Nathan Wichmann

Learn More
The Gemini interconnect on the Cray XE6 platform provides for lightweight remote direct memory access (RDMA) between nodes, which is useful for implementing partitioned global address space languages like UPC and Co-Array Fortran. In this paper, we perform a study of Gemini performance using a set of communication microbenchmarks and compare the performance(More)
In this paper we explore new parallel language constructs for the communication kernel of a real world magnetic fusion simulation code using the Partitioned Global Address Space (PGAS) model. The studied kernel is the particle shift phase of a tokamak simulation code in a toroidal geometry, which models the transit of charged particles between neighboring(More)
We present novel parallel language constructs for the communication intensive part of a magnetic fusion simulation code. The focus of this work is the shift phase of charged particles of a tokamak simulation code in toroidal geometry. We introduce new hybrid PGAS/OpenMP implementations of highly optimized hybrid MPI/OpenMP based communication kernels. The(More)
We develop a method for improving the parallel scalability of the recently developed parallel selected inversion algorithm [Jacquelin, Lin and Yang 2014], named PSelInv, on massively parallel distributed memory machines. In the PSelInv method, we compute selected elements of the inverse of a sparse matrix A that can be decomposed as A = LU , where L is(More)
  • 1