  We present HTMPC, a Heavily Templated C++ library for large-scale simulations
implementing multi-particle collision dynamics (MPC), a particle-based
mesoscale hydrodynamic simulation method. The implementation is plugin-based,
and designed for distributed computing over an arbitrary number of MPI ranks.
By abstracting the hardware-dependent parts of the implementation, we provide
an identical application-code base for various architectures, currently
supporting CPUs and CUDA-capable GPUs. We have examined the code for a system
of more than a trillion MPC particles distributed over a few thousand MPI ranks
(GPUs), demonstrating the scalability of the implementation and its
applicability to large-scale hydrodynamic simulations. As showcases, we examine
passive and active suspension of colloids, which confirms the extensibility and
versatility of our plugin-based implementation.
