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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Multi-GPU work sharing in a task-based dataflow programming model
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Hybrid programming-model strategies for GPU offloading of electronic structure calculation kernels
To address the challenge of performance portability and facilitate the implementation of electronic structure solvers, we developed the basic matrix library (BML) and Parallel, Rapid O(N), and Graph-based Recursive Electronic Structure Solver (PROGRESS) library. The BML implements linear algebra operations necessary for electronic structure kernels using a unified user interface for various matrix formats (dense and sparse) and architectures (CPUs and GPUs). Focusing on density functional theory and tight-binding models, PROGRESS implements several solvers for computing the single-particle density matrix and relies on BML. In this paper, we describe the general strategies used for these implementations on various computer architectures, using OpenMP target functionalities on GPUs, in conjunction with third-party libraries to handle performance critical numerical kernels. In this study, we demonstrate the portability of this approach and its performance in benchmark problems.
Portable Programming Model Exploration for LArTPC Simulation in a Heterogeneous Computing Environment: OpenMP vs. SYCL
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In-Staging Data Placement for Asynchronous Coupling of Task-Based Scientific Workflows, In: 2016 Second International Workshop on Extreme Scale Programming Models and Middlewar (ESPM2)
Coupled application workflows composed of applications implemented using task-based models present new coupling and data exchange challenges, due to the asynchronous interaction and coupling behaviors between tasks of the component applications. In this paper, we present an adaptive data placement approach that addresses these challenges by dynamically adjusting to the asynchronous coupling patterns. Specifically, it places data across a set of staging cores/nodes with an awareness of the application-specific data locality requirements and the runtime task executions at these staging cores/nodes, with the goal of reducing end-to-end execution time and data movement overhead of the workflow. We experimentally demonstrate the effectiveness of our approach on the Titan Cray XK7 system using representative data coupling patterns derived from current scientific workflows. The evaluation demonstrates that our approach efficiently improves performance by reducing the time-to-solution and increasing the quality of insights for scientific discovery.
Thread-Local Concurrency: A Technique to Handle Data Race Detection at Programming Model Abstraction
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Final Project Report, DynAX Innovations in Programming Models, Compilers and Runtime Systems for Dynamic Adaptive Event Driven Execution Models
This report contains a summary of the work done for the Dynax Project from 9/1/2012 to 8/31/2015. Much of the information presented is discussed in further detail in other STI annual and quarterly reports. Additionally, a NCE report was submitted covering work done from the period of 9/1/2015 to 12/31/2015.
Towards Distributed Software Resilience in Asynchronous Many-Task Programming Models.
Abstract not provided.
Programming Model Developments Present Opportunities for Runtime and Operating Systems.
Abstract not provided.
Integrated Resilience Programming Model and Runtime: Case Study .
Abstract not provided.
Status of Apollo-Saturn 5 dynamic models program
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Aerothermal modeling program, phase 1
The combustor performance submodels for complex flows are evaluated. The benchmark test cases for complex nonswirling flows are identified and analyzed. The introduction of swirl into the flow creates much faster mixing, caused by radial pressure gradients and increase in turbulence generation. These phenomena are more difficult to predict than the effects due to geometrical streamline curvatures, like the curved duct, and sudden expansion. Flow fields with swirl, both confined and unconfined are studied. The role of the dilution zone to achieve the turbine inlet radial profile plays an important part, therefore temperature field measurements were made in several idealized dilution zone configurations.
Improved numerical methods for turbulent viscous flows aerothermal modeling program, phase 2
The details of a study to develop accurate and efficient numerical schemes to predict complex flows are described. In this program, several discretization schemes were evaluated using simple test cases. This assessment led to the selection of three schemes for an in-depth evaluation based on two-dimensional flows. The scheme with the superior overall performance was incorporated in a computer program for three-dimensional flows. To improve the computational efficiency, the selected discretization scheme was combined with a direct solution approach in which the fluid flow equations are solved simultaneously rather than sequentially.
Aerothermal modeling program. Phase 2, element A: Improved numerical methods for turbulent viscous recirculating flows
The objective of this effort is to develop improved numerical schemes for predicting combustor flow fields. Various candidate numerical schemes were evaluated, and promising schemes were selected for detailed assessment. The criteria for evaluation included accuracy, computational efficiency, stability, and ease of extension to multidimensions. The candidate schemes were assessed against a variety of simple one- and two-dimensional problems. These results led to the selection of the following schemes for further evaluation: flux spline schemes (linear and cubic) and controlled numerical diffusion with internal feedback (CONDIF). The incorporation of the flux spline scheme and direct solution strategy in a computer program for three-dimensional flows is in progress.
Program Models Propagation Of Failures
FIRM is software tool for identification of failure and management of risk based on directed-graph ("digraph") approach. Three core algorithms optimized for processing singletons and doubletons and also handle tripletons. FIRM identifies loops in digraphs and displays direct failure paths between any two nodes. Solves for reachability for given node without computing reachability for entire digraph. Represents hybrid between schematic-diagram and fault-tree approaches. Written in C.
GEWEX Modeling Program
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Programs Model the Future of Air Traffic Management
Through Small Business Innovation Research (SBIR) contracts with Ames Research Center, Intelligent Automation Inc., based in Rockville, Maryland, advanced specialized software the company had begun developing with U.S. Department of Defense funding. The agent-based infrastructure now allows NASA's Airspace Concept Evaluation System to explore ways of improving the utilization of the National Airspace System (NAS), providing flexible modeling of every part of the NAS down to individual planes, airports, control centers, and even weather. The software has been licensed to a number of aerospace and robotics customers, and has even been used to model the behavior of crowds.