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MultiSource/Benchmarks/DOE-ProxyApps-C++/HACCKernels/README
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| CCKernels: A Benchmark for HACC's Particle Force Kernels | |||||
| The Hardware/Hybrid Accelerated Cosmology Code (HACC), a cosmology N-body-code | |||||
| framework, is designed to run efficiently on diverse computing architectures | |||||
| and to scale to millions of cores and beyond. The gravitational force is the | |||||
| only significant force between particles at cosmological scales, and, in HACC, | |||||
| this force is divided into two components: a long-range component and a | |||||
| short-range component. The long-range component is handled using a distributed | |||||
| grid-based solver, and the short-range component is by more-direct | |||||
| particle-particle computations. On many systems, a tree-based multipole | |||||
| approximation is used to further reduce the computational complexity of the | |||||
| short-range force. The inner-most computation is a direct N^2 particle-particle | |||||
| force calculation of the short-range part of the gravitational force. It is this | |||||
| inner-most calculation that consumes most of the simulation time, is | |||||
| computationally bound, and is what is represented by this benchmark. | |||||
| Because this inner-most force calculation is algorithmically isolated from the | |||||
| overall scale of the problem, the parameters don't need to be adjusted to | |||||
| represent the workload on different machine scales (e.g. petascale or | |||||
| exascale). | |||||
| For more information on HACC, see: | |||||
| Salman Habib, et al. HACC: Simulating Sky Surveys on State-of-the-Art | |||||
| Supercomputing Architectures. New Astronomy Volume 42, January 2016, pp. 49-65. | |||||
| http://doi.org/10.1016/j.newast.2015.06.003 | |||||
| https://arxiv.org/abs/1410.2805 | |||||
| The benchmark can be compiled using cmake (or make directly using | |||||
| Makefile.simple) and then run like this: | |||||
| $ ./HACCKernels | |||||
| Maximum OpenMP Threads: 1 | |||||
| Iterations: 2000 | |||||
| Gravity Short-Range-Force Kernel (4th Order): 26307.2 -122.385 -1369.32: 4.45269 s | |||||
| Gravity Short-Range-Force Kernel (5th Order): 26297.5 -123.056 -1368.67: 4.51347 s | |||||
| Gravity Short-Range-Force Kernel (6th Order): 26297.6 -123.225 -1368.66: 4.8256 s | |||||
| The accumulated acceleration in each direction for all particles in the last | |||||
| iteration, which is a function of the total number of iterations, is printed as | |||||
| a diagnostic. It should be similar for all polynomial kernel orders. | |||||
| If you'd like the benchmark only to display deterministic output (i.e. | |||||
| omitting information on the number of threads, timing, and the like), then | |||||
| define the preprocessor symbol VERIFICATION_OUTPUT_ONLY when compiling. | |||||
| You can enable this option when configuring by passing | |||||
| -DVERIFICATION_OUTPUT_ONLY=ON to cmake. | |||||
| Compared to the older HACCmk procurement benchmark | |||||
| (https://asc.llnl.gov/CORAL-benchmarks/#haccmk), this benchmark: | |||||
| * More closely matches the parallelization scheme used by the production code. | |||||
| * Uses a more-realistic distribution of interaction-list lengths and | |||||
| out-of-bounds particles. | |||||
| * Includes 4th-, 5th-, and 6th-order kernels. | |||||
| For more information, contact: Hal Finkel <hfinkel@anl.gov> | |||||