  We present an easy to use and flexible grid library for developing highly
scalable parallel simulations. The distributed cartesian cell-refinable grid
(dccrg) supports adaptive mesh refinement and allows an arbitrary C++ class to
be used as cell data. The amount of data in grid cells can vary both in space
and time allowing dccrg to be used in very different types of simulations, for
example in fluid and particle codes. Dccrg transfers the data between
neighboring cells on different processes transparently and asynchronously
allowing one to overlap computation and communication. This enables excellent
scalability at least up to 32 k cores in magnetohydrodynamic tests depending on
the problem and hardware. In the version of dccrg presented here part of the
mesh metadata is replicated between MPI processes reducing the scalability of
adaptive mesh refinement (AMR) to between 200 and 600 processes. Dccrg is free
software that anyone can use, study and modify and is available at
[https://gitorious.org/dccrg]. Users are also kindly requested to cite this
work when publishing results obtained with dccrg.
