SMath Studio - Tiny, powerful, free mathematical program with WYSIWYG editor and complete units of measurements support.
MATLAB - A high-level language and interactive environment for numerical computation, visualization, and programming
Aspen Plus - Maximize profits using a plant-wide simulation solution that combines unparalleled accuracy and engineering collaboration with time-saving workflows.
Wolfram Mathematica - Mathematica has characterized the cutting edge in specialized processing—and gave the chief calculation environment to a large number of pioneers, instructors, understudies, and others around the globe.
DWSIM - DWSIM is an open-source CAPE-OPEN compliant chemical process simulator for Windows and Linux.
GNU Octave - GNU Octave is a programming language for scientific computing.