GNU TeXmacs is a free wysiwyw (what you see is what you want) editing platform with special features for scientists. The software aims to provide a unified and user friendly framework for editing structured documents with different types of content: text, mathematics, graphics, interactive content. TeXmacs can also be used as an interface to many external systems for computer algebra, numerical analysis, and statistics. New presentation styles can be written by the user and new features can be added to the editor using Scheme.
Grlib is an implementation of generative grammars and turtle graphics. The grammars (Lindenmayer systems) are used to produce descriptions of three dimensional objects, and the turtle is used to display them (i.e., generate images in several forms, such as bitmap, PostScript, or OpenGL).
SIMPLE_1 (SIMulation Program for Logistics Engin'g) is a discrete/continuous network-oriented simulation language with general-purpose programming language features. The Linux version of this software includes a project management system to automate integration of user-developed C/C++ code into SIMPLE_1 network models. A user's C/C++ code is interfaced with the SIMPLE_1 modeling language through information embedded in comments in the user's header file(s). SIMPLE_1 produces executable files with the help of the C++ compiler.
DSP implements several low-level digital signal processing (DSP) primitives accelerated, when available, by the Intel/AMD SIMD instruction sets MMX/SSE/SSE2. Portable C versions are provided for compatibility on non-IA32 machines. Routines are provided to compute 16-bit integer dot products (FIR filtering, correlation); sum-of-squares (signal energy measurement), and peak sample detection (for automatic gain control, etc.).
Fnord is a mathematical visualization system. It provides a purely functional, collection-oriented language with symbolic differentiation and optimization. You can type in a parametric equation and see the resulting curve and/or surface. You can attach GUI widgets to parameters, change their values in real time, etc.