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Basic Information on smafix
Task: smafix
Purpose: Plot and fit Tsys and do Tsys corrections.
Categories: plotting, analysis and uvdata correction
SmaFix plots and does least square fitting with an order
of polynomial to the antenna-based Tsys measurements.
SmaFix also applies the Tsys corrections to the visibilies.
SmaFix can handle upto 100 sources per file. For options
of polynomial fitting to the data of individual sources
separately, the maximum number sources that can be handled
in SmaFix is 48.
Key: vis
The name of the input data-set. No default.
Key: out
The name of the output data-set with corrections. No default.
Key: device
The PGPLOT plotting device to use. The default is no plot.
Key: log
The log to give a listing of the variables. The default is no log.
Key: xaxis
Variable to plot on the X axis. Currently supports
"time" and antel". Default is "time".
Key: yaxis
Variable to plot on the Y axis. Default is "systemp".
Currently supports only "systemp".
Key: nxy
Number of plots in the x and y directions. The default varies.
Key: bant
An array of antenna ids of which the antennas
are corrupted in Tsys measurements.
example: bant=4, 8 indicates that the Tsys values of both
the antennas 4 and 8 are corrupted.
Key: fscal
An array of scaling factors to scale the Tsys values from
the good antenna (gant) to those of bad antennas (bant):
Tsys_bant(i) = fscal(i) * Tsys_gant.
Default is unity.
Key: gant
A antenna id with good Tsys measurements which will
be used to replace the Tsys of the antennas assigend
with bant.
example: gant=1 assigns antenna 1 with good Tsys
to replace the Tsys values of antennas 4 and 8.
Defaults are no replacements.
Key: xrange
The min and max range along the x axis of the plots. The default
is to autoscale. Note that for "time" should be given in normal Miriad
time format (either absolute time or time-of-day).
Key: yrange
The min and max range along the y axis of the plots. The default
is to autoscale. Note that for "time" should be given in normal Miriad
time format (either absolute time or time-of-day).
Key: dofit
A degree polynomial fit. Value 2 is for parabolic, 3 for cubic.
Default or a value of 0 and smaller corresponds to no fit to perform.
Key: options
Extra processing options. Several can be given, separated by
commas. Minimum match is used.
"dtime" If the x-axis is "time", plot the time in fractions
of a day. The default is to plot in hh:mm:ss.
"compress" If the variable is a 2D array of values, average
the variables along the second dimension.
"overlay" By default, when a variable takes on several values,
each is plotted on a separate plot. The overlay
option makes a single plot.
"unwrap" Unwrap the phases on the yaxis variable. Cannot unwrap
an xaxis variable. By default phases are not unwrapped.
"tsyscorr" If the y-axis is "systmp", Tsys correction will be
applied.
By default, no Tsys corrections are made.
"dosour" If dofit is true, then the polynomial fit is source
dependent.
By default, no source separation is made.
"tsysswap" Swaps the values of systemp with a polynomial fit
in the Tsys corrections, saves the values from
the polynomial fit to replace the original
systemp and creates a new variable systmp to
save the original Tsys measurements.
For the cases of options=tsysfix or dofit > 0, gant > 0,
tsysswap is the defualt.
"all" uses all data associated with flagged and unflagged
visibilties. The default uses only unflagged
(good) data.
"tsysfix" uses the polynomial fit to Tsys from the unflagged (good)
data to interpolate the Tsys at flagged data points
and replaces only the bad Tsys values with the polynomial
fit in the case of the Keyword dofit = 1 or greater.
The flag state will be reset to 'unflag' for all the
visibilities except for those with illegal polarization
states. Warning: this options will also reset the flag
states passed from the SMA online system.
By default (both tsysswap and tsysfix are not chosen
in options), the original Tsys measurements will
be used in the Tsys corrections and the variables
from the input uvdata file remains unchanged if
options=tsyscorr is chosen.
"2GHz" uses 2GHz Tsys correction scheme for 4GHz data.