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3.8 Finding helpful information in AIPS

Much AIPS documentation can be displayed on your terminal by typing HELP word  C R, where word is the name of an AIPS verb, task or adverb. The information given will supplement that given in the INPUTS for a verb or task. It is the only source of information on the adverbs. Type XHELP word  C R to display the help file in your WWW browser with links to adverbs from task help files.

To print the HELP information on your line printer, set DOCRT = -1 and enter EXPLAIN word  C R instead. (Using DOCRT = 1 with EXPLAIN will send the output to your terminal screen.) For the more important verbs and tasks, EXPLAIN will print extra information, not shown by HELP about the use of the program, with detailed explanations, hints, cautions and examples.

HELP may also be used to list the names of all POPS symbols known to AIPS by category, an operation helpful when you can’t remember the name of something. Type:

> HELP ADVERBS C R

to get a list of all adverbs in the symbol table

> HELP ARRAYS C R

to get a list of all array adverbs in the symbol table

> HELP REALS C R

to get a list of all real adverbs in the symbol table

> HELP STRINGS C R

to get a list of all character string adverbs in the symbol table

> HELP VERBS C R

to get a list of all verbs, pseudo-verbs, and procedures in the symbol table

> HELP PSEUDOS C R

to get a list of all pseudo verbs in the symbol table

> HELP PROCS C R

to get a list of all procedures in the symbol table

In the past, AIPS contained a range of general HELP files which purported to list all verbs and tasks in various categories. Since these were maintained by hand, they were essentially never current and complete. That entire system has been replaced by the verbs ABOUT and APROPOS to be discussed below. A few general help files do remain, and they may even be relatively current. A list of these may be found by typing:

> HELP HELP C R

for help on HELP.

A few general help files remain. They are POPSYM (symbols used in POPS interpretive language ), NEWTASK (writing and incorporating a new task into AIPS), and PANIC (solutions to common problems).

The HELP verb is very useful, but only if you know that the function you want exists in AIPS and know its name. Two functions have appeared in AIPS to assist you in this search. The first of these, APROPOS, searches all of the one-line summaries and keywords of all AIPS help files for matches to one or more user-specified words. For example, type

> APROPOS  CLEAN  C R

to display all keyword and 1-line summaries of help files containing words beginning with “clean” (in upper and/or lower case), and

> APROPOS  ’UV PLOT’  C R

note the quote marks which are required if there are embedded blanks, or

> APROPOS  UV,PLOT  C R

to display all keyword and 1-line summaries of help files containing both words beginning with “uv” and words beginning with “plot.”

The text files used by APROPOS are maintained by the AIPS source code maintenance (check-out) system itself. As a result, they should always be current. Of course, the quality of the results depends on the quality of the programmer-typed one-line and keyword descriptions in the help files. These were not regarded as important previously and hence are of variable quality.

The second new method for finding things in AIPS is the verb ABOUT. Type

> ABOUT  keyword  C R

to see a list of all AIPS tasks, verbs, adverbs, etc. which mention keyword as one of their “keywords.”

You need only type as many letters of keyword as are needed for a unique match. The source-code maintenance system is used to force all help files to use only a limited list of primary and secondary keywords. Software tools to update the list files have also been written, and are used at least once with every AIPS release. The list of categories recognized is as follows (where only the upper-case letters shown in the name are actually used):

  ADVERB        POPS symbol holding real or character data  
  ANALYSIS      Image processing, analysis, combination  
  AP            Tasks using the "array processor"  
  ASTROMETry    Accurate position and baseline measurements  
  BATCH         Running AIPS tasks in AIPS batch queues  
  CALIBRATion   Calibration of interferometer uv data  
  CATALOG       Dealing with the AIPS catalog file  
  COORDINAtes   Handling image coordinates, conversions  
  EDITING       Editing tables, uv and image data.  
  EXT-APPL      Access to extension files (tables)  
  FITS          FITS format for data interchange  
  GENERAL       General AIPS utilities  
  HARDCOPY      Creating listings and displays on paper  
  IMAGE-UTil    Utilities for handling images  
  IMAGE         Transforming of images  
  IMAGING       Creation of images: FFT, Clean, ...  
  INFORMATion   General lists and user help functions  
  INTERACTive   Functions requiring user interaction  
  MODELING      Model fitting to uv or image data  
  OBSOLETE      Functions slated for removal  
  ONED          Functions for one-dimensional image slices  
  OOP           Tasks coded with object oriented principles  
  OPTICAL       Functions of interest for optical astronomy data  
  PARAFORM      Skeleton tasks for use in building new tasks  
  PLOT          Displays of image and uv data  
  POLARIZAtion  Calibration, analysis, display of polarization  
  POPS          Aspects of the AIPS’ user language POPS  
  PROCEDURe     Creation of and available procedures  
  PSEUDOVErb    Pseudo-verbs in the POPS language and AIPS  
  RUN           Creation of and available RUN files  
  SINGLEDIsh    Functions of interest for single-disk radio data  
  SPECTRAL      Functions for spectra-line and other 3D data  
  TABLE         AIPS table extension files  
  TAPE          Use of magnetic tapes (obsolete)  
  TASK          AIPS tasks - available asynchronous functions  
  TV-APPL       Tasks using the TV display  
  TV            Basic functions on the TV display  
  UTILITY       Basic functions on tables, uv and image data  
  UV            Functions dealing with interferometer uv data  
  VERB          Synchronous functions inside the AIPS program  
  VLA           Functions of particular interest for the VLA  
  VLBI          Functions of particular interest for very long  
                baseline data.

A variety of synonyms are also recognized. Besides those that are merely spelling variants, the currently accepted synonyms are

  FILES       ->  CATALOG           POSITION   ->  COORDINATES  
  FLAGGING    ->  EDITING           EXTENSION  ->  EXT-APPL  
  PRINTING    ->  HARDCOPY          PRINTER    ->  HARDCOPY  
  MAP         ->  IMAGE             MAP-UTIL   ->  IMAGE-UTIL  
  MAPPING     ->  IMAGING           LANGUAGE   ->  POPS  
  CUBE        ->  SPECTRAL          LINE       ->  SPECTRAL  
  VISIBILITY  ->  UV                VLBA       ->  VLBI  
  PARAMETERS  ->  ADVERB            HELPS      ->  INFORMATION  
  SLICE       ->  ONED

More detailed descriptions of new developments in AIPS can be found in the AIPSLetter published by the NRAO every six months and tied to each AIPS software release. It is available from the web site http://www.aips.nrao.edu/ and is included with AIPS distributions. An AIPS Memo series is published by the NRAO with details of various aspects of the implementation of, and planning for, AIPS. Advanced users may also wish to receive, and contribute to, the AIPS electronic mail forum — BANANAS. There is also an electronic news group called alt.sci.astro.aips devoted to AIPS matters. This AIPS CookBook, many of the AIPS Memos, and various other publications of the AIPS group are available via anonymous ftp (at ftp.aoc.nrao.edu) and via the Internet and the “World-Wide Web” starting with “URL” (Universal Resource Location) http://www.aips.nrao.edu/).

Your local AIPS Manager probably receives the AIPSLetter, AIPS Memos, and BANANAS and can make information from them available at your site. He/she should also be aware of the electronic means of information retrieval, and be able to help you use them. If this is not the case, write to the AIPS Group (at NRAO, P. O. Box O, Socorro, NM 87801-0387) or send electronic mail to daip@nrao.edu for further information about these services.

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