AIPS quarterly report (Q2+Q3), 10 Sept 1998 ------------------------------------------- Personnel --------- Exchange visits between CV & AOC continue to be useful; Desai visited CV during May, Greisen spent a month in Socorro in June/July. Beasley began a 1-yr transfer to CV in July. There are ~4.5 full-time equivalent employees in the AIPS group. 15APR98 ------- The 15APR98 version of AIPS has been distributed to over 188 sites, running 198 installations (including Solaris, Linux, DEC Alpha, HP and SGI versions). The number of AIPS installations has grown impressively over the last year (33%, 15APR97-15APR98). Support for SunOS 4 pre-compiled binaries will be dropped in future releases. The majority of AIPS distributions are now received by ftp (82%), although a CD ROM distribution is now available, and is growing rapidly in demand. One attractive feature of the CD ROM is the ability to use the binaries directly from the CD, keeping only data and a small footprint (10MB) on the processing machine. This is particularly attractive for laptop computers. 15OCT98 ------- The TST version of AIPS 15OCT98 is currently distributed nightly to 26 sites throughout the US, Europe and Japan (22 automatically, 4 on request). At present the release of 15OCT98 is on schedule, at which time 15OCT97 (the pre-CVX "SPACE-VLBI" version) will no longer be available; full support for SVLBI processing has been available in 15APR98 and 15OCT98. Hardware -------- AIPS running on Linux PCs continue to show impressive absolute and cost-relative performance. NRAO recently received a shipment of Pentium II-400 systems and the AIPS group have performed preliminary benchmarks on them. The best AIPSMARK so far is 14.5 when the system is configured with 256MB of memory. The number comes out somewhat lower with 128MB (14.1) and 64MB (12.5). A new benchmarking suite will need to be produced within a year or two to more adequately measure the performance (current suite now completes in under 5 minutes, which may be too short to be representative). Support for DLT (digital linear tape) drives was added in 15APR98. Documentation ------------- At the present time we are converting the AIPS Cookbook from Tex to Latex, enabling conversion of the master Cookbook text to HTML. We plan to place the entire AIPS documentation system (Cookbook and all help documentation) on-line with full indexing and cross-referencing during 1998. Tasks to manipulate AIPS help files within browsers are now available in 15OCT98. General developments -------------------- 24-bit TV displays - From 15OCT98 and onwards a 24-bit XAS AIPS TV display is available on workstations whose graphics support 24-bit color. Multiple TV/Tek/MSG servers - 15OCT98 offers the option to have more than one set of TV/plot/message windows per workstation display and to support multiple displays (especially X terminals) from a single computer. FLGIT - A new task FLGIT was created to removed RFI interference from spectral-line data sets based on deviations from linear fits to the spectra or from median-window filtered spectra. This task has been primarily used to support the 74 MHz and P-band programs at the VLA. Y2K testing - Further Y2K testing of AIPS was performed by using the VLBA correlator to produce a dataset seemingly observed in February 2001. Loading the correlated data into AIPS did expose small deficiencies in date reading in tables. Calibration transfer - The VLBA correlator can now automatically attach flagging, system temperature, weather, gain curve and phase cal information to VLBA data sets. Detailed revision of the definition of the data tables and of the reader routines in FITLD was required to enable in-house testing of this capability. The format definition for FITS interferometry data (previously VLBA memo #108) is currently under revision. A serious bug in the frequency axis for lower sideband VLBA data was found and corrected during Q2. Interactive editing options have been added to EDITR and EDITA, allowing difmap-style editing of data sets. Using the g77 EGCS 1.0.3 compiler the AIPS group have now produced a native port of AIPS to Linux running on a DEC Alpha; AXLINUX will now be added to the list of supported architectures. Support of tasks to read VLBI Mark III data from the Bonn correlator has continued throughout 1998. Consolidation and version numbering of the tasks involved in porting VLBA correlator data to the USNO/GSFC Calc/Solve package has been undertaken during 1998 Q2-3, in particular the task CL2HF. The size of various AIPS internal memory spaces was increased to support a procedure set designed to calibrate and produce MERLIN images automatically. CONFI - A task CONFI was added to find optimal configuration of an array using the criteria of minimizing side lobes. This task has been written for MMA studies but can be used for general array design. SPLAT - The task SPLAT was created to reduce the size of data sets by allowing time and frequency-averaging when applying calibration, optionally producing single-source or another multi-source dataset.