The 2DECOMP&FFT library is a software framework in Fortran to build large-scale parallel applications. It is designed for applications using three-dimensional structured mesh and spatially implicit numerical algorithms. At the foundation, it implements a general-purpose 2D pencil decomposition for data distribution on distributed-memory platforms. On top, it provides a highly scalable and efficient interface to perform three-dimensional distributed FFTs.

APBS is a software package for the numerical solution of the Poisson-Boltzmann equation (PBE), one of the most popular continuum models for describing electrostatic interactions between molecular solutes in salty, aqueous media. Continuum electrostatics plays an important role in several areas of biomolecular simulation, including simulation of diffusional processes to determine ligand-protein and protein-protein binding kinetics, implicit solvent molecular dynamics of biomolecules, solvation and binding energy calculations to determine ligand-protein and protein-protein equilibrium binding constants and aid in rational drug design, and biomolecular titration studies.

The ATLAS (Automatically Tuned Linear Algebra Software) project is an ongoing research effort focusing on applying empirical techniques in order to provide portable performance. It provides C and Fortran77 interfaces to a portably efficient BLAS implementation, as well as a few routines from LAPACK.

Babel is an IDL-based language interoperability tool specific to engineering and scientific applications. It allows Fortran 77, Fortran 90, C, C++, Java, and Python to call each other in a single address space for maximum performance. Babel won a 2006 R&D 100 award from R&D Magazine.

Written with the noweb literate programming tool, BaseEncode provides a framework for portable encoding and decoding of data in text files, somewhat similar to uuencoded arithmetic coding. By using statistical knowledge, some amount of compression can also be achieved. The algorithm is designed to be highly portable: only 16-bit signed integers are assumed. Output comes in the form of a Fortran-90 module, but translation to other languages is trivial.

The CFD General Notation System (CGNS) provides a general, portable, and extensible standard for the storage and retrieval of computational fluid dynamics (CFD) analysis data. CGNS is designed to facilitate the exchange of data between sites and applications, and to help stabilize the archiving of aerodynamic data.

CFITSIO is a library of C and Fortran subroutines for reading and writing data files in the FITS (Flexible Image Transport System) data format. It simplifies the task of writing software that deals with FITS files by providing an easy to use set of high-level routines that insulate the programmer from the internal complexities of the FITS file format.

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.

ChemApp is a programming tool from the area of computational thermochemistry. It is a library consisting of a rich set of subroutines, based on the thermodynamic phase equilibrium calculation module of ChemSage. It permits the calculation of complex, multicomponent, multiphase chemical equilibria and their associated energy balances. ChemApp is available as object code for a wide range of platforms and as a shared library/DLL. ChemApp "light" is the free version of ChemApp, and although it is restricted in two ways compared to the regular version, it gives you almost the same functionality.