Ger van Diepen's Homepage

I work at ASTRON in Dwingeloo (The Netherlands) which is part of NWO.
ASTRON builds radio-astronomical hardware and software. The well-known Westerbork telescope is operated by ASTRON.

Currently I am working in the software development of ASTRON's LOFAR project, mainly in the development of a highly distributed version of the self-calibration and imaging software to cope with the terabyte-sized data output.
I have done part of this work at CSIRO's Australia Telescope National Facility (Sydney) as part of the ASKAP project.

I have developed major parts of the build environment for the LOFAR software which is based on the GNU autotools. A very useful recursive checkout/update and build tool has been developed, which can deal with CVS and Subversion.

Previously I have been working in the AIPS++ project. The main libraries of AIPS++ have been put into the new casacore project. The remainder has been put in the casarest package. A gzipped tarball can be downloaded (use right mouse button). Currently I'm spending only a small fraction of my time on casa/AIPS++ related work.

I am the main author of the casaTables data system, a relational database-like system. Its main features are:

• Support of multi-dimensional arrays. They can be stored in a tiled (aka chunked) way across table rows. The tile cache size is automatically set according to the access pattern.
• Table Query Language (TaQL) which is modeled after SQL. An important feature of TaQL is the built-in support for arrays and many functions on arrays (e.g. a running median). Also automatic unit conversion is supported.
• Columns can be stored (using various storage managers) or can be virtual (a la database views).
• Such data managers can be loaded dynamically from a dynamic library making the system very extensible.

I was also heavily involved in the development of the Lattices and Images modules. The Lattice Expression Language (LEL) is a very flexible means to form an expression of Lattices and Images (or subsets of them). It can deal with astronomical images in various formats (Table, Miriad, FITS). Recently I've added support for HDF5.

With Malte Marquarding (ATNF, Sydney) I have developed a Python binding to casacore called pyrap to be able to use casacore functionality directly from Python. It makes heavily use of Boost.Python

The main programming language I'm using is C++. At ASTRON I have developed the coding rules and guidelines for writing C++ code. Alas this was done in 1997 and has never been updated.
I have given a short presentation of the upcoming C++ standard (c++0x) which can be seen here. Another introduction can be found here. More information and an extensive list of references can be found on Wikipedia.

Scripting is done in Python and a bit of Glish.

Please send me email if you would like to have more information.