To:      Phyllis Jackson

From:    Eric Greisen

Date:    "1 October 1995"

Subject: Quarterly Report on AIPS (1995 Q3)

     The first release of AIPS under a "GNU General Public License"
rather than a "user agreement" took place during this quarter.  The
15JUL95 release became available through anonymous ftp on August 18.
The source code and full binary forms for a variety of architectures
are found in directory aips/15JUL95 (and below) on the computer known
as baboon.cv.nrao.edu.  Since then, 67 sites have copied some or all
of AIPS to their machines.  To provide more information on AIPS use,
and to provide data which will allow us to set priorities, a
registration system has been established. Although the AIPS code is
now free and anonymous, help with installation and use of AIPS
requires a site "registration" which is also at no charge to
institutions engaging in research in astronomy.  To date, 37 non-NRAO
sites have registered the 15JUL95 release, indicating that they expect
to run it on 223 computers.  Tape copies of AIPS are also available,
currently without a media charge. So far 27 copies have been shipped
on tape to 18 sites.

     The change to a GNU license not only simplifies portions of the
distribution.  It also allows us to use other peoples' code directly
when that code is also released under a GNU license.  We are creating
a GNU directory tree within the AIPS directory structure to support
the inclusion of GNU-licensed software.  The first such package is the
"readline" routines used by the Bash shell to handle terminal input.
(Korn and other Unix shells have similar functionality.)  Users of
15JAN96 AIPS now have emacs-like (or vi-like) commands to edit the
current input line, to recover and edit previous input lines, and even
to do symbol completion in which a partially-typed symbol is completed
by the readline software when the Tab key is hit (or a list of
possible completions is shown).  This function even knows that a task
name cannot be the first symbol on a line.

     The re-write of the CookBook continued during the quarter at a
slower pace.  The big change was the addition of an Index to all
chapters of the CookBook.  Appendix Y on file sizes was re-written and
several chapters had minor revisions made to reflect the most recent
changes in AIPS.  All chapters of the CookBook are made available via
the World Wide Web.  Users can fetch the new chapters as they are
actually completed by fetching the files via the WWW (or via anonymous
ftp).  AIPS is at WWW URL http://www.cv.nrao.edu/aips/.

     VLBA data processing received a lot of attention during the
quarter.  Two new polarization tasks were contributed by Kari
Leppanen: BLAVG which allows a more robust estimation of differential
polarization delay offsets and LPCAL which calibrates polarization,
allowing for spatial structure in the calibrator source.  The new task
PCCOR generates calibration data from the pulse-cal table to correct
the instrumental delay and phase offsets between individual baseband
converters.  Also added was a more robust and complete method of
correcting for amplitude losses due to averaging and FFTs prior to
complete delay correction.  The new task SNEDT allows interactive
editing and smoothing of calibration tables using the TV display.  A
preliminary version of OMFIT was submitted by Ketan Desai, Naval
Research Laboratory, to combine self-calibration with uv-plane model
fitting. The plot task VPLOT was generalized to allow automatic data
editing and to improve performance still further.

     Of interest both to VLA and to VLBA, the new task FIXWT
determines proper uv-data weights by estimating the noise in the data.
Spectral bandpass calibration will soon be made more flexible with
improved signal-to-noise using polynomial fits to the bandpass rather
than channel-by-channel averaging.  The AIPS tasks which support the
12m on-the-fly imaging mode were enhanced to allow time smoothing,
additional channel selection, and a wider range of convolution
functions.  PostScript display tasks were given the COPIES adverb,
LWPLA was changed to use the full grey-scale range (avoiding a TeX
bug), and TVRGB was given the ability to write a full-color PostScript
output   The AIPS user-number conversion procedures EHEX and REHEX
were made available also as verbs inside AIPS.


File: /home/primate/egreisen/AIPS/reports/QRep95c.TXT