The GNU Autoconf Archive is a collection of more than 450 macros for GNU Autoconf. They can be re-used without imposing any restrictions on the licensing of the generated configure script. In particular, it is possible to use them in configure scripts that are meant for non-free software.
GNU ddrescue is a data recovery tool. It copies data from one file or block device (hard disk, CD-ROM, etc.) to another, trying hard to rescue data in case of read errors. GNU ddrescuelog is a tool that manipulates ddrescue logfiles, shows logfile contents, converts logfiles to/from other formats, compares logfiles, tests rescue status, and can delete a logfile if the rescue is done.
GNU Moe is a powerful, 8-bit clean console text editor for ISO-8859 and ASCII character encodings. It has a modeless, user-friendly interface, online help, multiple windows, unlimited undo/redo capability, unlimited line length, global search/replace (on all buffers at once), block operations, automatic indentation, word wrapping, filename completion, a directory browser, duplicate removal from prompt histories, and delimiter matching.
CGAL, the Computational Geometry Algorithms Library, is a large C++ library of geometric data structures and algorithms such as Delaunay triangulations, mesh generation, Boolean operations on polygons, and various geometry processing algorithms. CGAL is used in various areas: computer graphics, scientific visualization, computer aided design and modeling, geographic information systems, molecular biology, medical imaging, robotics and motion planning, and numerical methods.
The minfx project is a Python package for numerical optimization. It provides a large collection of standard minimization algorithms, including the line search methods (steepest descent, back-and-forth coordinate descent, quasi-Newton BFGS, Newton, and Newton-CG), the trust-region methods (Cauchy point, dogleg, CG-Steihaug, and exact trust region), the conjugate gradient methods (Fletcher-Reeves, Polak-Ribiere, Polak-Ribiere +, and Hestenes-Stiefel), the miscellaneous methods (Grid search, Simplex, and Levenberg-Marquardt), and the augmented function constraint algorithms (logarithmic barrier and method of multipliers).
Lbzip2 is a parallel, SMP-based, bzip2-compatible compression utility, with a commandline resembling that of the original bzip2. It is usable both on its own and as a filter passed to GNU tar with the "--use-compress-program" option. It uses Gnulib, and its building and testing process is managed by the GNU build system. Starting with release 2.0, lbzip2 is independent of libbz2 and features yambi, an independent BWT compression stack with improved speed and robustness.
Lzip is a lossless data compressor based on the LZMA algorithm, with very safe integrity checking and a user interface similar to the one of gzip or bzip2. Lzip decompresses almost as quickly as gzip and compresses better than bzip2, which makes it well suited for software distribution and data archiving. If you ever need to recover data from a damaged lzip file, try the lziprecover program.
The fstrcmp library provides an fstrcmp function that returns a number between 0.0 (nothing alike) and 1.0 (identical); this can be used to suggest likely alternatives in error messages. Fuzzy comparisons for byte arrays, wide character strings, and multi-byte character strings are also available. In addition, there are integer alternatives for systems with slow floating point emulation.