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.
Cactus is a general, modular, parallel environment for solving systems of partial differential equations. The code has been developed over many years by a large international collaboration of numerical relativity and computational science research groups and can be used to provide a portable platform for solving any system of partial differential equations.
TRIP is a general computer algebra system dedicated to celestial mechanics. It includes a numerical kernel and has interfaces to gnuplot and xmgrace. Computations can be performed with double, quadruple, or multi-precision. Users can dynamically load external libraries written in C, C++, or Fortran. Parallel computations on multivariate polynomials can be performed.
SHTns is a high-performance Spherical Harmonic Transform library. It was designed for numerical simulation (fluid flows, mhd, etc.) in spherical geometries, but can be used for any kind of problem involving scalar or vector spherical harmonics. It is very fast, thanks to careful vectorization and runtime tuning. It supports multi-threaded transforms via OpenMP. It features scalar and vector transforms, synthesis and analysis, and flexible truncation and normalization. A Python interface is included.
xd3d is a simple scientific visualization tool designed to be easy to learn. It can plot 2D and 3D meshes, with shadowing, contour plots, vector fields, iso-contour (3D), as well as 3D surfaces z=f(x,y) defined by an algebraic expression or a cloud of points. It generates high-quality vector PostScript files for scientific publications and still or animated bitmap images. The distribution includes the graph plotter, xgraphic.
Orpie is a fullscreen RPN calculator for the console. Its operation is similar to that of modern HP calculators, but data entry has been optimized for efficiency on a PC keyboard. Features include extensive scientific calculator functionality, units support, base conversions, command completion, configurable keybindings, and a visible interactive stack.
Calcoo is a scientific calculator designed to provide maximum usability. Its features bitmapped button labels and display digits to improve readability, no double-function buttons, undo/redo buttons, copy/paste interaction with the clipboard, both RPN and algebraic modes, two memory registers with displays, displays for Y, Z, and T registers, and tick marks to separate thousands. Calcoo is written in C using the GTK+ widget library (v.2.2+).