Lattice QCD with Domain Decomposition on Intel Xeon Phi Co-Processors

The gap between the cost of moving data and the cost of computing continues to grow, making it ever harder to design iterative solvers on extreme-scale architectures. This problem can be alleviated by alternative algorithms that reduce the amount of data movement. We investigate this in the context of Lattice Quantum Chromodynamics and implement such an alternative solver algorithm, based on domain decomposition, on Intel Xeon Phi co-processor (KNC) clusters. We demonstrate close-to-linear on-chip scaling to all 60 cores of the KNC. With a mix of single- and half-precision the domain-decomposition method sustains 400-500 Gflop/s per chip. Compared to an optimized KNC implementation of a standard solver [1], our full multi-node domain-decomposition solver strong-scales to more nodes and reduces the time-to-solution by a factor of 5.Comment: 12 pages, 7 figures, presented at Supercomputing 2014, November 16-21, 2014, New Orleans, Louisiana, USA, speaker Simon Heybrock; SC '14 Proceedings of the International Conference for High Performance Computing, Networking, Storage and Analysis, pages 69-80, IEEE Press Piscataway, NJ, USA (c)201

Development of parallel meshless methods for moving geometry simulations

Computational uid dynamics methods to simulate ows around geometries in relative motion are important for the aerospace industry. Traditional methods like �nite-volume techniques are better suited for static simulations where the geometry of the problem does not change, or where only small movements are found. The meshless method can provide a solution for these problems where the geometry changes signi�cantly and di�erent bodies can move in relation to one another. A meshless method to select stencils from overlapping and moving point distributions, and a corresponding ow solver capable of solving the Euler equations on those stencils, have been developed previously. This work expands the existing meshless formulation by including the capabilities to simulate viscous ows in laminar and turbulent regimes and by implementing di�erent parallel computing techniques in an e�ort to improve the computational e�ciency. The treatment of viscous and turbulent ows is performed by augmenting the original Euler meshless scheme by using central-di�erences to discretise the viscous terms in the Navier-Stokes equations. The Spalart-Allmaras turbulence model is used to model the turbulent viscosity term and complete the closure of the system of equations to be solved. Validation of the method was carried out by calculating several well-known test cases and comparing the results to published data. The parallel implementation of the ow solver follows a distributed approach with asynchronous communications using message-passing standards. The parallel ow solver method is tested with two three-dimensional geometries, running in dedicated parallel machines with processor numbers ranging in the thousands. Results show good agreement to published data and very good parallel scalability. Preliminary testing of the stencil selection method, showed that the computational cost of the operations needed to �nd stencils for each point in the domain can vary dramatically for all points. Furthermore, this cost cannot be predicted a-priori, making it very di�cult to perform an appropriate domain decomposition. With this in mind, three types of implementation are used for the parallel stencil selection scheme: a distributed memory approach, a shared memory approach and hybrid method combining the two previous ones. Using the shared and hybrid implementations, the negative e�ects of using a poor domain decomposition are reduced. Four test cases are studied using the parallel stencil selection procedure coupled with the parallel ow solver. Two of these cases are static, and two of them are simulations over moving geometries. The fourth case introduces a 6 degree-of-freedom simulation to calculate the movement of a store being released from an aircraft and showcases the full capabilities of the method. These parallel tests show important reductions in the calculation times and open the door for the meshless scheme to be used in the future for more realistic cases

The Sixth Copper Mountain Conference on Multigrid Methods, part 1

The Sixth Copper Mountain Conference on Multigrid Methods was held on 4-9 Apr. 1993, at Copper Mountain, CO. This book is a collection of many of the papers presented at the conference and as such represents the conference proceedings. NASA LaRC graciously provided printing of this document so that all of the papers could be presented in a single forum. Each paper was reviewed by a member of the conference organizing committee under the coordination of the editors. The multigrid discipline continues to expand and mature, as is evident from these proceedings. The vibrancy in this field is amply expressed in these important papers, and the collection clearly shows its rapid trend to further diversity and depth

FUN3D Manual: 12.8

This manual describes the installation and execution of FUN3D version 12.8, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status

FUN3D Manual: 12.9

This manual describes the installation and execution of FUN3D version 12.9, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status

FUN3D Manual: 12.7

This manual describes the installation and execution of FUN3D version 12.7, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status

FUN3D Manual: 13.2

This manual describes the installation and execution of FUN3D version 13.2, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status