Ludwig is a software package for simulation of soft matter substances, otherwise known as complex fluids. The package takes its name from Ludwig Botlzmann, since it uses the lattice Boltzmann technique as a basis for hydrodynamic simulation. However, it is also able to combine this with a range of other methods to enable the simulation of many complex fluid systems.  It is able to run on computers ranging from simple workstations to large HPC machines, including those with NVIDIA GPU or Intel Xeon Phi components.

The main developers are Kevin Stratford, Alan Gray, Oliver Henrich, Juho Lintuvuori, and Davide Marenduzzo.