Going AIPS: A Programmer’s Guide to the NRAO Astronomical Image Processing System Version 15 April 90 VOLUME 1 ABSTRACT This manual is designed for persons wishing to write programs using the NRAO Astronomical Image Processing System (AIPS). It should be useful for a wide range of applications, from making minor changes in existing programs to writing major new applications routines. All basic aspects of AIPS programming are dealt with in some detail. AIPS programmers: Bill Cotton — Image construction and applications routines Phil Diamond — Spectroscopy Chris Flatters — Polarization and VLBI Eric Greisen — TVs and AIPS Kerry Hilldrup — UNIX and Cray COS implementations Gareth Hunt — Data formats Bill Junor — VLBI Glen Langston — Imaging Nancy Maddalena — I^Tjjpt conversion Contents 1 Introduction 1-1 1.1 Scope ..........................................................................................................................................................1-1 1.2 Hey You, Read T h is ................................................................................................................................1-1 1.3 Philosophy ................................................................................................................................................1-2 1.4 An Overview of the AIPS System..........................................................................................................1-2 1.4.1 T a sk s .............................................................................................................................................1-3 1.4.2 V e rb s.............................................................................................................................................1-3 1.4.3 Data Files.......................................................................................................................................1-3 1.4.4 I/O ................................................................................................................................................1-3 1.5 S tyle.............................................................................................................................................................1-4 1.5.1 Precursor Comments................................................................................................................... 1-4 1.5.2 Body Com m ents..........................................................................................................................1-5 1.5.3 Indentation....................................................................................................................................1-5 1.5.4 CONTINUE Statem ents.............................................................................................................1-6 1.5.5 Statement N um bers....................................................................................................................1-6 1.5.6 Blanks.............................................................................................................................................1-6 1.5.7 Modular Code .............................................................................................................................1-6 1.5.8 Portability ....................................................................................................................................1-6 1.6 Language................................................................................................................................................... 1-7 1.6.1 FORTRAN....................................................................................................................................1-7 1.6.2 Statement O rd e r..........................................................................................................................1-8 1.6.3 INCLUDES....................................................................................................................................1-8 1.6.4 Dimension Declaration................................................................................................................1-9 1.6.5 SAVE Statements .......................................................................................................................1-9 1.7 Documentation..........................................................................................................................................1-9 1.7.1 User Documentation ................................................................................................................1-9 1.7.2 Programmer Documentation ....................................................................................................1-10 2 Skeleton Tasks 2—1 2.1 Data Modification Tasks — FUDGE and TAFFY.............................................................................2-1 2.1.1 FU D GE..........................................................................................................................................2-2 2.1.2 T A F F Y ..........................................................................................................................................2-4 2.2 Data Entry Tasks (UVFIL and CANDY) ..........................................................................................2-7 2.2.1 UVFIL ..........................................................................................................................................2-8 2.2.2 CANDY..........................................................................................................................................2-11 2.3 Modifying a Skeleton Task.......................................................................................................................2-13 3 Getting Started — Tasks 3—1 3.1 Overview ................................................................................................................................................... 3-1 3.2 The Cost of Machine Independence.......................................................................................................3-2 3.2.1 Character Strings..........................................................................................................................3-2 3.3 Task Name Conventions..........................................................................................................................3-3 i 3.4 Getting the Param eters.........................................................................................................................3-3 3.4.1 In AIPS (Help file)......................................................................................................................3-3 3.4.2 At Task Startup (GTPARM )...................................................................................................3-5 3.4.3 While a Task is Running (GTTELL)......................................................................................3-5 3.5 Restarting A IP S ......................................................................................................................................3-6 3.6 INCLUDE files.........................................................................................................................................3-6 3.7 Initializing Commons...............................................................................................................................3-7 3.7.1 Device Characteristics Common ............................................................................................3-7 3.7.2 Catalog Pointer Com m on.........................................................................................................3-8 3.7.3 History Common.........................................................................................................................3-9 3.7.4 TV Com m on...............................................................................................................................3-9 3.7.5 UV data pointer com m on.........................................................................................................3-9 3.7.6 Files common, DFIL.INC.........................................................................................................3-9 3.8 Input and Output File Names...............................................................................................................3-10 3.9 Copying Extension F iles.........................................................................................................................3-10 3.9.1 H isto ry .........................................................................................................................................3-10 3.9.2 Extension tables (ALLTAB, TABCOP) ................................................................................3-11 3.10 Communication with the u ser............................................................................................................... 3-11 3.10.1 Writing messages.........................................................................................................................3-11 3.10.2 Turning off system messages ...................................................................................................3-12 3.10.3 Writing to the line printer.........................................................................................................3-12 3.10.4 Writing to the Terminal (ZTTYIO) ......................................................................................3-13