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Formulas for robust, one-pass parallel computation of covariances and arbitrary-order statistical moments.

Description: We present a formula for the pairwise update of arbitrary-order centered statistical moments. This formula is of particular interest to compute such moments in parallel for large-scale, distributed data sets. As a corollary, we indicate a specialization of this formula for incremental updates, of particular interest to streaming implementations. Finally, we provide pairwise and incremental update formulas for the covariance. Centered statistical moments are one of the most widely used tools in … more
Date: September 1, 2008
Creator: Pebay, Philippe Pierre
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Scalable descriptive and correlative statistics with Titan.

Description: This report summarizes the existing statistical engines in VTK/Titan and presents the parallel versions thereof which have already been implemented. The ease of use of these parallel engines is illustrated by the means of C++ code snippets. Furthermore, this report justifies the design of these engines with parallel scalability in mind; then, this theoretical property is verified with test runs that demonstrate optimal parallel speed-up with up to 200 processors.
Date: December 1, 2008
Creator: Thompson, David C. & Pebay, Philippe Pierre
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Parallel tetrahedral mesh refinement with MOAB.

Description: In this report, we present the novel functionality of parallel tetrahedral mesh refinement which we have implemented in MOAB. This report details work done to implement parallel, edge-based, tetrahedral refinement into MOAB. The theoretical basis for this work is contained in [PT04, PT05, TP06] while information on design, performance, and operation specific to MOAB are contained herein. As MOAB is intended mainly for use in pre-processing and simulation (as opposed to the post-processing bent … more
Date: December 1, 2008
Creator: Thompson, David C. & Pebay, Philippe Pierre
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Current parallel I/O limitations to scalable data analysis.

Description: This report describes the limitations to parallel scalability which we have encountered when applying our otherwise optimally scalable parallel statistical analysis tool kit to large data sets distributed across the parallel file system of the current premier DOE computational facility. This report describes our study to evaluate the effect of parallel I/O on the overall scalability of a parallel data analysis pipeline using our scalable parallel statistics tool kit [PTBM11]. In this goal, we t… more
Date: July 1, 2011
Creator: Mascarenhas, Ajith Arthur & Pebay, Philippe Pierre
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Parallel contingency statistics with Titan.

Description: This report summarizes existing statistical engines in VTK/Titan and presents the recently parallelized contingency statistics engine. It is a sequel to [PT08] and [BPRT09] which studied the parallel descriptive, correlative, multi-correlative, and principal component analysis engines. The ease of use of this new parallel engines is illustrated by the means of C++ code snippets. Furthermore, this report justifies the design of these engines with parallel scalability in mind; however, the very n… more
Date: September 1, 2009
Creator: Thompson, David C. & Pebay, Philippe Pierre
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Performance of a streaming mesh refinement algorithm.

Description: In SAND report 2004-1617, we outline a method for edge-based tetrahedral subdivision that does not rely on saving state or communication to produce compatible tetrahedralizations. This report analyzes the performance of the technique by characterizing (a) mesh quality, (b) execution time, and (c) traits of the algorithm that could affect quality or execution time differently for different meshes. It also details the method used to debug the several hundred subdivision templates that the algorit… more
Date: August 1, 2004
Creator: Thompson, David C. & Pebay, Philippe Pierre
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Parallel auto-correlative statistics with VTK.

Description: This report summarizes existing statistical engines in VTK and presents both the serial and parallel auto-correlative statistics engines. It is a sequel to [PT08, BPRT09b, PT09, BPT09, PT10] which studied the parallel descriptive, correlative, multi-correlative, principal component analysis, contingency, k-means, and order statistics engines. The ease of use of the new parallel auto-correlative statistics engine is illustrated by the means of C++ code snippets and algorithm verification is prov… more
Date: August 1, 2013
Creator: Pebay, Philippe Pierre & Bennett, Janine Camille
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

An Exodus II specification for handling gauss points.

Description: This report specifies the way in which Gauss points shall be named and ordered when storing them in an EXODUS II file so that they may be properly interpreted by visualization tools. This naming convention covers hexahedra and tetrahedra. Future revisions of this document will cover quadrilaterals, triangles, and shell elements.
Date: November 1, 2007
Creator: Thompson, David C.; Jortner, Jeffrey N. & Pebay, Philippe Pierre
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Scalable k-means statistics with Titan.

Description: This report summarizes existing statistical engines in VTK/Titan and presents both the serial and parallel k-means statistics engines. It is a sequel to [PT08], [BPRT09], and [PT09] which studied the parallel descriptive, correlative, multi-correlative, principal component analysis, and contingency engines. The ease of use of the new parallel k-means engine is illustrated by the means of C++ code snippets and algorithm verification is provided. This report justifies the design of the statistics… more
Date: November 1, 2009
Creator: Thompson, David C.; Bennett, Janine C. & Pebay, Philippe Pierre
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Computational algebraic geometry for statistical modeling FY09Q2 progress.

Description: This is a progress report on polynomial system solving for statistical modeling. This is a progress report on polynomial system solving for statistical modeling. This quarter we have developed our first model of shock response data and an algorithm for identifying the chamber cone containing a polynomial system in n variables with n+k terms within polynomial time - a significant improvement over previous algorithms, all having exponential worst-case complexity. We have implemented and verified … more
Date: March 1, 2009
Creator: Thompson, David C.; Rojas, Joseph Maurice & Pebay, Philippe Pierre
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A data storage model for novel partial differential equation descretizations.

Description: The purpose of this report is to define a standard interface for storing and retrieving novel, non-traditional partial differential equation (PDE) discretizations. Although it focuses specifically on finite elements where state is associated with edges and faces of volumetric elements rather than nodes and the elements themselves (as implemented in ALEGRA), the proposed interface should be general enough to accommodate most discretizations, including hp-adaptive finite elements and even mimetic… more
Date: April 1, 2007
Creator: Doyle, Wendy S.K.; Thompson, David C. & Pebay, Philippe Pierre
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Determining the Bayesian optimal sampling strategy in a hierarchical system.

Description: Consider a classic hierarchy tree as a basic model of a 'system-of-systems' network, where each node represents a component system (which may itself consist of a set of sub-systems). For this general composite system, we present a technique for computing the optimal testing strategy, which is based on Bayesian decision analysis. In previous work, we developed a Bayesian approach for computing the distribution of the reliability of a system-of-systems structure that uses test data and prior info… more
Date: September 1, 2010
Creator: Grace, Matthew D.; Ringland, James T.; Boggs, Paul T. & Pebay, Philippe Pierre
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Meaningful statistical analysis of large computational clusters.

Description: Effective monitoring of large computational clusters demands the analysis of a vast amount of raw data from a large number of machines. The fundamental interactions of the system are not, however, well-defined, making it difficult to draw meaningful conclusions from this data, even if one were able to efficiently handle and process it. In this paper we show that computational clusters, because they are comprised of a large number of identical machines, behave in a statistically meaningful fashi… more
Date: July 1, 2005
Creator: Gentile, Ann C.; Marzouk, Youssef M.; Brandt, James M. & Pebay, Philippe Pierre
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Monitoring computational clusters with OVIS.

Description: Traditional cluster monitoring approaches consider nodes in singleton, using manufacturer-specified extreme limits as thresholds for failure ''prediction''. We have developed a tool, OVIS, for monitoring and analysis of large computational platforms which, instead, uses a statistical approach to characterize single device behaviors from those of a large number of statistically similar devices. Baseline capabilities of OVIS include the visual display of deterministic information about state vari… more
Date: December 1, 2006
Creator: Gentile, Ann C.; Brandt, James M.; Wong, M. H. & Pebay, Philippe Pierre
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Scalable multi-correlative statistics and principal component analysis with Titan.

Description: This report summarizes existing statistical engines in VTK/Titan and presents the recently parallelized multi-correlative and principal component analysis engines. It is a sequel to [PT08] which studied the parallel descriptive and correlative engines. The ease of use of these parallel engines is illustrated by the means of C++ code snippets. Furthermore, this report justifies the design of these engines with parallel scalability in mind; then, this theoretical property is verified with test ru… more
Date: February 1, 2009
Creator: Thompson, David C.; Bennett, Janine C.; Roe, Diana C. & Pebay, Philippe Pierre
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Visualization of higher order finite elements.

Description: Finite element meshes are used to approximate the solution to some differential equation when no exact solution exists. A finite element mesh consists of many small (but finite, not infinitesimal or differential) regions of space that partition the problem domain, {Omega}. Each region, or element, or cell has an associated polynomial map, {Phi}, that converts the coordinates of any point, x = ( x y z ), in the element into another value, f(x), that is an approximate solution to the differential… more
Date: April 1, 2004
Creator: Thompson, David C.; Pebay, Philippe Pierre; Crawford, Richard H. & Khardekar, Rahul Vinay
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A half-explicit, non-split projection method for low Mach number flows.

Description: In the context of the direct numerical simulation of low MACH number reacting flows, the aim of this article is to propose a new approach based on the integration of the original differential algebraic (DAE) system of governing equations, without further differentiation. In order to do so, while preserving a possibility of easy parallelization, it is proposed to use a one-step index 2 DAE time-integrator, the Half Explicit Method (HEM). In this context, we recall why the low MACH number approxi… more
Date: February 1, 2004
Creator: Pousin, Jerome G. (National Institute for Applied Sciences, France); Najm, Habib N. & Pebay, Philippe Pierre
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

OVIS 2.0 user%3CU%2B2019%3Es guide.

Description: This document describes how to obtain, install, use, and enjoy a better life with OVIS version 2.0. The OVIS project targets scalable, real-time analysis of very large data sets. We characterize the behaviors of elements and aggregations of elements (e.g., across space and time) in data sets in order to detect anomalous behaviors. We are particularly interested in determining anomalous behaviors that can be used as advance indicators of significant events of which notification can be made or up… more
Date: April 1, 2009
Creator: Mayo, Jackson R.; Gentile, Ann C.; Brandt, James M.; Thompson, David C.; Roe, Diana C.; Wong, Matthew H. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

OVIS 3.2 user's guide.

Description: This document describes how to obtain, install, use, and enjoy a better life with OVIS version 3.2. The OVIS project targets scalable, real-time analysis of very large data sets. We characterize the behaviors of elements and aggregations of elements (e.g., across space and time) in data sets in order to detect meaningful conditions and anomalous behaviors. We are particularly interested in determining anomalous behaviors that can be used as advance indicators of significant events of which noti… more
Date: October 1, 2010
Creator: Mayo, Jackson R.; Gentile, Ann C.; Brandt, James M.; Houf, Catherine A.; Thompson, David C.; Roe, Diana C. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

The OVIS analysis architecture.

Description: This report summarizes the current statistical analysis capability of OVIS and how it works in conjunction with the OVIS data readers and interpolators. It also documents how to extend these capabilities. OVIS is a tool for parallel statistical analysis of sensor data to improve system reliability. Parallelism is achieved using a distributed data model: many sensors on similar components (metaphorically sheep) insert measurements into a series of databases on computers reserved for analyzing th… more
Date: July 1, 2010
Creator: Mayo, Jackson R.; Gentile, Ann C.; Brandt, James M.; De Sapio, Vincent; Thompson, David C.; Roe, Diana C. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A variational solution to the transport equation subject to an affine constraint.

Description: We establish an existence and uniqueness theorem for the transport equation subject to an inequality affine constraint, viewed as a constrained optimization problem. Then we derive a Space-Time Integrated Least Squares (STILS) scheme for its numerical approximation. Furthermore, we discuss some L{sup 2}-projection strategies and with numerical examples we show that there are not relevant for that problem.
Date: February 1, 2004
Creator: Pousin, Jerome G. (National Institute of Applied Sciences, Villeurbanne Cedex, France); Najm, Habib N.; Picq, Martine (National Institute of Applied Sciences, Villeurbanne Cedex, France) & Pebay, Philippe Pierre
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A framework for graph-based synthesis, analysis, and visualization of HPC cluster job data.

Description: The monitoring and system analysis of high performance computing (HPC) clusters is of increasing importance to the HPC community. Analysis of HPC job data can be used to characterize system usage and diagnose and examine failure modes and their effects. This analysis is not straightforward, however, due to the complex relationships that exist between jobs. These relationships are based on a number of factors, including shared compute nodes between jobs, proximity of jobs in time, etc. Graph-bas… more
Date: August 1, 2010
Creator: Mayo, Jackson R.; Kegelmeyer, W. Philip, Jr.; Wong, Matthew H.; Pebay, Philippe Pierre; Gentile, Ann C.; Thompson, David C. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Bayesian methods for estimating the reliability in complex hierarchical networks (interim report).

Description: Current work on the Integrated Stockpile Evaluation (ISE) project is evidence of Sandia's commitment to maintaining the integrity of the nuclear weapons stockpile. In this report, we undertake a key element in that process: development of an analytical framework for determining the reliability of the stockpile in a realistic environment of time-variance, inherent uncertainty, and sparse available information. This framework is probabilistic in nature and is founded on a novel combination of cla… more
Date: May 1, 2007
Creator: Marzouk, Youssef M.; Zurn, Rena M.; Boggs, Paul T.; Diegert, Kathleen V. (Sandia National Laboratories, Albuquerque, NM); Red-Horse, John Robert (Sandia National Laboratories, Albuquerque, NM) & Pebay, Philippe Pierre
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

The verdict geometric quality library.

Description: Verdict is a collection of subroutines for evaluating the geometric qualities of triangles, quadrilaterals, tetrahedra, and hexahedra using a variety of metrics. A metric is a real number assigned to one of these shapes depending on its particular vertex coordinates. These metrics are used to evaluate the input to finite element, finite volume, boundary element, and other types of solvers that approximate the solution to partial differential equations defined over regions of space. The geometri… more
Date: March 1, 2006
Creator: Knupp, Patrick Michael; Ernst, C.D. (Elemental Technologies, Inc., American Fork, UT); Thompson, David C. (Sandia National Laboratories, Livermore, CA); Stimpson, C.J. (Elemental Technologies, Inc., American Fork, UT) & Pebay, Philippe Pierre
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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