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C++ PostScript Prolog
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psa - Point Set Analysis A tool for the analysis of two-dimensional point sets with applications in graphics. Overview psa is a command line tool that takes two-dimensional point sets as input and analyzes these point sets with respect to several spatial and spectral statistics important for sampling problems in computer graphics. These statistics include: - Global minimum distance (smallest separation between any two points) - Average minimum distance (average nearest-neighbor distance) - Bond-orientational order (similarity to the hexagonal lattice) - Effective Nyquist frequency (equivalent to Nyq. freq. in uniform sampling) - Oscillations (metric for potential aliasing caused by the point set) - Radial power spectrum - Radial distribution function - Anisotropy - Fourier amplitude/power spectrum For more information regarding these measures, consult our papers: Daniel Heck, Thomas Schl\"omer, Oliver Deussen: Blue Noise Sampling with Controlled Aliasing. ACM Trans. Graph., 32(3):25:1-25:12, 2013. Thomas Schl\"omer, Oliver Deussen: Accurate Spectral Analysis of Two-Dimensional Point Sets. Journal of Graphics, GPU, and Game Tools, 15:3, 152-160, 2011. The latest version of psa can always be found at https://github.com/nodag/psa. Any suggestions regarding the concepts or the implementation of psa are very welcome. Feel free to contact us via http://thomas-schloemer.org. Dependencies - cairo (http://www.cairographics.org) for PDF and PNG output - CGAL (http://www.cgal.org) for the bond-orientational order The CGAL dependency is not strict and can be removed by setting HAVE_CGAL to 0 in the accompanying Makefile. The computation of the bond-orientational order is then omitted. psa also makes use of OpenMP if available. Usage Type ./psa filename [options] to analyze the given file(s). When called without any parameters, psa generates a single PDF containing all measures. Use --avg if you want to average all measures over the given files, e.g. ./psa --avg points/mypoints*.txt Type ./psa --help for a list of available options. File Formats Point set files are supported in three flavors: - TXT: plain text files with a pair of coordinates for each point - RPS: raw single-precision floating point data - EPS: coordinate pairs for each point with a basic EPS header that is understood by most EPS viewers An example for each format is included in /points. Use --convert to convert files between the three formats. Note that psa cannot read arbitrary EPS files. License and Acknowledgements psa is free software and published under the GNU GPL. For further information see the file COPYING. This software has been partially funded by DFG, German Research Foundation, and the PhD Program 'Explorative Analysis and Visualization of Large Information Spaces'. Copyright (C) 2011-2015 Thomas Schl\"omer Daniel Heck Version History v1.1a - Fixed some Linux/gcc compile issues v1.1 - Made oscillations metric independent of effective Nyquist frequency; the metric is now in line with the upcoming ACM TOG paper v1.0 - psa has been totally rewritten - Added new statistics: effective Nyquist frequency, oscillations metric, and orientational order (the latter needs CGAL) - Added new 1D measure next to radial power spectrum and anisotropy: radial distribution function - Added option --raw to write the raw data of all 1D measures for better post-processing using external tools - 1D measures are now written as TEX source files based on the TIKZ package for cleaner integration into larger documents and potential final touches - Added options to generate every measure separately - Added configuration file 'common/psa.cfg' for most important variables - Can now directly read points from certain EPS files next to TXT and RPS - Added option --convert to convert points between these formats - Dropped need for fftw-library - Dropped computation of star discrepancy v0.2.2 - Added average mindist measure - Removed non-toroidal distance measure - Normalized radius is now called normalized mindist - Changed default plot colors to black - Improved code readability v0.2.1 - Bug fixes with respect to cairo version >1.10.0 - Fixed some MS VS compilation issues v0.2 - Integrated an optional DFT using the fftw-library - Non-spectral measurements are now also rendered into summary files - Added non-toroidal minimum distance computation - Support for more arbitrarily many point sets in a single directory - Bug fixes v0.1 - Initial release