To:      Phyllis Jackson

From:    Eric Greisen

Date:    "1 January 1995"

Subject: Quarterly Report on AIPS (1994 Q4)

     By 28 December 1994, the 15JUL94 release of "Classic AIPS" had been
shipped to 72 institutions, 38 by magnetic tape and 34 by electronic
copies.  The increase in the use of magnetic tape has been caused by
our offer to shorten the installation process by sending a full binary
copy of AIPS on tape.  The binary versions are currently available for
SunOS, Solaris (Sun), AIX (IBM), OSF/1 (DEC Alpha), Linux (PCs), and
SGI.  The transfer of Phil Diamond to the aips++ project from the AIPS
programming group in Socorro will now be done more slowly and
tentatively than originally planned.

     The substantial work of rewriting the user manual called the
"AIPS CookBook" continued during the quarter.  Completely rewritten
chapters on displaying your data and spectral-line software were
released during the quarter and an additional one on VLBI data is in
the last stages of editing.  New chapters treating introduction to
AIPS, basic tools, calibration, program lists, and the use of NRAO
facilities were completed for the 15JUL94 release.  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).

     The most noticeable change to AIPS during the quarter was our
first major file format change in 5 years.  Actually, the change was
comparatively minor, involving only the names of files, not their
contents.   The change was in the number base used in file naming,
from 16 to 36 (0-9,A-Z).  This extended hexadecimal allows us to
support user numbers higher than 4095 and, with the addition of
another character to the file names, to support file up to 46655
extension files rather than a mere 255.  The latter was a serious
limitation to spectral-line data reduction.  This change also allows
us to support up to 35 disks, rather than 15, for each AIPS user and
raises other limits as well.

     During the quarter, three new tasks were added to Classic AIPS.
VPLOT is a new, much faster task to plot visibility data and/or models
with multiple baselines per plot page.  PCLOD reads the file
containing phase-cal information produced by the VLBA correlator.  The
resulting PC file can now be plotted by SNPLT and will soon be used to
calibrate VLBA data.  The third new task, MOVE, is a long overdue one
to copy or move image or uv data between users (i.e. to different user
numbers).

     Pre-existing tasks also received significant attention.  The most
complex change, which was completed and improved during this quarter,
involved fixing bandpass calibration for the time-dependent shifts in
bandpass introduced by the VLBA correlator.  Another tricky
improvement was the addition of amplitude corrections for VLBI data
which were averaged in frequency and time while still being affected
by residual delay and rate errors.  A subtle bug in holding the mean
gain modulus constant in self-calibration was fixed.  Single-dish
on-the-fly imaging was speeded up and enhanced by the addition of
support for it in all flagging tasks.  An input format bug was also
corrected.  The interactive uv data flagging tasks were improved by
making the production and averaging of the master grids more reliable.
More Clean boxes (50) are now available, including Clean boxes in the
secondary images (50/image but in WFCLN only).


File: /home/primate/egreisen/AIPS/reports/QRep94c.TXT