NLopt is a library for nonlinear optimization that allows one to select from a wide variety of optimization algorithms by changing a single parameter. Its features include both local and global optimization, unconstrained, bound-constrained, or nonlinear-inequality constrained problems, and optimization using function values only or using derivatives if they are available. It was initially begun as a wrapper around several existing optimization packages, but it now also includes original implementations of several algorithms for which no free code was available. It provides interfaces callable from C/C++, Fortran, Matlab, GNU Octave, Python, and GNU Guile.
PyParticles is a particle simulation toolbox entirely written in Python. It simulates a particle-by-particle model with the most popular integrations methods, including Euler, Runge Kutta, and Midpoint. It represents the results on an OpenGL or Matplotlib plot, and offers an easy-to-use API.
The mctdhtools project aims to provide a set of routines for easily reading and manipulating the output of the Heidelberg MCTDH code. Its goal is to allow a new user to quickly get started with writing custom analysis programs, and to allow more experienced users to write small, clean, and testable analysis programs, something that seems incompatible with the Fortran-77 code of the Heidelberg MCTDH package.