177,587 research outputs found
Differentiation Theory over Infinite-Dimensional Banach Spaces
No full textIn this paper we study, for any positive integer and for any subset\ \ of \QTR{bf}{N}^{\ast }, the Banach space of the bounded real sequences , and a measure over \left( \QTR{bf}{R}^{I},\QTR{cal}{B}^{(I)}\right) that generalizes the -dimensional Lebesgue one. Moreover, we expose a differentiation theory for the functions defined over this space. The main result of our paper is a change of variables' formula for the integration of the measurable real functions on \left( \QTR{bf}{R}^{I},\QTR{cal}{B}^{(I)}\right) . This change of variables is defined by some infinite-dimensional functions with properties that generalize the analogous ones of the standard finite-dimensional diffeomorphisms
Change of variables' formula for the integration of the measurable real functions over infinite-dimensional Banach spaces
No full textIn this paper we study, for any subset of and for
any strictly positive integer , the Banach space of the bounded
real sequences , and a measure over
that generalizes the
-dimensional Lebesgue one. Moreover, we recall the main results about the
differentiation theory over . The main result of our paper is a change
of variables' formula for the integration of the measurable real functions on
. This change of variables
is defined by some functions over an open subset of , with values on
, called -general, with properties that
generalize the analogous ones of the finite-dimensional diffeomorphisms
Infinite-dimensional Gaussian change of variables’ formula
No full textIn this paper, we study the Banach space ∞ of the bounded real sequences, and a
measure N(a, ) over (R∞
, B∞
) analogous to the finite-dimensional Gaussian law.
The main result of our paper is a change of variables’ formula for the integration,
with respect to N(a, ), of the measurable real functions on (E∞, B∞
(E∞)), where
E∞ is the separable Banach space of the convergent real sequences. This change of
variables is given by some (m, σ) functions, defined over a subset of E∞, with values
on E∞, with properties that generalize the analogous ones of the finite-dimensional
diffeomorphisms
Asymptotic behaviour of a BIPF algorithm with an improper target
No full textsummary:The BIPF algorithm is a Markovian algorithm with the purpose of simulating certain probability distributions supported by contingency tables belonging to hierarchical log-linear models. The updating steps of the algorithm depend only on the required expected marginal tables over the maximal terms of the hierarchical model. Usually these tables are marginals of a positive joint table, in which case it is well known that the algorithm is a blocking Gibbs Sampler. But the algorithm makes sense even when these marginals do not come from a joint table. In this case the target distribution of the algorithm is necessarily improper. In this paper we investigate the simplest non trivial case, i. e. the hierarchical interaction. Our result is that the algorithm is asymptotically attracted by a limit cycle in law
A note on the IPF algorithm when the marginal problem is unsolvable
No full textsummary:In this paper we analyze the asymptotic behavior of the IPF algorithm for the problem of finding a 2x2x2 contingency table whose pair marginals are all equal to a specified 2x2 table, depending on a parameter. When this parameter lies below a certain threshold the marginal problem has no solution. We show that in this case the IPF has a “period three limit cycle” attracting all positive initial tables, and a bifurcation occur when the parameter crosses the threshold
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Confidence in ASCI scientific simulations
No full textThe US Department of Energy`s (DOE) Accelerated Strategic Computing Initiative (ASCI) program calls for the development of high end computing and advanced application simulations as one component of a program to eliminate reliance upon nuclear testing in the US nuclear weapons program. This paper presents results from the ASCI program`s examination of needs for focused validation and verification (V and V). These V and V activities will ensure that 100 TeraOP-scale ASCI simulation code development projects apply the appropriate means to achieve high confidence in the use of simulations for stockpile assessment and certification. The authors begin with an examination of the roles for model development and validation in the traditional scientific method. The traditional view is that the scientific method has two foundations, experimental and theoretical. While the traditional scientific method does not acknowledge the role for computing and simulation, this examination establishes a foundation for the extension of the traditional processes to include verification and scientific software development that results in the notional framework known as Sargent`s Framework. This framework elucidates the relationships between the processes of scientific model development, computational model verification and simulation validation. This paper presents a discussion of the methodologies and practices that the ASCI program will use to establish confidence in large-scale scientific simulations. While the effort for a focused program in V and V is just getting started, the ASCI program has been underway for a couple of years. The authors discuss some V and V activities and preliminary results from the ALEGRA simulation code that is under development for ASCI. The breadth of physical phenomena and the advanced computational algorithms that are employed by ALEGRA make it a subject for V and V that should typify what is required for many ASCI simulations
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The ASCI PSE Milepost: Run-Time Systems Performance Tests
No full textThe Accelerated Strategic Computing Initiative (ASCI) Problem Solving Environment (PSE) consists of the tools and libraries needed for the development of ASCI simulation codes on ASCI machines. The recently completed ASCI PSE Milepost demonstrated that this software environment is available and functional at the scale used for application mileposts on ASCI White. As part of the PSE Milepost, we performed extensive performance testing of several critical run-time based systems. In this paper, we present microbenchmark results that compare the MPI [5], Pthreads and OpenMP [7, 8] implementations on ASCI White and ASCI Blue Pacific. Our results demonstrate that these run-time systems on White have improved sufficiently to accommodate the machine's approximately four-fold increase in processing capability over Blue Pacific
An alternate way of collecting, storing, and dissecting Neurospora asci.
No full textTetrad analysis may be accomplished either with ordered asci squeezed from perithecia, or with asci shot as an unordered group at a target slab of agar (Perkins 1966, Neurospora Newsl. 9:11)
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Constructing the ASCI computational grid
No full textThe Accelerated Strategic Computing Initiative (ASCI) computational grid is being constructed to interconnect the high performance computing resources of the nuclear weapons complex. The grid will simplify access to the diverse computing, storage, network, and visualization resources, and will enable the coordinated use of shared resources regardless of location. To match existing hardware platforms, required security services, and current simulation practices, the Globus MetaComputing Toolkit was selected to provide core grid services. The ASCI grid extends Globus functionality by operating as an independent grid, incorporating Kerberos-based security, interfacing to Sandia's Cplant{trademark},and extending job monitoring services. To fully meet ASCI's needs, the architecture layers distributed work management and criteria-driven resource selection services on top of Globus. These services simplify the grid interface by allowing users to simply request ''run code X anywhere''. This paper describes the initial design and prototype of the ASCI grid
LLNL Site-Specific ASCI Software Quality Engineering Recommended Practices
No full textThe LLNL Site-Specific Advanced Simulation and Computing (ASCI) Software Quality Engineering Recommended Practices VI.I\u27\u27 document describes a set of recommended software quality engineering (SQE) practices for ASCI code projects at Lawrence Livermore National Laboratory (LLNL). In this context, SQE is defined as the process of building quality into software products by applying the appropriate guiding principles and management practices. Continual code improvement and ongoing process improvement are expected benefits. Certain practices are recommended, although projects may select the specific activities they wish to improve, and the appropriate time lines for such actions. Additionally, projects can rely on the guidance of this document when generating ASCI Verification and Validation (VSrV) deliverables. ASCI program managers will gather information about their software engineering practices and improvement. This information can be shared to leverage the best SQE practices among development organizations. It will further be used to ensure the currency and vitality of the recommended practices. This Overview is intended to provide basic information to the LLNL ASCI software management and development staff from the \u27\u27LLNL Site-Specific ASCI Software Quality Engineering Recommended Practices VI.I\u27\u27 document. Additionally the Overview provides steps to using the \u27\u27LLNL Site-Specific ASCI Software Quality Engineering Recommended Practices VI.I\u27\u27 document. For definitions of terminology and acronyms, refer to the Glossary and Acronyms sections in the \u27\u27LLNL Site-Specific ASCI Software Quality Engineering Recommended Practices VI.I\u2
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