A Multi-Scale Heart Simulation on Massively Parallel Computers

To understand the macroscopic function of the human heart based on sub-cellular microscopic events, multiscale analysis is indispensable. Our heart simulator uses the so-called homogenization method, where both the human heart and the myocardial cells are modeled and solved simultaneously by the finite element method. Because the contraction and deformation of each finite element in the heart model are governed by their respective cell model, the NDOF of all the cells becomes prohibitively large. Furthermore, the phenomena are highly nonlinear and transient. This challenging problem has been tackled by our group for many years, and a novel algorithm to accelerate the computation was implemented in the code. We have recently tested its performance using the T2K Open Supercomputer (Tokyo). A pulsation of the heart with a total NDOF of 160 million was successfully simulated using 6144 CPU cores in ten hours. Scalability and other computational performances were measured and are discussed.