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Some Useful Routines for On-Line Data Analysis
In this section we describe some useful routines for quick-look
on-line analysis of your data. For a complete description of the
routines, and for a description
of analyzing HI spectra, look at the Spectral Line Appendices.
If you want to delve into the mysteries of Analyz, you can obtain
a copy of the Analyz manual either through your Friend at the Telescope,
or through an anonymous ftp on ftp2.naic.edu (cd pub/Analyz/Analyzguide).
Real Time Data Display:
You can now use IDL to display your data as it comes from the telescope.
This is done via the following commands (note that IDL is not case-sensitive):
% gousr
% cd a9999 [or whatever your project number is
% idl
IDL
@corinit
IDL
openr,lun,'/share/olcor/corfile',/get_lun
IDL
cormon,lun
To stop the online display, just hit control-C in the IDL window.
If you wish to change the horizontal or vertical axis, just
type ver,low,high or hor,low,high . Other Arecibo-relevant IDL commands
can be found online at http://www.naic.edu/
phil/cordoc.html.
Setting Up Analyz:
Attaching Data:
(NOTE: Only one data file can be attached at a time. If you wish to compare two data sets,
save the results you wish to compare into a register(s) and then attach the new data file.
Looking at Data:
- corget
scanNo.group
= Displays the requested data dump, or the next
sequential dump if no argument
is given. That is, if you want to look at the second data dump of scan number 57401, you
`just' type ``corget 57401.00002". If you then want to look at the next (third) data dump,
you just have to type ``corget"
- correw = ``Rewinds'' data to beginning of the data file. This is necessary if you want to
use corget to look at a scan taken earlier than the one you are currently
viewing. If you get an error telling you that a scan number you are sure you've typed correctly
does not exist, most likely this is because you first need to type ``correw". The more advanced
Analyz routines do this for you automatically.
- corpl (corpla, corplb) = Plots the most recent A & B (or only A or B) data dumps
using whatever setting you've
given fcidisp. So if you have fcidisp set to 1 (just type ``corinfo" to find out the current setting),
and you just ran ``corget 57401.00002", typing corpla will plot just the polarization A parts
of scan 57401, data dump number 2, against frequency.
- pairpl
sbc
(pairpla, pairplb) = Plots the most recent (ON
OFF)/OFF spectrum against frequency (where the
data set was obtained using a dosrc, doit, domany, or median routine). If a
sub-correlator number is given (1-4), only that
sub-correlator is plotted. If pairpla or pairplb is chosen, only that polarization is plotted.
That is, typing ``pairpla 2" will plot the A polarization data from correlator board 2. ``pairpl"
will plot both the polarizations from all the boards.
- doit
scan
rec
= Calculate a single ON/OFF - 1 pair, as defined by the scan number
and total number of records, and then plot the results. This routine first averages the individual
ON and OFF records, and then calculates (ON/OFF - 1).
Data is left in the following registers:
20 - addition of all A polarization data, ON source
21 - addition of all B polarization data, ON source
22 - addition of all A polarization data, OFF source
23 - addition of all B polarization data, OFF source
24 - (ON
OFF)/OFF for polarization A
25 - (ON
OFF)/OFF for polarization B
- domany
regSrc
regCal
scan
numsets
recsSrcon
=
Processes
numsets
number of ON/OFF pairs, starting at scan number
scan
. This routine assumes a noise-diode CAL pair is taken after each ON/OFF pair.
The resultant (ON/OFF
1) spectra are stored starting in register
regSrc
for the
data pairs and starting in register
regCal
for the calibration pairs. Additionally,
the information in the last data set is left in the same registers (1 - 25) as
with the ``doit" command.
- dosrc
regSrc
scan
numsets
recsSrcon
=
Processes
numsets
number of ON/OFF pairs, starting at scan number
scan
. Unlike the domany command, this routine assumes
a noise-diode CAL pair was NOT taken after each ON/OFF pair.
The resultant (ON/OFF
1) spectra are stored starting in register
regSrc
for the
data pairs. Additionally,
the information in the last data set is left in the same registers (1 - 25) as
with the ``doit" command.
- medfonoff
regStore
scan
numrecs
=
Median filter by channel the scan pair
scan
and
scan
+1, and then
computes the ON/OFF - 1 spectrum. The data is left in the same registers as for the dosrc
command, with the difference that it is the median of all relevant sub-scan records,
not added values, that are
placed in registers 20 - 23.
medfonoff2
regStore
scan
numrecs
=
Compute individual ON/OFF - 1 by records (for
numrecs
number of
records), and then median filter the results. Uses register number
regStore
through
regStore
+2*
numrecs
+1 registers as scratch. (So be sure you have that
many registers allocated!) The results are stored in the same manner as the medfonoff
data.
Misc:
- ver
low
high
= Set low and high values for vertical display (No arguments lets Analyz choose
the values
- hor
low
high
= Set low and high values for horizontal display (No arguments lets Analyz
choose the values
- note
line no
pos
``
note
" = Places a note at the specified line. If no line number is given,
Analyz simply increments the line number. (
line no
=0 is the top of the page.) The
position, if given, is either 'L, 'C, or 'R, for left, center, or right justified. If
the position is not given, Analyz uses the last-used position. Finally, the
note can be any set of characters or numbers, and used the pgplot notation scheme.
- xcaption ``
caption
" = Places a caption along the x-axis (again using the pgplot notation scheme).
- ycaption ``
caption
" = Places a caption along the y-axis (again using the pgplot notation scheme).
- copy = Sends a hardcopy of the current display to the defined printer. (On the Arecibo data taking computer
this is the printer in the control room.)
- copy ps2disk = Creates a postscript copy of the current display, placing it in the current
Analyz directory.
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