Jeremiah P. Ostriker - US grants

Under this award, Princeton University will purchase CONVEX mini- supercomputer facilities for theoretical and observational investigations. Primary use will be for large scale simulations in cosmology to test the currently considered theoretical models against the increasingly detailed observations of large scale structure and the background radiation fields. The local facilities will be used both for preliminary modelling and for manipulation and display of the results obtained from NSF supported supercomputer facilities. Also significant will be use for processing of both optical and radio images. For both applications, the C-220 with its speed, large memory (512 Mb), and efficient FFT routines is ideal. Princeton University is providing 50% of the purchase price in a cost-sharing arrangement.

This award will support a two-year U.S.-Japan cooperative research project between Professor Jeremiah Ostriker, Princeton University Observatory, and Professor Humitaka Sato, Department of Physics, Kyoto University. The project, which will include Professor Edwin Turner of the Princeton University Observatory as co-investigator on the U.S. side, brings together American and Japanese theoretical astrophysicists to study problems connected with the formation of galaxies and cosmic large scale structure. On the Japanese side, the research group includes scientists from the National Astronomical Observatory and the Tokyo Metropolitan University as well as Kyoto University. Among the studies on galaxy formation to be investigated are: imprints on the microwave background, phase transition generated structure formation, non-zero cosmological constant cosmologies, the relation of the intergalactic medium to background radiation fields, quasar statistics, structure formation by Doppler instability, gravitational lens statistics, phase transitions in the early universe, and related topics. Most of these projects will emphasize physics other than the purely gravitational interactions that have been studied most thoroughly in the past. It is hoped that this joint study will lead to more permanent contacts between the two research communities.

Ostriker 9318185 The Grand Challenge Application Groups competition provides one mechanism for the support of multidisciplinary teams of scientists and engineers to meet the goals of the High Performance Computing and Communications (HPCC) Initiative in Fiscal Year 1993. The ideal proposal provided not only the opportunity to achieve significant progress on (1) a fundamental problem in science or engineering whose solution could be advanced by applying high performance computing techniques and resources, or (2) enabling technologies which facilitate those advances, but also significant interactions between scientific and computational activities, usually involving mathematical, computer or computational scientist, that would have impact in high performance computational activities beyond the specific scientific or engineering problem area(s) or discipline being studied. This project brings together a balanced, critical mass team of astrophysicists, computational scientists and computer scientists, as well as the technical resources of two NSF supercomputing centers, to mount a focused attack on what is presently one of the most exciting and fundamental problems in the physical sciences: "What is the origin of large-scale structure in the universe and how do galaxies form?" There is abundant observational data sufficient knowledge of the physical laws and mathematical techniques required to understand the origin and evolution of cosmic structure. Yet, it is difficult to confront theory with observation in detail owing to the inherent complexity of these systems and the difficulty of simulating multiple length-scale interactions. However, recent developments in multiscale numerical algorithms by members of our Grand Challenge Application Group (GCAG) and their efficient implementation on scaleable parallel supercomputers should enable the investigators to overcome these limitations. The GCAG will explore the use of: (i) different numerical algorithms (grid-based, particle-based, and hybrid ( grid+particle) to solve the physical equations governing gas, radiation, dark matter and gravity in an expanding universe; (ii) different adaptation strategies (adaptive mesh refinement, hierarchical tree) to achieve efficient, multiscale solvers capable of resolving length scales of interest over 4-6 orders of magnitude; (iii) different programming models (data parallel, SPMD, object parallel) to express these complex, adaptive algorithms in an efficient and portable way on different parallel architectures (TMC's CM5, Intel PARAGON, Cray T3D, Convex MPP) available to the investigators; and (iv) new software technology (e.g. pC++) to develop compilers, optimization designs and performance analysis tools which allow the most efficient implementation of the above strategies in order to expose the various computational and computer science issues required to construct a portable, scaleable application for teraflop systems expected later in this decade. This unique numerical laboratory-will allow the investigators to compare theories of the origin of large-scale structure with the observed universe, to discard incorrect models and hopefully to determine the elements of a viable theory. This HPCC Grand Challenge will be extremely data and UO intensive, pushing current hardware and software systems and solutions to and beyond their limits. The investigators will work with staffs of the Pittsburgh and Illinois supercomputer centers as well as the computer vendors to develop practical and efficient strategies for the storage, visualization and analysis of massive numerical data sets of use to this and other HPCC applications. This award is being supported by the Advanced Projects Research Agency as well as NSF programs in astronomy and computer sciences.

Advancing our understanding in a wide range of scientific and engineering fields require the solution of the fluid equations over a very large range of densities and physical scales. These problems, which are not soluble on the current generation of computers, can be solved with the new generation of massively parallel high performance computers using object oriented languages and are likely to form one of the most important scientific applications of these machines. The MAE and Astrophysics departments at Princeton are at the forefront of research into the development of numerical algorithms and computer technology to utilize the next generation of machines in this effort. The engineering and scientific goals are the applications to aerodynamics (the design of airplanes, cars and ships); to turbulence research; and to structure formation in the universe. Progress in these different application areas requires a continuing research effort toward the development of algorithms amenable to parallel processing, automatic grid adaption, coloring schemes for domain decomposition of an arbitrary unstructured tetrahedral grid, and implementation of efficient message passing algorithms to reduce the communication costs on distributed memory architectures. These problems are generic, and not specific to a particular field of application. It is felt that a multi-disciplinary approach to the study of such problems would greatly benefit the training of students and enhance the effective use of high performance computing in research. The MAE and Astrophysics departments have collaborated in this effort in the past, and will continue to do so in the future. We request support for five graduate students to be trained in the design of algorithms for the numerical solution of partial differential equations using massively parallel computer platforms and the application of complex hydrocodes to engineering and physics problems ranging from turbulence research in aerodyna mics to the evolution of cosmological structure.

9413515 Ostriker This award is for the acquisition of a massively parallel, scalable parallel computer. The planned computer will allow development and running of computer codes at Princeton and, for those problems requiring a more powerful computer, running the same codes at a supercomputing center. The research supported by this computing platform consists of the numerical study of hydrodynamics. The application areas to be studied are aerodynamics, turbulence research, and structure formation in the universe. These application areas are typical of computational grand challenges requiring substantial computational resources to solve. ***

ABSTRACT AST-9424416 Ostriker, Jeremiah P. This theoretical research project, directed by Dr. Ostriker, has the objective of elucidating the physical processes occurring in active and quiescent galactic nuclei. While there is general agreement that a proper model will include a dense stellar system and in all likelihood a gaseous disc and one or more massive black holes, the detailed mechanism whereby the prodigious energy output is achieved remains poorly understood. The focus of this research is not on the electrodynamics or relativistic dynamics in the vicinity of a black hole, but on the physical environment in dense stellar systems. Three related areas will be studied: (1) hydrodynamics of time-dependent accretion flows; (2) evolution of dense stellar systems; and (3) the union of the previous two subjects, i.e. physical processes in systems containing both accretion flows and dense stellar systems. ***

9729854 Dobkin, Davis Princeton University CISE Research Instrumentation :Instrumentation Support for Graphics and Visualization Research at Princeton This research instrumentation enables research projects in:- Virtual Environments,- Scientific Visualization, and- Digital Media. The Departments of Computer Science and Astrophysics at Princeton University will purchase equipment for high performance graphics and for outputting of high resolution graphics in various formats (video, hardcopy and slides). The equipment will be used for several research projects, including in particular: (1) work in walkthroughs of buildings and cities, (2) visualization of scientific data and (3) digital techniques in multimedia. The equipment requested will be used by faculty, graduate students and undergraduates in both computer science and astrophysics to support individual and cross-disciplinary research projects. An important consequence of the proposed projects is that they not only enhance the current faculty and student research and education but they also act as a catalyst for new collaborations between these two departments and other related science and engineering departments at Princeton. The synergy created will thus make the whole significantly greater than the sum of the parts.

This Integrative Graduate Education and Research Training (IGERT) award supports establishment of a multidisciplinary graduate training program of education and research at Princeton to provide the next generation of computer scientists and users of high-performance computing with integrated graduate training across disciplinary boundaries. On one hand, dramatic advances in computer technology are poised to revolutionize computational science as an equal partner of theory and experiment, but their nature is such that harnessing them will require cross-disciplinary fertilization and expertise in both application areas and computer science. At the same time, advances in computer science will increasingly be driven by knowledge of applications, both scientific simulations and others. The PICAS program will address the entire computational and information pipeline in a variety of areas, from models and methods through parallel algorithms and systems to immersive visualization and information management. It will train a new breed of researchers to cross-disciplinary boundaries, develop new areas between disciplines, and exploit synergies. Centered around the computer science department, the program will include many departments throughout the university. Program components include curriculum development, cross-department advising, integrated research across disciplines, cross-cutting annual thematic programs to focus collaboration, and activities like a recent interdisciplinary seminar series that attracts many researchers from various local institutions.

IGERT is an NSF-wide program intended to facilitate the establishment of innovative, research-based graduate programs that will train a diverse group of scientists and engineers to be well-prepared to take advantage of a broad spectrum of career options. IGERT provides doctoral institutions with an opportunity to develop new, well-focussed multidisciplinary graduate programs that transcend organizational boundaries and unite faculty from several departments or institutions to establish a highly interactive, collaborative environment for both training and research. In this second year of the program, awards are being made to twenty-one institutions for programs that collectively span all areas of science and engineering supported by NSF. This specific award is supported by funds from the Directorates for Computer and Information Science and Engineering, for Mathematical and Physical Sciences (Office of Multidisciplinary Activities), for Engineering, and for Education and Human Resources.

9818308
Singh, Jaswinder Pal
Ostriker, Jeremiah
Princeton University

Applications and Programming Environments for Cache-Coherent Distributed Memory Machines

This research instrumentation enables research projects in:
- Parallel Applications and Programming Environments for Computational Cosmology on Cache-Coherent DSM Architectures,
- Parallel Applications and Programming Environments for Computational Protein Structure Determination on Cache-Coherent DSM Architectures, and
- Parallel Workload for System Evaluation and their Implications for Software and Hardware.
To support integrated application-driven research in the aforementioned projects, this award contributes to the purchase of an upgrade to an existing 64-processor SGI Origin2000 multiprocessor by the Departments of Computer Science and Astrophysics together with the Princeton Plasma Physics Laboratory at Princeton University. The equipment will be used to continue and enhance the research projects listed and to support new projects between computer science and the Plasma Physics Laboratory. The first project, a collaboration between Computer Science and Astrophysics, deals with problems particularly challenging for parallel implementation due to the combination of interacting models and a highly irregular dynamic nature. The goals are to develop parallel algorithms and implementations for a range of computations, to develop generalizable and portable techniques preserving locality while providing load balance, to extend existing parallel languages; use runtime systems of these languages, to build libraries of partitioning techniques and
algorithms. The second project, a collaboration between CS and the School of Medicine at Stanford University, with similar goals, simulates inherently slow processes in structural biology. The last project will broaden the set of workloads available. The SPLASH suites of parallel applications in critical emerging application areas serve as benchmarks for architectural studies, as well as testbeds for programming languages and compilers.

AST 0206299
Cen

The formation and evolution of cosmic structures, including galaxies, clusters of galaxies and large-scale structure, are fundamental problems of modern cosmology. While the Big Bang picture of how the Universe began is generally accepted, the details of how and when structures developed and formed are in hot debate. On scales larger than clusters of galaxies (>10 million light years across) it is generally believed that gravity is the dominant force and structures grow from small initial seeds planted in the very early universe (<< 1 second since the Big Bang), because gravity is attractive and unstable. However, on smaller scales gas hydrodynamics, microphysics (i.e., forces on atomic scales) and star formation processes play progressively more important roles in shaping and determining when galaxies form and how they evolve; the picture at these smaller scales is much less clear. The radiation field, especially, the ultra-violet radiation that is capable of ionizing atomic hydrogen must play a very important role in these processes. In particular, it determines when atomic hydrogen is fully ionized and the universe is cleared of hydrogen "fog" and becomes transparent to distant sources. This epoch has been characterized as the "end of the dark ages". Since radiation controls the evolution of the thermodynamic state of the gas, a fraction of which is subsequently incorporated into stars, it is essential to include radiation hydrodynamics in full detail in cosmological computer simulations in order to provide answers to many of the important questions in modern cosmology. This is a formidable task to tackle even with the fastest supercomputers today. Dr. Cen and his collaborators have developed an efficient way to compute this complicated situation and begun to carry out a program that should help provide some clues about how the radiation field and the matter evolve with time.
***

AST-0407176
Cen

Recent observations from the Wilkinson Microwave Anisotropy Probe and the Sloan Digital Sky Survey together suggest that the universal reionization may be prolonged and much more complex than previously thought. This research will systematically study all of the astrophysical processes relevant to the universal reionization and heating process, to set up a working framework for proper interpretation of major observations of the high redshift universe. Semi-analytic methods and state-of-the-art hydrodynamical and radiation hydrodynamical simulations will be used both for this, and to focus on gaining a fuller understanding of star formation at high redshift. Informed comparison between observations and theoretical predictions should help with working out the correct cosmological model.

This research will feed into a continuing outreach program intended to enhance the scientific understanding of cosmological research by the general public. Results will be visualized and presented through various channels, including planetaria and public television. The technological demand of the simulations will also test advances in high performance computing.

AST-0507521
Cen

It is well established that gravitational instability is the dominant force driving the formation of baryonic structures. However, feedback processes on the intergalactic medium (IGM) from star formation are not well understood, although observationally the phenomenon of galactic super-winds (GSW) is common in both low redshift starburst galaxies and high redshift Lyman break galaxies. Lack of an adequate treatment of GSW and other important physical processes in cosmological hydrodynamic simulations hampers a full understanding of the evolution of the IGM. This research will carry out adaptive mesh refinement hydrodynamic simulations with all likely relevant physical processes carefully treated, to compute more precisely the evolution of the IGM, and specifically, the warm-hot IGM (WHIM) at low redshift and the Lyman alpha forest at moderate redshift. This will produce a detailed characterization of the distribution of the WHIM, allowing future observational determination of the fraction of the cosmic baryons in this state. It will also help to quantify systematic errors, again allowing future observational constraints on the matter power spectrum to be accurate enough to shed useful light on inflationary theories. This research will set up an adequate framework to interpret the vast observational database on evolution of the IGM, in a physically self-consistent fashion.

Broader impacts of this work include continuing an effective outreach program to the general public, using visualizations presented through effective channels, such as at the Rose-Hayden Planetarium of the American Museum of Natural History, and public television programs such as Nova.

AST-0708960/0707505/0708309
Norman/Ostriker/Ricotti

This is a three-award collaborative project, led by Dr Norman, to harness the power of future petascale supercomputers for self-consistent simulations of early structure formation in cosmologically representative volumes. Astronomers' expectation of what will be observed at high redshifts (above 7) by future major facilities is largely based on theoretical and numerical models of the early growth of cosmic structure in a standard Lambda-CDM cosmological framework. The new simulations will span local and global scales using adaptive mesh refinement (AMR) technology developed specifically for petascale computers. This enables simulations with ten billion particles, a spatial dynamic range of a hundred thousand, and complex baryonic physics including radiative and chemical feedback. As theories are at present poorly constrained by observations, an equally important effort will be a rigorous attempt at uncertainty quantification and sensitivity analysis. The study will thus address forefront questions in cosmology using the most complete physical models running on the most powerful computers, analyzed using best practices. The result will be comprehensive models of early cosmic evolution along with a rigorous assessment of their predictive value.

This work will substantially advance the state-of-the-art in numerical multi-physics cosmological simulations, which can be expected to continue previous successful impacts of code availability, both within and outside of the astrophysics community. The new petascale methodologies will also be publicized well outside the usual astronomy circles, and the enhanced version of the Enzo community code will be released to the public. In addition, both the numerical results and the synthetic observations will be published to the international research community using mechanisms provided by the National Virtual Observatory.

This work is for the acquisition of a high-performance computer cluster for computational astrophysics and for the analysis of data from the Sloan Digital Sky Survey, Wilkinson Microwave Anisotropy Probe, the Atacama Cosmology Telescope, and the Southern Cosmology Survey. The cluster will be available to researchers from several institutions and will be available for the training of students in high-performance computing.

Intellectual Merit:
The proposed work is an exploratory research effort to automatically extract parallelism from sequential program and to schedule the resulting fine-grained computational elements on manycore processors. The goal is to allow existing sequential programs to run on many-core processors efficiently and build the foundation to enable a hybrid approach, involving message passing and
shared memory, to address petascale programmability
This exploratory research will attack the following issues:
? Design a compiler to decompose the code running on a single node into fine-grained computation tasks to utilize the collection of cores on a single chip.
? Develop a highly-efficient runtime system to schedule fine-grained tasks to optimize for available parallelisms and to maximize on-chip cache locality to overcome off-chip memory latency and bandwidth constrains.
? Evaluate our success with a newly released benchmark suite PARSEC which allows us to compare our success with hand-tuned parallel solutions. We also plan to evaluate one computational science application

Broader Impact:
The potential impact of this project is significant. First, the success of the proposed research would advance knowledge and understanding in parallel programming to exploit the power of future parallel machines. Second, the success of the project will accelerate software developmentfor petascale computing. Third, the proposed compiler and runtime systems will provide the
capability to run existing large-scale computational science programs on petascale computers without burdensome programming efforts.

This MRI award will serve to purchase a 256 Processor/1536 core SGI Altix UV1000 with 9.2 TB of RAM and 14.4 TB of raw scratch disk space. The instrument will provide scientists at Princeton University, the Institute for Advanced Studies, and partner institutions with the computational resources needed to model multi-scale phenomena in the sciences and engineering. The flexibility of the Altix architecture, which supports both shared and distributed memory applications, along with an outstanding bus architecture to support the addition of extra processing units such as GPGPUs is an ideal platform for developing algorithms for multi-scale problems. The setting of the instrument in the University?s High Performance Computing Research Center will facilitate a cross-disciplinary approach combining expertise in applied mathematics, computer science and domain-specific disciplines enabling innovative approaches for memory intensive applications. The new instrument will play an essential role in educating a new generation of scientists and training students across many disciplines in the use of advanced modeling tools on modern computer platforms, contributing to new graduate student certificate programs offered by PACM, the Program in Applied and Computational Mathematics, and PICSciE, the Princeton Institute for Computational Science and Engineering. Finally, the instrument will provide a necessary link between local and national facilities, preparing the Princeton scientific community to the emerging multicore and massively parallel architectures of the future.

The instrument will enhance international scientific cooperation by contributing to projects like the Munich-Princeton collaboration in cosmological computational science, and will contribute to science education of the general public through collaboration with the American Museum of Natural History in New York City, with planned new visualizations for use in the Cosmos series and in conjunction with the Museum?s ongoing public education work on earthquakes and geologic movement. Women?s participation in computational projects enabled by the instrument will set examples to encourage greater access of women to science. Finally, access provided to partners at
California State University-Northridge will contribute to training minority scientists and engineers.