In ab-initio Configuration Interaction calculations, the nuclear wavefunction is expanded in Slater determinants of single-nucleon wavefunctions and the many-body Schrodinger equation becomes a large sparse matrix pro...
In ab-initio Configuration Interaction calculations, the nuclear wavefunction is expanded in Slater determinants of single-nucleon wavefunctions and the many-body Schrodinger equation becomes a large sparse matrix problem. The challenge is to reach numerical convergence to within quantified numerical uncertainties for physical observables using finite truncations of the infinite-dimensional basis space. We discuss strategies for constructing and solving the resulting large sparse matrix eigenvalue problems on current multicore computer architectures. Several of these strategies have been implemented in the code MFDn, a hybrid MPI/OpenMP Fortran code for ab-initio nuclear structure calculations that can scale to 100,000 cores and more. Finally, we will conclude with some recent results for 12C including emerging collective phenomena such as rotational band structures using SRG evolved chiral N3LO interactions.
Surgeons on a daily basis improve or rescue human lives. Therefore, they should be provided with the most optimal tools so their skills are fully utilized. In this paper, we present such an optimized tool for surgeons...
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Surgeons on a daily basis improve or rescue human lives. Therefore, they should be provided with the most optimal tools so their skills are fully utilized. In this paper, we present such an optimized tool for surgeons who employ the Nuss procedure to correct pectus excavatum - a congenital chest wall deformity. The Nuss procedure is a minimally invasive procedure that results in the placement of a metal bar inside the chest cavity. The bar is removed after approximately two years. Surgeons have been reporting that the currently available tools for the bar extraction do not provide the most optimal functionality. Therefore, we have proposed an optimized and improved design of the tool for the bar extraction. The improved design tool is further analyzed using finite element techniques. Additionally, we have built a physical prototype to ensure that the new tool to seamlessly integrate with the bar and to further evaluate by the surgeons who routinely practice the Nuss procedure. In order to validate in the future the final design, we have manufactured wax models that will serve as the patterns in the casting process of metal prototypes. They should provide enough strength to withstand stresses present in the bar straightening process.
Detailed tree information, such as tree counts, tree heights, crown base heights, diameter at breast height (DBH), and tree biomass, is critical for the effective management and quantitative analysis of trees in urban...
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Detailed tree information, such as tree counts, tree heights, crown base heights, diameter at breast height (DBH), and tree biomass, is critical for the effective management and quantitative analysis of trees in urban area. Automatic detection of trees, and their parameters using light detection and ranging (LiDAR) data has been widely employed. However, at the single-tree level along road in urban area, LiDAR data deposed the disadvantages such as space points, no texture information, so that the detailed tree parameters mentioned above cannot successfully be obtain at enough accuracy. This paper presented an integration of LiDAR data and ground mobile truck data. This development is driven by the fact that the information obtained from ground-mobile truck images can be substantially complemented by the data from LiDAR.
SCIRun is a general purpose problem solving environment that seeks to integrate the steps of preparing, executing, and visualizing simulations of physical and biological systems. The implementation of SCIRun is by mea...
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SCIRun is a general purpose problem solving environment that seeks to integrate the steps of preparing, executing, and visualizing simulations of physical and biological systems. The implementation of SCIRun is by means of an interactive dataflow network consisting of modules and data pipes exposed as a visual programming language. SCIRun also contains specific modules for bioelectric field simulations and visualizations and the combination of SCIRun with this package is known as BioPSE (***/software/biopse). This software has been in the public domain since 2000 and in that time we have developed strategies for software development, engineering, testing, documentation, and training. We have also continued to expand the scope of the SCIRun/BioPSE package not only through our own codes but by constructing bridges to other systems, both open source and proprietary. We have also created a repository for relevant sample networks and datasets with the aim of allowing diverse groups to test and evaluate algorithms using identical data and to share their results with the community for comparison of performance and accuracy. We present here a summary of the software system and describe specific experiences and conclusions with regard to creating and managing a large open source software project carried out within a university setting.
Scalability of a low-cost, Intel Xeon-based, multi-Teraflop Linux cluster is tested for two high-end scientific applications: Classical atomistic simulation based on the molecular dynamics method and quantum mechanica...
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Scalability of a low-cost, Intel Xeon-based, multi-Teraflop Linux cluster is tested for two high-end scientific applications: Classical atomistic simulation based on the molecular dynamics method and quantum mechanica...
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Scalability of a low-cost, Intel Xeon-based, multi-Teraflop Linux cluster is tested for two high-end scientific applications: Classical atomistic simulation based on the molecular dynamics method and quantum mechanical calculation based on the density functional theory. These scalable parallel applications use spacetime multiresolution algorithms and feature computational-space decomposition, wavelet-based adaptive load balancing, and spacefilling-curve-based data compression for scalable I/O. Comparative performance tests are performed on a 1024-processor Linux cluster and a conventional higher-end parallel supercomputer, 1184-processor IBM SP4. The results show that the performance of the Linux cluster is comparable to that of the SP4. We also study various effects, such as the sharing of memory and L2 cache among processors, on the performance.
A suite of scalable atomistic simulation programs has been developed for materials research based on space-time multiresolution algorithms. Design and analysis of parallel algorithms are presented for molecular dynami...
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A suite of scalable atomistic simulation programs has been developed for materials research based on space-time multiresolution algorithms. Design and analysis of parallel algorithms are presented for molecular dynamics (MD) simulations and quantum-mechanical (QM) calculations based on the density functional theory. Performance tests have been carried out on 1,088-processor Cray T3E and 1,280-processor IBM SP3 computers. The linear-scaling algorithms have enabled 6.44-billion-atom MD and 111,000-atom QM calculations on 1,024 SP3 processors with parallel efficiency well over 90%. The production-quality programs also feature wavelet-based computational-space decomposition for adaptive load balancing, spacefilling-curve-based adaptive data compression with user-defined error bound for scalable I/O, and octree-based fast visibility culling for immersive and interactive visualization of massive simulation data.
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