ExaStencils: Advanced stencil-code engineering

Abstract. Project ExaStencils pursues a radically new approach to stencil-code engineering. Present-day stencil codes are implemented in general-purpose programming languages, such as Fortran, C, or Java, or derivates thereof, and harnesses for parallelism, such as OpenMP, OpenCL or MPI. ExaStencils favors a much more domain-specific ap-being the mathematical formulation, the most concrete the optimized target code. At every layer, the corresponding language expresses not only computational directives but also domain knowledge of the problem and platform to be leveraged for optimization. This approach will enable a highly automated code generation at all layers and has been demon-strated successfully before in the U.S. projects FFTW and SPIRAL for certain linear transforms. 1 The Challenges of Exascale Computing The performance of supercomputers is on the way from petascale to exascale