Python matplotlib is a for 2D plotting publication-ready figures in various formats, or rendering them interactively cross-platform. It can be scripted or used in Pythons interactive shell, within web applications, or through bindings with multiple GUI toolkits. It simplifies plot generation, histograms, power spectra, bar charts, error charts, scatter plots. Typical uses only require a few lines of code, while complex rendering is kept feasible. Its pyplot interface provides a MATLAB-style API.
MathMod is a mathematical modeling software to visualize and animate implicit and parametric surfaces, either with 3D or 4D hypersurface plotting. It provides JSON-compatible scripting facilities, OBJ and K3DSurf format export or .js conversion, ready-to-use animation algorithm examples, and includes a simple editor.
Functy is a 3D graphics generation tool. It plots cartesian, spherical or parametric curve functions. It allows altering their parameters for immediate redraws to explore 3D function results. It utilized GPU functions entirely for visualization.
SCaVis is an environment for scientific computation, data analysis and data visualization designed for scientists, engineers and students. While itself implemented in Java, it provides bindings for Jython, Groovy, JRuby, BeanShell or Matlab/Octav for symbolic calculations. It features chart plotting, histograms, advanced statistics, symbolic calculations, data analysis, mathematical functions, data mining, linear algebra and plots.