The Clusutils package contains programs to assist researchers in their study of data clustering problems and algorithms. The clusgen program generates artificial data sets. The cluscomp program compares partitions of a data set, and returns an index (between plus/minus 1) which is a measure of the correspondence of the partitions with each other.
CwMtx is a library written in C++ that provides the matrix and vector operations that are used extensively in engineering and science problems. A special feature of this library is the quaternion class which implements quaternion math. Quaternions are very useful for attitude determination in 3D space because they do not suffer from singularities. Furthermore, successive rotations and transformations of vectors can be accomplished by simple quaternion multiplication. Attitude dynamics can be expressed in a very compact form using quaternions
GiNaC (GiNaC is Not a CAS (Computer Algebra System)) is a C++ library for symbolic calculations. It is designed to allow the creation of integrated systems that embed symbolic manipulations together with more established areas of computer science (like computation-intense numeric applications, graphical interfaces, etc.). Contrary to other CASes it does not try to provide extensive algebraic capabilities and a simple programming language but instead accepts a given language (C++) and extends it by a set of algebraic capabilities.
Yacas is a general purpose, easy to use Computer Algebra System (a CAS is a program that can be used to do symbolic manipulation of mathematical expressions). It is built on top of its own programming language designed for this purpose, in which new algorithms can easily be implemented. In addition, it comes with extensive documentation on the functionality implemented and methods used to implement them.