Calc is arbitrary precision arithmetic system that uses a C-like language. It's useful as a calculator, an algorithm prototype, and as a mathematical research tool. More importantly, calc provides a machine-independent means of computation. Calc comes with a rich set of builtin mathematical and programmatic functions.
Jmol is a Free, Open Source molecule viewer and editor. It is a collaboratively developed visualization and measurement tool for chemical scientists. Jmol is an active project, and there are new features being added to it on a daily basis. Users are encouraged to modify it to fit their needs and to contribute their changes to the project.
Sfront compiles MPEG 4 Structured Audio (MP4-SA) programs into efficient C programs that generate audio when executed. MP4-SA is a standard for normative algorithmic sound, which combines an audio signal processing language (SAOL) with score languages (MIDI and SASL). Under Mac OS X and Linux, sfront supports real-time, low-latency audio input/output and MIDI input. Under Mac OS X, sfront supports the creation of AudioUnit plug-ins. The documentation includes a book about SAOL programming.
DigitizeIt digitizes scanned graphs and charts. Graphs can be loaded in nearly all common image formats (including gif, tiff, jpeg, bmp, png, psd, pcx, xbm, xpm, tga, pct), pasted from the clipboard, or imported via a screenshot. Digitizing of line and scatter plots occurs automatically, and manual digitizing via mouse clicks is also possible. Data values are transformed to a specified axes system and can be saved in ASCII format, ready to use in many other applications such as Microcal Origin or Excel. Axes can be linear, logarithmic, or reciprocal scale. Multiple data sets can be defined and edited. Tilted and distorted graphs can be handled. Comprehensive online help is included. Java 1.4 is required.
The NumericalChameleon converts numbers with a precision of up to 1000 significant figures. It supports more than 3200 units in 82 categories, including lengths, areas, volumes, durations, bits & bytes, angles, temperatures, exchange rates, Roman numerals, spoken numbers, all 35 radixes, unicode, colorcode, int. dial codes, timezones, date calculations and more. You have unlimited access for adding, modifying, and deleting categories, units, and icons. Update exchange rates with the GUI or at the command line. All configuration data are stored in flat files.
The Chemistry Development Kit (CDK) is a library of Java classes for chemo-, bioinformatics, computational chemistry, and chemometrics. It provides important algorithms like substructure search, SMILES, Gasteiger charges, QSAR descriptor calculation, 3D structure generation, 2D layout and rendering, many IO formats, atom typing, and more.