The Chroma software system for lattice QCD

We describe aspects of the Chroma software system for lattice QCD calculations. Chroma is an open source C++ based software system developed using the software infrastructure of the US SciDAC initiative. Chroma interfaces with output from the BAGEL assembly generator for optimised lattice fermion kernels on some architectures. It can be run on workstations, clusters and the QCDOC supercomputer.