High Resolution Trajectory Compression (HRTC) is a method for efficient storage of trajectories from particle simulators (e.g. molecular dynamics, or agent based systems).

This code builds a stand-alone program and a library for integration into other programs. Both are fully functional research prototypes.

• integer-encoding-library (included as sub-module)
• for the stand-alone program: libboost-program-options (part of boost)
• for the library: our fork of trajectory-ng, residing in the same parent directory as this repository

The software has only been tested on 64bit GNU/Linux systems using GCC.

First set up the integer-encoding-library:

git submodule init
git submodule update
(cd integer_encoding_library && make)

Then run make bin, make lib, or just make to build the stand-alone program (hrtc), the library (hrtc_wrapper.o), or both, respectively.

As uncompressed I/O format hrtc uses either tab-separated-values (one time-step per line) or an awkward yet-to-document binary format.

Use

./hrtc --compress --format tsvfloat --numtraj 42 --bound 23 --error 0.1 \
    --src original_file --dst compressed_file

to compress and

./hrtc --decompress --format tsvfloat --numtraj 42 --bound 23 --error 0.1 \
    --src compressed_file --dst uncompressed_file

to decompress your data. The number of trajectories (rows per line) has to be specified with --numtraj as well as the maximal absolute value occurring in the trajectory (e.g. your bounding box) with --bound. Most important is the --error which specifies the maximal distance of a particle between compressed and original representation.

Further parameters that can be tuned are --blocksize, --integer-encoding, and the --qp-ratio. The last is a value between 0 and 1 the specifies how the error budget is split between quantization error and approximation error.

The code is released under the GPL version 3 license (see file LICENSE).

The authors can be contacted via email and jabber at jh@sotun.de.