==GenPK== This is GenPK, a program to calculate the 3D matter power spectrum. To build, first make sure FFTW3 is installed on your system and that the headers are in your PATH. To build, type: make For the test suite (requires Boost::Test > 1.34), do: make test To run, do: ./gen-pk -i filename -o outputdir filename can be any Gadget snapshot, with or without the .o, in format I or II. For the doxygen-generated documentation, do: make doc To delete compiler output: make clean Further documentation may be found in the doxygen generated files in doc/html/index.html (type "make doc" to make this file), by typing ./gen-pk --help or in gen-pk.cpp Powerspectrum output is in Fourier units; to convert to, eg, Mpc/h, you should multiply k by 2 \pi / Boxsize and P(k) by (Boxsize/2\pi)^3, where Boxsize is the size of the box in Mpc/h. In addition, CAMB uses a different Fourier convention to FFTW (which GenPK is based on), so for comparison to CAMB you need to also multiply P(k) by (2\pi) ^3. The total conversion factors are then k *= 2\pi / Boxsize P(k) *= Boxsize ^3 A script to do this can be found in plot.py If you use this software in a paper, you can cite it via the ASCL: http://ascl.net/1706.006