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Technologies and tools for high-performance distributed computing. Final report

Description: In this project we studied the practical use of the MPI message-passing interface in advanced distributed computing environments. We built on the existing software infrastructure provided by the Globus Toolkit{trademark}, the MPICH portable implementation of MPI, and the MPICH-G integration of MPICH with Globus. As a result of this project we have replaced MPICH-G with its successor MPICH-G2, which is also an integration of MPICH with Globus. MPICH-G2 delivers significant improvements in message passing performance when compared to its predecessor MPICH-G and was based on superior software design principles resulting in a software base that was much easier to make the functional extensions and improvements we did. Using Globus services we replaced the default implementation of MPI's collective operations in MPICH-G2 with more efficient multilevel topology-aware collective operations which, in turn, led to the development of a new timing methodology for broadcasts [8]. MPICH-G2 was extended to include client/server functionality from the MPI-2 standard [23] to facilitate remote visualization applications and, through the use of MPI idioms, MPICH-G2 provided application-level control of quality-of-service parameters as well as application-level discovery of underlying Grid-topology information. Finally, MPICH-G2 was successfully used in a number of applications including an award-winning record-setting computation in numerical relativity. In the sections that follow we describe in detail the accomplishments of this project, we present experimental results quantifying the performance improvements, and conclude with a discussion of our applications experiences. This project resulted in a significant increase in the utility of MPICH-G2.
Date: May 1, 2000
Creator: Karonis, Nicholas T.
Partner: UNT Libraries Government Documents Department

A User's Manual for MASH V1.5 - A Monte Carlo Adjoint Shielding Code System

Description: The Monte Carlo ~djoint ~ielding Code System, MASH, calculates neutron and gamma- ray environments and radiation protection factors for armored military vehicles, structures, trenches, and other shielding configurations by coupling a forward discrete ordinates air- over-ground transport calculation with an adjoint Monte Carlo treatment of the shielding geometry. Efficiency and optimum use of computer time are emphasized. The code system includes the GRTUNCL and DORT codes for air-over-ground transport calculations, the MORSE code with the GIFT5 combinatorial geometry package for adjoint shielding calculations, and several peripheral codes that perform the required data preparations, transformations, and coupling functions. The current version, MASH v 1.5, is the successor to the original MASH v 1.0 code system initially developed at Oak Ridge National Laboratory (ORNL). The discrete ordinates calculation determines the fluence on a coupling surface surrounding the shielding geometry due to an external neutron/gamma-ray source. The Monte Carlo calculation determines the effectiveness of the fluence at that surface in causing a response in a detector within the shielding geometry, i.e., the "dose importance" of the coupling surface fluence. A coupling code folds the fluence together with the dose importance, giving the desired dose response. The coupling code can determine the dose response as a function of the shielding geometry orientation relative to the source, distance from the source, and energy response of the detector. This user's manual includes a short description of each code, the input required to execute the code along with some helpful input data notes, and a representative sample problem.
Date: October 1998
Creator: Slater, C. O.; Barnes, J. M.; Johnson, J. O. & Drischler, J. D.
Partner: UNT Libraries Government Documents Department

Status of the MCNP{trademark}/LCS{trademark} merger project

Description: The MCNPX code is now in limited release in a beta-test version. We provide a brief status report on the physics modules now in the code and of the enhanced capabilities to use new evaluated neutron data. We also present new benchmark calculations in which LAHET and MCNPX are compared with experimental results from the Japan Atomic Energy Research Institute.
Date: April 19, 1998
Creator: Hughes, H.G.; Adams, K.J.; Chadwick, M.B.; Comly, J.C.; Frankle, S.C.; Hendricks, J.S. et al.
Partner: UNT Libraries Government Documents Department

Impedance studies: Part 1, A composition rule

Description: The impedances and the loss factors experienced by a particle beam that circulates in the APS storage ring play an essential role in the studies of the beam instability problem. Due to a large variety of structures in the ring, the computation of these parameters amounts to enormous work. During the last months, this was tackled numerically by invoking the MAFIA family, a set of codes developed mainly at DESY. The results are to be reported in several LS notes. This note is the first part and will discuss a composition rule that we observed in our calculations. The composition rule can be stated as follows. For a complicated structure, one may decompose it into simple components and compose these components to form new structures. Under certain conditions, the old and the new structures will give the same loss factors. This rule is in analogy to and an extension of the law of addition of resistances in sequence in the conventional circuit theory. We will discuss two examples to illustrate this rule.
Date: July 1, 1988
Creator: Chou, W. & Jin, Y.
Partner: UNT Libraries Government Documents Department

MCNP{sup TM} criticality primer and training experiences

Description: With the closure of many experimental facilities, the nuclear criticality safety analyst is increasingly required to rely on computer calculations to identify safe limits for the handling and storage of fissile materials. However, the analyst may have little experience with the specific codes available at his or her facility. Usually, the codes are quite complex, black boxes capable of analyzing numerous problems with a myriad of input options. Documentation for these codes is designed to cover all the possible configurations and types of analyses but does not give much detail on any particular type of analysis. For criticality calculations, the user of a code is primarily interested in the value of the effective multiplication factor for a system (k{sub eff}). Most codes will provide this, and truckloads of other information that may be less pertinent to criticality calculations. Based on discussions with code users in the nuclear criticality safety community, it was decided that a simple document discussing the ins and outs of criticality calculations with specific codes would be quite useful. The Transport Methods Group, XTM, at Los Alamos National Laboratory (LANL) decided to develop a primer for criticality calculations with their Monte Carlo code, MCNP. This was a joint task between LANL with a knowledge and understanding of the nuances and capabilities of MCNP and the University of New Mexico with a knowledge and understanding of nuclear criticality safety calculations and educating first time users of neutronics calculations. The initial problem was that the MCNP manual just contained too much information. Almost everything one needs to know about MCNP can be found in the manual; the problem is that there is more information than a user requires to do a simple k{sub eff} calculation. The basic concept of the primer was to distill the manual to create a ...
Date: September 1, 1995
Creator: Briesmeister, J.; Forster, R.A. & Busch, R.
Partner: UNT Libraries Government Documents Department

Estimation and interpretation of k{sub eff} confidence intervals in MCNP

Description: MCNP has three different, but correlated, estimators for Calculating k{sub eff} in nuclear criticality calculations: collision, absorption, and track length estimators. The combination of these three estimators, the three-combined k{sub eff} estimator, is shown to be the best k{sub eff} estimator available in MCNP for estimating k{sub eff} confidence intervals. Theoretically, the Gauss-Markov Theorem provides a solid foundation for MCNP`s three-combined estimator. Analytically, a statistical study, where the estimates are drawn using a known covariance matrix, shows that the three-combined estimator is superior to the individual estimator with the smallest variance. The importance of MCNP`s batch statistics is demonstrated by an investigation of the effects of individual estimator variance bias on the combination of estimators, both heuristically with the analytical study and emprically with MCNP.
Date: July 1, 1995
Creator: Urbatsch, T.J.; Forster, R.A.; Prael, R.E. & Beckman, R.J.
Partner: UNT Libraries Government Documents Department

Status of electron transport in MCNP{trademark}

Description: In recent years, an ongoing project within the radiation transport group (XTM) at Los Alamos National Laboratory has been the implementation and validation of an electron transport capability in the Monte Carlo code NICNP. In this paper the authors document the continuous-energy electron transport methods currently in use in MCNP, and describes a recent improvement of the energy-loss straggling algorithm. MCNP also supports electron transport calculations in a multigroup mode.
Date: September 1, 1995
Creator: Hughes, H.G.
Partner: UNT Libraries Government Documents Department

Review of the international conference on nuclear criticality-issues, discussions, and challenges

Description: The Fifth International Conference on Nuclear Criticality Safety (ICNC`95) was held September 17-22, 1995, in Albuquerque, New Mexico, USA. Organization and support for the conference was provided by the Sandia National Laboratories (SNL), Los Alamos National Laboratory (LANL), the University of New Mexico, and the Organization for Economic Cooperation and Development (OECD). This conference traces its history back to 1981 when a group of select criticality safety specialists (mostly experimentalists) from France, Germany, Japan, the United Kingdom, and the United States participated in a small conference at LANL in the United States. The motivation for the conference had been provided by Dr. J. C. Manaranche of France who had asked D. Smith and G. E. Whitesides of the United States if it would be possible for the French experimentalists to be able to visit the experimental facilities at LANL. This first conference was followed by a similar conference held in Dijon, France, in 1993. Then in 1987 the conference was hosted by the Japanese and opened to much wider participation by criticality safety specialists involved in experiments, methods development and analysis, and operations. With the 1987 conference in Japan and the fourth conference (ICNC`91) held in the United Kingdom, the interest and international participation by the criticality safety community has grown rapidly. With this background, the occasion of ICNC`95 was one of much expectation.
Date: December 31, 1995
Creator: Parks, C.V. & Whitesides, G.E.
Partner: UNT Libraries Government Documents Department

Simulation of PEP-II beam position monitors

Description: The authors use MAFIA to analyze the PEP-II button-type beam position monitors (BPMs). Employing proper termination of the BPM into a coaxial cable, the output signal at the BPM can be determined. Thus the issues of sensitivity and power output can be addressed quantitatively, including all transient effects and wakefields. Besides this first quantitative analysis of a true BPM 3D structure, they find that internal resonant modes are a major source of high value narrow-band impedances. These are evaluated and methods are presented to suppress these parasitic resonances below the tolerable limit of multibunch instabilities.
Date: May 1, 1995
Creator: Ng, C.K.; Weiland, T.; Martin, D.; Smith, S. & Kurita, N.
Partner: UNT Libraries Government Documents Department

A portable, parallel, object-oriented Monte Carlo neutron transport code in C++

Description: We have developed a multi-group Monte Carlo neutron transport code using C++ and the Parallel Object-Oriented Methods and Applications (POOMA) class library. This transport code, called MC++, currently computes k and {alpha}-eigenvalues and is portable to and runs parallel on a wide variety of platforms, including MPPs, clustered SMPs, and individual workstations. It contains appropriate classes and abstractions for particle transport and, through the use of POOMA, for portable parallelism. Current capabilities of MC++ are discussed, along with physics and performance results on a variety of hardware, including all Accelerated Strategic Computing Initiative (ASCI) hardware. Current parallel performance indicates the ability to compute {alpha}-eigenvalues in seconds to minutes rather than hours to days. Future plans and the implementation of a general transport physics framework are also discussed.
Date: May 1, 1997
Creator: Lee, S.R.; Cummings, J.C. & Nolen, S.D.
Partner: UNT Libraries Government Documents Department

MPDATA: A positive definite solver for geophysical flows

Description: This article is a review of MPDATA, a class of methods for the numerical simulation of advection based on the sign-preserving properties of upstream differencing. MPDATA was designed originally as an inexpensive alternative to flux-limited schemes for evaluating the transport of nonnegative thermodynamic variables (such as liquid water or water vapour) in atmospheric models. During the last decade, MPDATA has evolved from a simple advection scheme to a general approach for integrating the conservation laws of geophysical fluids on micro-to-planetary scales. The purpose of this paper is to summarize the basic concepts leading to a family of MPDATA schemes, review the existing MPDATA options, as well as to demonstrate the efficacy of the approach using diverse examples of complex geophysical flows.
Date: March 1, 1997
Creator: Smolarkiewicz, P.K. & Margolin, L.G.
Partner: UNT Libraries Government Documents Department

Differential sensitivity theory applied to the MESA2D code for multi-material problems

Description: The technique called Differential Sensitivity Theory (DST) is extended to the multi-component system of equations solved by the MESA2D hydrocode. DST uses adjoint techniques to determine exact sensitivity derivatives, i.e., if R is a calculation result of interest (response R) and {alpha}{sub i} is a calculation input (parameter {alpha}{sub i}), then {partial_derivative}R/{partial_derivative}{alpha}{sub i} is defined as the sensitivity. The advantage of using DST is that for an n-parameter problem all n sensitivities can be obtained by integrating the solutions from only two calculations, a MESA calculation and its corresponding adjoint calculation using an Adjoint Continuum Mechanics (ACM) code. Previous papers have described application of the technique to one-dimensional, single-material problems. This work presents the derivation and solution of the additional adjoint equations for the purpose of computing sensitivities for two-dimensional, multi-component problems. As an example, results for a multi-material flyer plate impact problem featuring an oblique impact are given.
Date: September 1995
Creator: Henninger, R. J.; Maudlin, P. J. & Harstad, E. N.
Partner: UNT Libraries Government Documents Department

Direct calculation of leak path factors for highly compartmentalized buildings

Description: The large, highly compartmentalized configurations of buildings at many Department of Energy (DOE) facilities call the validity of traditional, simplistic methods for estimating contaminant leak path factors (LPFs) into question. Conversely, rigorous calculation of LPFs using detailed flow-field analysis computer codes is impractical for routine analysis. This paper describes a recent application of a rigorous, yet practical, method of calculating LPFs for the Chemical and Metallurgical Research (CMR) Facility at Los Alamos National Laboratory (LANL). The approach involves computer simulation of airborne contaminant transport using the MELCOR computer code. MELCOR is a general-purpose, fluid flow and aerosol transport analysis code originally developed by the US Nuclear Regulatory Commission to evaluate the release, transport, and deposition of radionuclides in nuclear reactor systems. However, the fundamental mathematical models in the code and the modular code architecture make it suitable to the CMR analysis.
Date: December 1, 1998
Creator: Leonard, M.T. & McClure, P.R.
Partner: UNT Libraries Government Documents Department

MESQUITE design : issues in the development of a mesh quality improvement toolkit.

Description: Poor mesh quality is known to adversely affect both solution efficiency and accuracy. There has been considerable research on a wide variety of mesh improvement algorithms, but the impact of these algorithms on applications has been limited because they are typically embedded in particular meshing software packages. To rectify this situation, they are developing a stand-alone mesh quality improvement toolkit called MESQUITE. In this paper, the authors describe the motivation, goals, and design of MESQUITE and give some computational results using the underlying algorithms that show the benefit of such a package.
Date: March 26, 2002
Creator: Freitag, L.; Leurent, T.; Knupp, P. & Melander, D.
Partner: UNT Libraries Government Documents Department

MACE 2.0 reference manual and guide.

Description: MACE is a program that searches for finite models of first-order statements. The statement to be modeled is first translated to clauses, then to relational clauses; finally for the given domain size, the ground instances are constructed. A Davis-Putnam-Loveland-Logeman procedure decides the propositional problem, and any models found are translated to first-order models. MACE is a useful complement to the theorem prover Otter, with Otter searching for proofs and MACE looking for countermodels.
Date: June 8, 2001
Creator: McCune, W.
Partner: UNT Libraries Government Documents Department

Mace4 reference manual and guide.

Description: Mace4 is a program that searches for finite models of first-order formulas. For a given domain size, all instances of the formulas over the domain are constructed. The result is a set of ground clauses with equality. Then, a decision procedure based on ground equational rewriting is applied. If satisfiability is detected, one or more models are printed. Mace4 is a useful complement to first-order theorem provers, with the prover searching for proofs and Mace4 looking for countermodels, and it is useful for work on finite algebras. Mace4 performs better on equational problems than did our previous model-searching program Mace2.
Date: October 27, 2003
Creator: McCune, W.
Partner: UNT Libraries Government Documents Department

Development of a Fully-Automated Monte Carlo Burnup Code Monteburns

Description: Several computer codes have been developed to perform nuclear burnup calculations over the past few decades. In addition, because of advances in computer technology, it recently has become more desirable to use Monte Carlo techniques for such problems. Monte Carlo techniques generally offer two distinct advantages over discrete ordinate methods: (1) the use of continuous energy cross sections and (2) the ability to model detailed, complex, three-dimensional (3-D) geometries. These advantages allow more accurate burnup results to be obtained, provided that the user possesses the required computing power (which is required for discrete ordinate methods as well). Several linkage codes have been written that combine a Monte Carlo N-particle transport code (such as MCNP<sup>TM</sup>) with a radioactive decay and burnup code. This paper describes one such code that was written at Los Alamos National Laboratory: monteburns. Monteburns links MCNP with the isotope generation and depletion code ORIGEN2. The basis for the development of monteburns was the need for a fully automated code that could perform accurate burnup (and other) calculations for any 3-D system (accelerator-driven or a full reactor core). Before the initial development of monteburns, a list of desired attributes was made and is given below. o The code should be fully automated (that is, after the input is set up, no further user interaction is required). . The code should allow for the irradiation of several materials concurrently (each material is evaluated collectively in MCNP and burned separately in 0RIGEN2). o The code should allow the transfer of materials (shuffling) between regions in MCNP. . The code should allow any materials to be added or removed before, during, or after each step in an automated fashion. . The code should not require the user to provide input for 0RIGEN2 and should have minimal MCNP input file requirements (other ...
Date: January 1, 1999
Creator: Poston, D.I. & Trellue, H.R.
Partner: UNT Libraries Government Documents Department

Multipacting Simulation Study for 56 MHz Quarter Wave Resonator using 2D Code

Description: A beam excited 56 MHz Radio Frequency (RF) Niobium Quarter Wave Resonator (QWR) has been proposed to enhance RHIC beam luminosity and bunching. Being a RF cavity, multipacting is expected; therefore an extensive study was carried out with the Multipac 2.1 2D simulation code. The study revealed that multipacting occurs in various bands up to peak surface electric field 50 kV/m and is concentrated mostly above the beam gap and on the outer conductor. To suppress multipacting, a ripple structure was introduced to the outer conductor and the phenomenon was successfully eliminated from the cavity.
Date: January 2, 2009
Creator: Naik,D. & Ben-Zvi, I.
Partner: UNT Libraries Government Documents Department

Geometric optimization of the 56 MHz SRF cavity and its frequency table

Description: It is essential to know the frequency of a Superconducting Radio Frequency (SRF) cavity at its 'just being fabricated' stage because frequency is the key parameter in constructing the cavity. In this paper, we report our work on assessing it. We can estimate the frequency change from stage to stage theoretically and/or by simulation. At the operating stage, the frequency can be calculated accurately, and, from this value, we obtain the frequencies at other stages. They are listed in a table that serves to check the processes from stage to stage. Equally important is optimizing the geometric shape of the SRF cavity so that the peak electric-field and peak magnetic-field are as low as possible. It is particularly desirable in the 56MHz SRF cavity of RHIC to maximize the frequency sensitivity of the slow tuner. After undertaking such optimization, our resultant peak electric-field is only 44.1MV/m, and the peak magnetic-field is 1049G at 2.5MV of voltage across the cavity gap. To quench superconductivity in an SRF cavity, it is reported that the limit of the peak magnetic-field is 1800G [1], and that of the peak electric-field is more than l00MV/m for a SRF cavity [2]. Our simulations employed the codes Superfish and Microwave Studio.
Date: October 1, 2008
Creator: Chang,X. & Ben-Zvi, I.
Partner: UNT Libraries Government Documents Department

MeshTV: scientific visualization and graphical analysis software

Description: The increasing data complexity engendered by the Accelerated Scientific Computing Initiative (ASCI) requires more capability in our scientific visualization software. B Division at Lawrence Livermore National Laboratory (LLNL) addresses these new and changing requirements with MeshTV. We began work on MeshTV around eight years ago, and have progressively refined the software to provide improved scientific analysis and visualization to well over 100 users at Liver-more, Los Alamos, Sandia, and in private industry. (U)
Date: February 8, 1999
Creator: Brugger, E S; Roberts, L & Wookey, S G
Partner: UNT Libraries Government Documents Department

MARS code developments

Description: Recent developments in the physical model of 1 MeV to 100 TeV hadron and lepton interactions with nuclei and atoms are described. These include a new nuclear cross section library, a model for soft pion production, the cascade-exciton model, the dual parton model, deuteron-nucleus and neutrino-nucleus interaction models, detailed description of mu, pi and anti p absorption and a unified treatment of muon and charged hadron electromagnetic interactions with matter. New algorithms are implemented into the MARS13(98) Monte Carlo code and benchmarked against experimental data. The code capabilities to simulate cascades and generate a variety of results in complex media have been also enhanced.
Date: December 1, 1998
Creator: N.V.Mokhov, S.I.Striganov, A.Van Ginneken, S.G.Mashnik, A.J.Sierk and J.Ranft
Partner: UNT Libraries Government Documents Department

3D simulation studies of tokamak plasmas using MHD and extended-MHD models

Description: The M3D (Multi-level 3D) tokamak simulation project aims at the simulation of tokamak plasmas using a multi-level tokamak code package. Several current applications using MHD and Extended-MHD models are presented; high-{beta} disruption studies in reversed shear plasmas using the MHD level MH3D code, {omega}{sub *i} stabilization and nonlinear island saturation of TAE mode using the hybrid particle/MHD level MH3D-K code, and unstructured mesh MH3D{sup ++} code studies. In particular, three internal mode disruption mechanisms are identified from simulation results which agree which agree well with experimental data.
Date: December 31, 1996
Creator: Park, W.; Chang, Z.; Fredrickson, E. & Fu, G.Y.
Partner: UNT Libraries Government Documents Department