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.

Hoard is a scalable memory allocator (malloc replacement) for multithreaded applications. Hoard can dramatically improve your application's performance on multicore machines. No changes to your source are necessary; just link it in. Hoard scales linearly up to at least 64 processors. Supported platforms include Linux, Solaris, Mac OS X, and Windows.

PVM (Parallel Virtual Machine) is a portable message-passing programming system, designed to link separate host machines to form a ``virtual machine'' which is a single, manageable computing resource. The virtual machine can be composed of hosts of varying types, in physically remote locations. PVM applications can be composed of any number of separate processes, or components, written in a mixture of C, C++ and Fortran. The system is portable to a wide variety of architectures, including workstations, multiprocessors, supercomputers and PCs.

PLplot is a library of C functions that are useful for making scientific plots from programs written in a wide variety of languages. It can be used to create standard x-y plots, semi-log plots, log-log plots, contour plots, 3D plots, shade (gray-scale and color) plots, mesh plots, bar charts, and pie charts. Multiple graphs may be placed on a single page with multiple lines in each graph. Different line styles, widths, and colors are supported. A virtually infinite number of distinct area fill patterns may be used. A variety of output devices and file formats are supported.

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.

xd3d is a simple scientific visualization tool designed to be easy to learn. It can plot 2D and 3D meshes, with shadowing, contour plots, vector fields, iso-contour (3D), as well as 3D surfaces z=f(x,y) defined by an algebraic expression or a cloud of points. It generates high-quality vector PostScript files for scientific publications and still or animated bitmap images. The distribution includes the graph plotter, xgraphic.

GetDP is a general finite element solver using mixed elements to discretize de Rham-type complexes in one, two, and three dimensions. The main feature of GetDP is the closeness between the input data defining discrete problems (written by the user in ASCII data files) and the symbolic mathematical expressions of these problems.