LMDB is an ultra-fast, ultra-compact key-value data store developed by Symas for the OpenLDAP Project. It uses memory-mapped files, so it has the read performance of a pure in-memory database while still offering the persistence of standard disk-based databases, and is only limited to the size of the virtual address space (it is not limited to the size of physical RAM).
ack is a tool like grep, optimized for programmers. Designed for programmers with large heterogeneous trees of source code, ack is written purely in portable Perl and takes advantage of the power of Perl's regular expressions. It searches entire trees by default while ignoring Subversion, Git, and other VCS directories and other files which aren't your source code. It uses Perl regular expressions to find just what you want.
ENet for C# wraps the C-language ENet networking library. For games and other realtime applications, if you use TCP, old data can hold up newer data, even if it is no longer relevant (old positions, etc.). Your players will perceive any lost packet as a "lag burst". ENet supports multiple in-order streams of data, and allows you to decide on reliability on a per-packet basis. The library is useful for both client-server and peer-to-peer architectures.
Capsule Tree is a general purpose, self-balancing tree data structure for large, ordered data sets. It is designed to provide the same characteristics as B-trees and B+trees, but built from the ground up for in-memory usage. In other words, there are no provisions for “slow” I/O cases. The original motivation for this tree was a better backend for memory managers. However, the end result was a new sub-category of trees.
QtWebSockets is a pure Qt implementation of WebSockets, both client and server. It is implemented as a Qt source code module (.pri file) that can easily be embedded into existing Qt projects. It has no dependencies other than Qt. It features text and binary sockets, frame-based and message-based signals, proxy support, and strict Unicode checking.
Pascal-P4 for Free Pascal and Delphi is a port of a Pascal compiler written at ETH Zurich in 1976. The source code of the compiler is documented in the book "Pascal Implementation" by Steven Pemberton and Martin Daniels. The purpose of this project is to make Pascal-P compilable by Free Pascal and Delphi while keeping the changes to a minimum and preserving the line numbering as much as possible.
MLPACK is a C++ machine learning library with an emphasis on scalability, speed, and ease-of-use. Its aim is to make machine learning possible for novice users by means of a simple, consistent API, while simultaneously exploiting C++ language features to provide maximum performance and maximum flexibility for expert users. It contains algorithms such as k-means, Gaussian mixture models, hidden Markov models, density estimation trees, kernel PCA, locality-sensitive hashing, sparse coding, linear regression and least-angle regression.