LDPC-codes is a collection of programs and modules intended to support research and education concerning Low Density Parity Check (LDPC) codes. The decoding algorithm for LDPC codes is related to that used for Turbo codes, and to probabilistic inference methods used in other fields. Variations on LDPC and Turbo codes are currently the best practical codes known, in terms of their ability to transmit data at rates approaching channel capacity with very low error probability.
yacts, yet another continuous time simulator, uses J+ to interpret scripts, defining systems of ordinary differential equations, which it solves. J+ is a functional non-imperative simulation language with lazy evaluation, based on the J programming language, a dialect of APL. A program in J+ is a collection of (possibly functional) J assignment statements, just like a set of formulae on a sheet of paper. The interpreter, implemented as a software library, knows the interdependencies between these formulae and is able to compute any of the defined quantities with minimal effort, keeping track of the values which were already computed. The driver program (such as yacts) may ask the interpreter to compute certain quantities and set the values for others (propagating the changes to dependents).
h5tools provides third-party tools for working with data where the underlying storage object is HDF5. The toolkit currently has two utilities in it: The HDF5 NeXus writer API is a set of functions which allows writing data in the NeXus data format, using only HDF5 function calls. H5merge will merge any two HDF5 or NetCDF4 files.
WCSLIB is a C library, supplied with a full set of Fortran wrappers, which implements the "World Coordinate System" (WCS) standard in FITS (Flexible Image Transport System). It also includes a PGPLOT-based routine, PGSBOX, for drawing general curvilinear coordinate graticules, and a number of utility programs. The FITS "World Coordinate System" (WCS) convention defines keywords and usage which provide descriptions of astronomical coordinate systems in a FITS image header.