In the mid-eighties Paul Fischer, Lee Ho, and Einar Ronquist (M.I.T) developed the incompressible fluid flow solver NEKTON, with technical input from A. Patera and Y. Maday. A commercial version was brought to market by Fluent, Inc, as NEKTON 2.0, in 1996. Paul Fischer branched off a research version of the code known as Nek5000. This code was recognized with the Gordon Bell prize for algorithmic quality and sustained parallel performance in 1999. Today, Fischer’s code is released as an open source project covering a broad range of applications including thermal hydraulics of reactor cores, transition in vascular flows, ocean current modeling and combustion (see gallery). More than two dozen institutions and more than 200 users worldwide are using the code (see users). Leading edge scalability has been demonstrated up to 262’144 processors producing more than 170TFlops. link


Nek5000 is released under the terms of the GNU GPL license. It can be freely downloaded, installed, used and modified. The source code is provided through the project’s subversion repository.

Supported Platforms

Nek5000 has been run on numerous platforms from Mac laptops, to Cray supercomputers, to the IBM Blue Gene Machines. Since Nek5000 is mostly an independent, stand-alone code, most platforms prividing a Fortran 77 and a C compiler are compatible with the code. Specialized compilers may require some adaptations. See below for a list of known and tested compilers.

Nek5000 builds on many Unix-like operating systems by generating a Makefile through using the makenek bash script (shipped with the source code). Setting system specific parameters is done in makenek.

Nek5000 conforms to the ANSI standards for Fortran 77 and C including the extensions from MIL-STD-1753 and is compatible with
MPI standard v.1.1 and above.

Currently supported and tested compilers: