This software implements a number of lossless smart meter data compression algorithms and can also be used to evaluate them. If you use this software, please cite

[1] Andreas Unterweger and Dominik Engel. Resumable Load Data Compression in Smart Grids. IEEE Transactions on Smart Grid, 6(2):919-929, March 2015.

[2] Andreas Unterweger, Dominik Engel, and Martin Ringwelski. The Effect of Data Granularity on Load Data Compression. In Energy Informatics 2015 - 4th D-A-CH Conference, EI 2015, volume 9424 of Lecture Notes in Computer Science, pages 69-80. Springer International Publishing, Switzerland, November 2015.

These papers are also available as BibTeX entries in the papers.bib file for convenience.

This software comes with no warranty whatsoever. You may use it without charge, as long as the original copyright notices remain and the papers listed above are cited. See the LICENSE file for details.

On Windows, start Visual Studio 2013 and open DataCompressor/build/MSVC/DataCompressor.sln. Build the solution, i.e., all projects. Other versions of Visual Studio may work fine, but are currently not supported explicitly.

On Linux, make sure that GNU Make 3.81 and gcc 4.8.4 are installed. Navigate to DataCompressor/build/gcc and type make. Other versions of GNU Make and gcc may work fine, but are currently not supported explicitly.

This software has been tested on Intel x86-64 and ARM v7 precessors (Raspberry Pi 2). On Windows, both 32-bit and 64-bit versions of the software work out of the box. On Linux, gcc-specific parameters can be added to DataCompressor/common/build/gcc/common.mak (e.g., COMMON_CFLAGS) to build for a different "bitness" than the compiler/target default.

The front-end of the software is DCCLI, a command line interface for Data Compressor, which resides in the folder named DCCLI. There is a short description of the software in DataCompressor/DCCLI/doc/readme.md. Apart from that, the software itself outputs notes on usage when called without arguments or with incorrect ones.

Always use the release version of the software when evaluating algorithms. On Linux, you can use make test in either DataCompressor/build/gcc/ or DataCompressor/DCCLI/build/gcc/ to compress the supplied test file with the DEGA algorithm [1] and decompress it again for verification.

Here are some example calls for the evaluation from [2] for the MIT REDD data set, where each channel is first pre-processed using

./DCCLI "$c" "$temp_ref" decode csv separator_char=' ' column=2 # encode csv

where $c is the input channel file name and $temp_ref is the output file name of the pre-processed file. To process this file to a compressed output file, $temp_out, proceed as follows:

For DEGA coding, use ./DCCLI $temp_ref $temp_out decode csv # encode normalize # encode diff # encode seg # encode bac adaptive

For LZMH coding, use ./DCCLI $temp_ref $temp_out encode lzmh

For A-XDR coding, use ./DCCLI $temp_ref $temp_out decode csv # encode normalize

For combined compression and decompression, use, e.g., for DEGA: ./DCCLI $temp_ref $temp_out decode csv # encode normalize # encode diff # encode seg # encode bac adaptive # decode bac adaptive # decode seg # decode diff # decode normalize # encode csv

The software allows specifying small(er) bit sizes for I/O and processing.

For I/O, the option IO_SIZE_BITS documented in DataCompressor/common/doc/overview.txt can be set to reduce the I/O bit size. On Linux, you can set IO_SIZE_BITS in DataCompressor/common/build/gcc/ to a corresponding value for convenience. In the debug version of the software, the number of usable bits for I/O is printed on application startup.

For processing, most encoders/decoders have parameters like the block size or the value size (in bits). The parameters of each encoder are described in DataCompressor/DCLib/doc/readme.md. Other parameters like memory buffer sizes are documented in DataCompressor/DCCLI/doc/readme.md.

The software is split into separate projects with an according folder structure. Each project has a short description in $project_name/doc/overview.txt. $projectname DCCLI is the Data Compressor command line interface for the data compression library, DCLib, which uses the I/O library DCIOLib. The commonly shared code can be found in the folder DataCompressor/common/.

When modifying the software, make sure to build the debug versions of all projects. In Visual Studio, this can be done by choosing the Debug configuration and rebuilding the solution. With GNU make, make debug builds a debug version.

Note that, by default, debug and release versions cannot be built simultaneously at the moment using the Makefiles. When switching between debug and release versions, make sure to call make clean in between. If you wish to build some of the projects in their debug version, it is possible to use the Makfiles in $project_name/build/gcc individually with make debug (or make).

If you modify the software, please keep it mostly C90-compliant, as assured by the Makefile options in DataCompressor/common/build/gcc/. This is done for compatibility reasons (older Visual verisons and architectures with compilers that do not support C99).