Olaf Storaasli | Other - Academia.edu (original) (raw)

Papers by Olaf Storaasli

29th Structures, Structural Dynamics and Materials Conference, Apr 18, 1988

Computing Systems in Engineering, Dec 1, 1993

Computing speed is leaping forward by several orders of magnitude each decade. Engineers and scie... more Computing speed is leaping forward by several orders of magnitude each decade. Engineers and scientists gathered at a NASA Langley symposium to discuss these exciting trends as they apply to parallel computational methods for large-scale structural analysis and design. Among the topics discussed were: large-scale static analysis; dynamic, transient, and thermal analysis; domain decomposition (substructuring); and nonlinear and numerical methods.

Recent developments in computer-aided structural design indicate a need for caputerized structura... more Recent developments in computer-aided structural design indicate a need for caputerized structural analysis techniques which are efficient for the repetitive analysis of large complex structures undergoing design nadifications. This paper describes such a technique based on a Taylor series approach. Results are presented for an idealized aircraft fuselage nidsection to demonstrate the efficierxy and accuracy of the technique. results show that satisfactory analyses of modified. structures may be obtained with the proposed technique, even for large changes in member sizes, for only a small fraction of the computational cost of a 111 reanalysis.

OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information), Dec 1, 2011

Parallel computers offer the opportunity to significantly reduce the computation time necessary t... more Parallel computers offer the opportunity to significantly reduce the computation time necessary to analyze large-scale aerospace structures. This paper presents algorithms developed for and implemented on a massively-parallel computers hereafter referred to as Scalable High Performance Computers (SHPC) for the most computationally intensive tasks involved in structural analysis, namely, generation and assembly of system matrices, solution of systems of equations and calculation of the eigenvalues and eigenvectors. Results on SHPC are presented for large-scale structural problems (i.e. Models of high speed civil transport). The goal of this research is to develop new efficient technique which extend structural analysis to SHPC and make large-scale structural analyses tractable.

NASA Tech Briefs, Oct 1, 1993

New algorithm developed to overcome deficiency of skyline storage scheme by use of variable-band ... more New algorithm developed to overcome deficiency of skyline storage scheme by use of variable-band storage scheme. Exploits both parallel and vector capabilities of modern high-performance computers. Gives engineers and designers opportunity to include more design variables and constraints during optimization of structures. Enables use of more refined finite-element meshes to obtain improved understanding of complex behaviors of aerospace structures leading to better, safer designs. Not only attractive for current supercomputers but also for next generation of shared-memory supercomputers.

This report documents findings and recommendations by the Ultrafast Computing Other terms used lo... more This report documents findings and recommendations by the Ultrafast Computing Other terms used locally are defined where they first occur. 14. SUBJECT TERMS computers, analysis, optimization, parallel processing, concurrent processing, aerospace design, computational engineering, high-performance computing 17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION 19. SECURITY CLASSIFICATION OF REPORT OF THIS PAGE

The Journal of Appellate Practice and Process, Mar 22, 2014

Computers & Structures, Feb 1, 1977

Results are presented of exploratory studies on the use of a minicomputer in conjunction with lar... more Results are presented of exploratory studies on the use of a minicomputer in conjunction with large-scale computers to perform structural design tasks, including data and program management, use of interactive graphics, and computations for structural analysis and design. An assessment is made of minicomputer use for the structural model definition and checking and for interpreting results. Included are results of computational experiments demonstrating the advantages of using both a minicomputer and a large computer to solve a large aircraft structural design problem.

Advances in Engineering Software, Aug 1, 2000

Of several iterative and direct equation solvers evaluated previously for computations in aeroaco... more Of several iterative and direct equation solvers evaluated previously for computations in aeroacoustics, the most promising was the NASA-developed General-Purpose Solver winner of NASA's 1999 software of the year award. This paper presents detailed, single-processor statistics of the performance of this solver, which has been tailored and optimized for large-scale aeroacoustic computations. The statistics, compiled using an SGI ORIGIN 2000 computer with 12 Gb available memory RAM and eight a vailable processors, are the central processing unit time, RAM requirements, and solution error. The equation solver is capable of solving 10 thousand complex unknowns in as little as 0.01 sec using 0.02 Gb RAM, and 8.4 million complex unknowns in slightly less than 3 hours using all 12 Gb. This latter solution is the largest aeroacoustics problem solved to date with this technique. The study was unable to detect any noticeable error in the solution, since noise levels predicted from these solution vectors are in excellent agreement with the noise levels computed from the exact solution. The equation solver provides a means for obtaining numerical solutions to aeroacoustics problems in three dimensions.

37th Structure, Structural Dynamics and Materials Conference, Apr 15, 1996

This paper describes the performance of a new family of NASA-developed equation solvers used for ... more This paper describes the performance of a new family of NASA-developed equation solvers used for large-scale (i.e. 551,705 equations) structural analysis. To minimize computer time and memory, the solvers are divided by application and matrix characteristics (sparse/dense, real/complex, symmetric/ nonsymmetric, size: in-core/out of core) and exploit the hardware features of current and future computers. In this paper, the equation solvers, which are written in FORTRAN, and are therefore easily transportable, are shown to be faster than specialized computer library routines utilizing assembly code. Twenty NASA structural benchmark models with NASA solver timings reside on World Wide Web with a challenge to beat them.

NASA Tech Briefs, Aug 1, 1979

SPAR (Structural Performance Analysis and Redesign Program), powerful tool for efficiently solvin... more SPAR (Structural Performance Analysis and Redesign Program), powerful tool for efficiently solving finite-element structural analysis problems, has been implemented on minicomputers. System analyzes stress, buckling, vibration, and thermal loads of large linear finite-element structural models.

The analysis and design of complex aerospace structures requires the rapid solution of large syst... more The analysis and design of complex aerospace structures requires the rapid solution of large systems of linear and nonlinear equations, eigenvalue extraction for buckling, vibration and flutter modes, structural optimization and design sensitivity calculation. Computers with multiple processors and vector capabilities can offer substantial computational advantages over traditional scalar computer for these analyses. These computers fall into two categories: shared memory computers and distributed memory computers. This presentation covers general-purpose, highly efficient algorithms for generation/assembly or element matrices, solution of systems of linear and nonlinear equations, eigenvalue and design sensitivity analysis and optimization. All algorithms are coded in FORTRAN for shared memory computers and many are adapted to distributed memory computers. The capability and numerical performance of these algorithms will be addressed.

Current high performance computing (HPC) applications are found in many consumer, industrial and ... more Current high performance computing (HPC) applications are found in many consumer, industrial and research fields. From web searches to auto crash simulations to weather predictions, these applications require large amounts of power by the compute farms or supercomputers ...

On the forefront of recent HPC innovations are Field Programmable Gate Arrays (FPGA), which promi... more On the forefront of recent HPC innovations are Field Programmable Gate Arrays (FPGA), which promise to accelerate calculations by one or more orders of magnitude. The performance of two Cray XD1 systems with Virtex-II Pro 50 and Virtex-4 LX160 FPGAs, were evaluated using a computational biological human genome comparisons program. This paper describes scalable, parallel, FPGA-accelerated results for the FASTA application ssearch34, using the Smith-Waterman algorithm for DNA, RNA and protein sequencing contained in the OpenFPGA benchmark suite. Results indicate typical Cray XD1 FPGA speedups of 50x (Virtex-II Pro 50) and 100x (Virtex-4 LX160) compared to a 2.2 GHz Opteron. Similar speedups are expected for the DRC RPU110-L200 modules (Virtex-4 LX200), which fit in an Opteron socket, and selected by Cray for its XT Supercomputers. The FPGA programming challenges, human genome benchmarking, and data verification of results, are discussed.

Since 1998, no commercially available FPGA has been accompanied by public documentation of its na... more Since 1998, no commercially available FPGA has been accompanied by public documentation of its native machine code (or bitstream) format. Consequently, research in reconfigurable hardware has been confined to areas which are specifically supported by manufacturer-supplied tools. Recently, detailed documentation of the bitstream format for the Atmel FPSLIC series of FPGAs appeared on the usenet group comp.arch.fpga[11]. This information has been used to create abits, a Java library for direct manipulation of FPSLIC bitstreams and partial reconfiguration. The abits library is accompanied by the slipway reference design, a low-cost USB bus-powered board carrying an FPSLIC. This paper describes the abits library and slipway platform, as well as a few applications which they make possible. Both the abits source code and slipway board layout are publicly available under the terms of the BSD license. It is our hope that these tools will enable further research in reconfigurable hardware which would not otherwise be possible.

Electronic Computation, 1979