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Tools in AIPS++

AIPS++ is a tool-based reduction package where related functions are gathered into `tools'. The user creates a working version of a particular tool by logically associating it with a dataset and giving the tool (data + functionality) a name. The different capabilities of this tool are then accessed by running one or more functions within that tool. For example, to plot calibration solutions, you would first create a calibration tool and run the associated plotcal function. This involves the following steps:

• Create a calibrater tool attached to your dataset. Specify the TOOLNAME to be cal & FILENAME to be mydata.ms,

• Select the function plotcal, choose PLOTTYPE to be AMP and TABLENAME to be cal.solutions (e.g. the table with calibration solutions). Leave remaining parameters to their defaults to produce a plot of calibration solutions versus time;

• When you are finished with the tool, remove the tool and detach it from the dataset, mydata.ms.

To execute this sequence, type at the Glish command line prompt:

include 'calibrater.g';                   # Include the calibrater tool
cal:=calibrater(data='mydata.ms');        # Create a calibrater tool
                                          #   for the data 'mydata.ms'
                                          #   and call it 'cal'
cal.plotcal(plottype='amp',               # Execute the function plotcal
            tablename='cal.solutions');   #   specifying parameters
                                          #   plottype & tablename
cal.done();                               # End use of tool

All tools have a Done function which undoes the explicit association of the tool and data.

To see what parameters are associated with the plotcal function (or any function or tool in AIPS++ go to:   http://aips2.aoc.nrao.edu/stable/docs/user/documentation.html
The User Reference Manual gives a listing of each parameter with some examples. Detailed help on Synthesis calibration and imaging can be found in the ``Generic Processing'' chapter. The ``Basic Tools'' chapter gives details on Plotting, image display and analysis.

When working from the Glish command line in AIPS++, basic tools for VLA data reduction and imaging must be initialized first. Type at the Glish command prompt:

include 'vlafiller.g';      
include 'ms.g';             
include 'flagger.g';
include 'imager.g';
include 'msplot.g';
include 'calibrater.g';
include 'image.g';
include 'imagepol.g';      
include 'viewer.g';

A note about Glish syntax: Notice the semi-colon at the end of each Glish line? This is an explicit end-of-line indicator that tells Glish that you are finished with the inputs. Although it is not necessary, it can be helpful. For instance, say you are typing in a long series of inputs for a tool, you have made multiple carriage returns, you think you are done but Glish is just sitting there waiting for more inputs. What goes? Well, you probably made a typo somewhere along the way. So, just type a semi-colon at the command line prompt to force an end-of-line. You will then get an error message telling you that the syntax is wrong. Fix the syntax error, re-submit the command and AIPS++ will start execution.

It is also convenient to start up a viewer tool to view and analyze images easily. To start the default viewer type:

include 'viewer.g';        # Include the viewer tool
dv.gui();                  # Start up the default viewer (dv) GUI

You will get two popup GUIs displayed, the viewer Display Panel and the viewer Data Manager panel that you can use to select and view any AIPS++ or FITS image (Fig. 1.2). You can put these off to the side until you are ready to use them or left-click on their Done buttons to close the tools. Note: once the aipsinit.csh file has been sourced, you can start the viewer directly from the UNIX prompt by typing viewer.

Figure 1.2: AIPS++viewer and data manager GUI for displaying images.