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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 IDL commands can be found online at http://www.naic.edu/phil/cordoc.html

Setting Up Analyz:

• corinfo = List the current set-up parameters. Assuming you're using the new correlator libraries, typing corinfo will cause the following defaults to appear:

  disp     =   1.000     (0-no,1-vs frq,2-vel)     f:fcidisp
  offset   =  0.2000     (offset   for disp=1)     f:fcioff
  print    =   1.000     (!=0-->print hdrinfo)     f:fciprint
  cals:      1.0000       1.0000
  set default values via func: corinfodef

  You can change any of there values by typing the associated variable (on the far right) followed by the value you wish to set it to. Thus if you want your data to be plotted against velocity by default, type ``fcidisp 2".
• corinfodef = set default values for corinfo. This command is useful when you just want to get back to the default corinfo values.
• setxterm = Set terminal to an xterm. This is pretty self-explanatory.
• scratch = Allocate memory for algebraic expressions. This is a necessary command to type, although if you have added an ``autoexecute" function to your libraries through using one of the staff-made sets of functions, it should be typed automatically. (You will know immediately if it isn't as you will get an error from Analyz telling you to type``scratch".)

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.

• atoldata = attach the online datafile
• attach <file> data = attach arbitrary data file (<file>)

Looking at Data:

• corget <scanNo.group> = Displays the requested data dump, or the next 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:

  1 - polarization A, all sub-correlators, no smoothing
  2 - polarization B, all sub-correlators, no smoothing
  

  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 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 calibrator 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 doit 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 argument lets Analyz choose the values
• hor <low> <high> = Set Low and high values for horizontal display (No argument 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.