Overview ======== This is a small C library for constructing initial data data for Brill waves (see e.g. http://arxiv.org/abs/gr-qc/9302023) to be used in 3+1 general relativity simulations. The construction involves solving an elliptic equation for the conformal factor. This is done using a pseudo-spectral method by expanding the conformal factor in the basis of SB functions (see Boyd 2000, chapter 17.9). The pseudo-spectral matrix is inverted with LAPACK. Building and installation ========================= The library requires LAPACKE (the C interface to LAPACK) to be present where the compiler and linker can find it. A C99-compliant compiler and a POSIX environment are expected. Simply running 'make' will then build the shared library libbrilldata.so. That must be copied manually to where your linker will find it (or set LD_LIBRARY_PATH accordingly on systems that support it). Usage ===== The public C API is described in the brill_data.h header. A simplistic Python wrapper using ctypes is also provided. It contains a single public class that takes the C context options as keyword arguments and solves the equation on initialization. The instance methods then allow to evaluate the solution where needed. Licence ======= This library is free software, available under GNU GPLv3 (see the LICENCE file for full licence text).