Gnu Octave

Open Source Computation Tool

GNU Octave is a high-level interpreted language, primarily intended for numerical computations. It provides capabilities for the numerical solution of linear and nonlinear problems, and for performing other numerical experiments. It also provides extensive graphics capabilities for data visualization and manipulation. Octave is normally used through its interactive command line interface, but it can also be used to write non-interactive programs. The Octave language is quite similar to Matlab so that most programs are easily portable.

KAlgebra

Open Source Calculator

KAlgebra is a calculator with symbolic and analysis features that lets you plot 2D and 3D functions as well as to easily calculate mathematical expressions. KAlgebra is a MathML-based graphic calculator, thought to bring to the user its power by solving expressions written in MathML or calculating converted common equations to MathML.

GraphCalc

Open Source Calculator for Windows

GraphCalc is an open source computer program that runs in Microsoft Windows and Linux that provides the functionality of a graphing calculator.

Graphviz - Graph visualization

Graphviz is open source graph visualization software. Graph visualization is a way of representing structural information as diagrams of abstract graphs and networks. It has important applications in networking, bioinformatics, software engineering, database and web design, machine learning, and in visual interfaces for other technical domains.