Description
Energy efficiency of computing devices has become a dominant area of research interest in recent years. Most of this work is focused on architectural techniques to improve power and energy efficiency; only a few consider saving energy at the algorithmic level. We prove that a region of perfect strong scaling in energy exists for matrix multiplication (classical and Strassen) and the direct (O(n2)) n-body problem via the use of .5D algorithms: This means that we can increase the number of processors by a constant factor, with the runtime (both computation and communication) decreasing by the same factor, and the total energy used remaining constant.