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Computer Architectures (computer + architecture)
Selected AbstractsSIMDE: An educational simulator of ILP architectures with dynamic and static schedulingCOMPUTER APPLICATIONS IN ENGINEERING EDUCATION, Issue 3 2007I. Castilla Abstract This article presents SIMDE, a cycle-by-cycle simulator to support teaching of Instruction-Level Parallelism (ILP) architectures. The simulator covers dynamic and static instruction scheduling by using a shared structure for both approaches. Dynamic scheduling is illustrated by means of a simple superscalar processor based on Tomasulo's algorithm. A basic Very Long Instruction Word (VLIW) processor has been designed for static scheduling. The simulator is intended as an aid-tool for teaching theoretical contents in Computer Architecture and Organization courses. The students are provided with an easy-to-use common environment to perform different simulations and comparisons between superscalar and VLIW processors. Furthermore, the simulator has been tested by students in a Computer Architecture course in order to assess its real usefulness. © 2007 Wiley Periodicals, Inc. Comput Appl Eng Educ 14: 226,239, 2007; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20154 [source] Circuits, computers, and beyond Boolean logic,INTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 5-6 2007Tamás Roska Abstract Historically, the invention of the stored programmable computer architecture, introduced by John Von Neumann, was also influenced by electrical circuit implementation aspects, as well as tied to fundamental insight of logic reasoning. It can also be considered as a mind-inspired machine. Since then, the implementation of logic gates, control and memories has developed independently of the architecture. The Cellular Wave Computer architecture (IEEE Trans. Circuits Syst. II 1993; 40:163,173; Electron. Lett. 2007; 43:427,449; J. Circuits Syst. Comput. 2003; 5(2):539,562) as a spatial,temporal universal machine on flows has also been influenced by circuit aspects of very large-scale integration (VLSI) technology, as well as some motivating living neural circuits, via the cellular nonlinear (neural) network (CNN). It might be considered as a brain-inspired machine. In this paper, after summarizing the main properties of the Cellular Wave Computer, we highlight a few basic properties of this new kind of computer and computing. In particular, phenomena related to (i) the one-pass solution of a set of implicit equations due to real-time spatial array feedback, (ii) the true random signal array generation via the insertion of the continuous physical noise signals, (iii) the finite synchrony radius due to the functional delay of wires, as well as to (iv) biology relevance. We also show that the Cellular Wave Computer is performing spatial,temporal inference that goes beyond Boolean logic, a characteristic of living neural circuits. Copyright © 2007 John Wiley & Sons, Ltd. [source] DEA network computing in multi-stage parallel processesINTERNATIONAL TRANSACTIONS IN OPERATIONAL RESEARCH, Issue 3 2003Toshiyuki Sueyoshi DEA (Data Envelopment Analysis) is a managerial method that has been widely used for performance analysis in various public and private sectors. To deal with large-scale DEA problems, this research proposes the architecture of DEA network computing (LAN: Local Area Network) that is designed to coordinate a simultaneous use of multiple personal computers. An important feature of the proposed DEA computer architecture is that it is computationally structured in multi-stage parallel processes to enhance its algorithmic efficiency. The performance of the proposed network computing approach is tested and examined in a large simulation study. [source] A cache-efficient implementation of the lattice Boltzmann method for the two-dimensional diffusion equationCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 14 2004A. C. Velivelli Abstract The lattice Boltzmann method is an important technique for the numerical solution of partial differential equations because it has nearly ideal scalability on parallel computers for many applications. However, to achieve the scalability and speed potential of the lattice Boltzmann technique, the issues of data reusability in cache-based computer architectures must be addressed. Utilizing the two-dimensional diffusion equation, , this paper examines cache optimization for the lattice Boltzmann method in both serial and parallel implementations. In this study, speedups due to cache optimization were found to be 1.9,2.5 for the serial implementation and 3.6,3.8 for the parallel case in which the domain decomposition was optimized for stride-one access. In the parallel non-cached implementation, the method of domain decomposition (horizontal or vertical) used for parallelization did not significantly affect the compute time. In contrast, the cache-based implementation of the lattice Boltzmann method was significantly faster when the domain decomposition was optimized for stride-one access. Additionally, the cache-optimized lattice Boltzmann method in which the domain decomposition was optimized for stride-one access displayed superlinear scalability on all problem sizes as the number of processors was increased. Copyright © 2004 John Wiley & Sons, Ltd. [source] A block-implicit numerical procedure for simulation of buoyant swirling flows in a model furnaceINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 3 2003Marcelo J. S. de Lemos Abstract This work reports numerical results for the case of incompressible laminar heated flow with a swirl in a vertical cylindrical chamber. Computations are obtained with a point-wise block-implicit scheme. Flow governing equations are written in terms of the so-called primitive variables and are recast into a general form. The discretized momentum equations are applied to each cell face and then, together with the mass-continuity, tangential velocity and energy equations, are solved directly in each computational node. The effects of Rayleigh, Reynolds and Swirl numbers on the temperature field are discussed. Flow pattern and scalar residual history are reported. Further, it is expected that more advanced parallel computer architectures can benefit from the error smoothing operator here described. Copyright © 2003 John Wiley & Sons, Ltd. [source] Ab-initio simulations of materials using VASP: Density-functional theory and beyondJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 13 2008Jürgen Hafner Abstract During the past decade, computer simulations based on a quantum-mechanical description of the interactions between electrons and between electrons and atomic nuclei have developed an increasingly important impact on solid-state physics and chemistry and on materials science,promoting not only a deeper understanding, but also the possibility to contribute significantly to materials design for future technologies. This development is based on two important columns: (i) The improved description of electronic many-body effects within density-functional theory (DFT) and the upcoming post-DFT methods. (ii) The implementation of the new functionals and many-body techniques within highly efficient, stable, and versatile computer codes, which allow to exploit the potential of modern computer architectures. In this review, I discuss the implementation of various DFT functionals [local-density approximation (LDA), generalized gradient approximation (GGA), meta-GGA, hybrid functional mixing DFT, and exact (Hartree-Fock) exchange] and post-DFT approaches [DFT + U for strong electronic correlations in narrow bands, many-body perturbation theory (GW) for quasiparticle spectra, dynamical correlation effects via the adiabatic-connection fluctuation-dissipation theorem (AC-FDT)] in the Vienna ab initio simulation package VASP. VASP is a plane-wave all-electron code using the projector-augmented wave method to describe the electron-core interaction. The code uses fast iterative techniques for the diagonalization of the DFT Hamiltonian and allows to perform total-energy calculations and structural optimizations for systems with thousands of atoms and ab initio molecular dynamics simulations for ensembles with a few hundred atoms extending over several tens of ps. Applications in many different areas (structure and phase stability, mechanical and dynamical properties, liquids, glasses and quasicrystals, magnetism and magnetic nanostructures, semiconductors and insulators, surfaces, interfaces and thin films, chemical reactions, and catalysis) are reviewed. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2008 [source] | ||||||||||