.0 which may be a good
value.
(11) If a channel is flagged at one time in > FPARM(11)
fraction of the baselines, flag it in all baselines
at that time. 0 -> 1 => don't do this.
Note that autocorrelations are allowed, so the
maximum number of "baselines" is (Mant * (Mant+1)) /
2 where Mant is the maximum antenna number. Thus the
EVLA with Mant = 28 has 406 "baselines" rather than
351 when antenna 28 is in the array.
(12) If a channel is flagged at one time in > FPARM(12)
fraction of the baselines to a particular antenna,
flag it in all baselines to that antenna at that
time. 0 -> 1 => don't do this.
Note that autocorrelations are allowed, so the
maximum number of "baselines" to an antenna is the
maximum antenna number.
(13) Examine the data before doing any other checks and
flag all samples > FPARM(13) Jy. 0 -> 1.E8.
(14) Examine the data before doing any other checks and
flag all baselines when there are fewer than
FPARM(14) baselines with valid data, channel by
channel, IF by IF. This is called a quack operation
but applies at any time, not just the start and end
of scans.
(15) Examine the data before doing other checks and, if
any channel has amplitude > FPARM(15), flag all
channels in that baseline and IF.
(16) Examine the data before doing any other checks and,
if any channel has amplitude > FPARM(16), flag all
channels in that IF for every baseline involving the
two antennas of the subject baseline.
(17) 0 < FPARM(7) < 1 says to flag any channel for which
the fraction of times flagged is > FPARM(17).
(18) If > 0, make an NS extension table containing NOISE
and SCUTOF with values for each baseline separately
when computing NOISE and SCUTOF. The plots combining
all baselines are still done and the combined NOISE
and SCUTOF are still returned. If flagging data, use
the highest version of NS table to set the cutoff
levels as a function of both IF and baseline.
If <= 0, combine all baselines and ignore any NS
tables.
(20) >= 1.0 => flag only the center time in a time bin
when the time rms is excessive. This is not
recommended when actually doing time rms flagging.
If FPARM(3) is very large so that only spectral
flagging is actually being done, this option may
speed the performance to the spectral code.
VPARM......Plot controls when DOPLOT > 0:
(1) Highest rms to histogram in the time-based rms's.
0 -> 2 Jy.
(2) Highest deviation to histogram in the spectral
histogram. 0 -> 2 Jy
(3) Plot only the lowest FPARM(10) portion of each plot
< 0.001 -> 1.0 Since you are usually interested only
in the lower portions, this option is quite useful.
(4) Minimum time rms histogram box to plot
(5) Maximum time rms histogram box to plot
If 0 < VPARM(4) < VPARM(5), the specified range of
boxes will be plotted. Otherwise, the lowest box > 0
to the highest box > 0 is the range plotted.
(6) > 0 -> Maximum value on Y axis for time rms
histogram before VPARM(3).
(7) > 0 -> Maximum value on Y axis for time rms
cumulative histogram before VPARM(3).
(8) Minimum spectral deviation histogram box to plot
(9) Maximum spectral deviation histogram box to plot
If 0 < VPARM(8) < VPARM(9), the specified range of
boxes will be plotted. Otherwise, the lowest box > 0
to the highest box > 0 is the range plotted.
(10) Maximum value on Y axis of spectral deviation
normal histogram before VPARM(3).
(11) > 0 -> Maximum value on Y axis for spectral
deviation cumulative histogram before VPARM(3).
(12,13) Min and max of plot of mean time rms as a
function of channel.
(14,15) Min and max of plot of mean spectral deviation as
a function of channel.
NOISE......DOPLOT <= 0 : If FPARM(3) < 0, NOISE(i) will be used as
the maximum allowed time rms for IF i. Units are Jy.
DOPLOT > 0 : Value of median time rms plus median rms of
rmses times FPARM(9) in each IF. NOISE is a returned
adverb value not an input and is plotted as a straight
line in each IF when bit 3 of DOPLOT is on
(=4,5,6,..). NOISE may then be applied (if FPARM(3) <
0) in the same execution of RFLAG if DOFLAG > 0.
SCUTOFF....DOPLOT <= 0 : If FPARM(4) < 0, SCUTOFF(i) will be used as
the maximum allowed deviation from the spectral fit
for IF i. Units are Jy.
DOPLOT > 0 : Value of median spectral deviation plus
median rms of devaitions times FPARM(10) in each IF.
SCUTOFF is a returned adverb value not an input and is
plotted as a straight line in each IF when bit 4 of
DOPLOT is on (=8,9,10,..). SCUTOFF may then be
applied in the same eecution of RFLAG to generate
flags (if FPARM(4) < 0) if DOFLAG > 0.
DOOUTPUT...> 0 => write an output data set with the latest flags
applied, if new flags were found.
OUTNAME....Output UV file name. ' ' => INNAME
OUTCLASS...Output UV file class. ' ' => RFLAG
OUTSEQ.....Output UV file sequence number. 0 => highest
OUTDISK....Output UV file disk. 0 -> highest with room
DOTV.......> 0 => plot directly on the TV device, otherwise make a
plot file for later display on one or more devices
(including the TV if desired).
GRCHAN......Graphics channel (1 - 7) to use for line drawing.
0 => use multiple graphics planes for the various parts
of the graphical drawing.
LTYPE.......Labelling type, see HELP LTYPE for details:
1 = border, 2 = no ticks, 3 or 7 = standard, 4 or 8 =
relative to ref. pixel, 5 or 9 = relative to subimage
(BLC, TRC) center, 6 or 10 = pixels. 7-10 all labels
other than tick numbers and axis type are omitted.
Less than 0 is the same except that the plot file
version number and create time are omitted.
Add n * 100 to alter the metric scaling.
FUNCTYPE....Histogram transfer function: 'LG' => log else linear.
X axis (rms in Jy and deviation in Jy) is linear.
XYRATIO.....Scale the X axis longer than the Y by XYRATIO.
If DOTV > 0, 0 -> fit to the TV window
If DOTV <= 0, 0 -> 1.414.
NBOXES......Number of cells for histogram. 20 <= nboxes <= 20000
< 20 -> 200.
DOWEIGHT....If OUTTEXT is not blank and DOWEIGHT > 0, write a text
file with channel dependent weights. Note that
DOPLOT must not be zero for this to be meaningful.
DOOUT = 1 => use time rmses only
DOOUT = 2 => use freq rmses only
DOUUT = 3 or more => use both.
OUTTEXT.....See DOWEIGHT above, gives path to desired text file.
BADDISK.....The disk numbers to avoid for scratch files.
EXPLAIN SECTION