Reordering schemes associated with multicoloring and domain decomposition techniques have been introduced in recent years to obtain parallel and/or vectorized versions of recursive linear solvers such as the Gauss-Sei...
Virtual storage management allows an efficient use of computer memory through the cooperative actions of the computer hardware and the operating system which are completely transparent to application programs. However...
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ISBN:
(纸本)0897913418
Virtual storage management allows an efficient use of computer memory through the cooperative actions of the computer hardware and the operating system which are completely transparent to application programs. However, when program data exceed the available memory space, the program elapsed time may be dominated by the time spent in paging I/O operations. The data transfer rate, as determined by the operating system implementation of demand paging, may be small when compared with the maximum I/O bandwidth that the I/O hardware could ***-ahead is a technique which complements the operating system support of demand paging on virtual storage systems in order to exploit the regularity and predictability which is typical of the data access pattern of large engineering and scientific (E/S) application programs. Application programs may exploit this regularity by using page-ahead to request paging operations from the operating system in anticipation of future needs and take full advantage of the operating systems I/O bandwidth to auxiliary paging store.
Modern supercomputers like CRAY X-MP and ibm 3090 VF achieve their high computing speed by using both vector and parallel hardware. The available multitasking concepts supporting concurrent execution of tasks within a...
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This paper describes a series of experiments performed with block versions of the LU, Cholcsky and QR factorizations using Level 3 BLAS on one processor of the ibm 3090/VF. We show that the LAPACK approach to designin...
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It is shown that the lattice Boltzmann equation (LBE) for a lattice gas provides a viable numerical method for the study of three-dimensional flows in complex geometries. Numerical results for low Reynolds number flow...
We illustrate the basic features of the Lattice Boltzmann Equation (LBE), a new finite-difference scheme that arises from the microdynamics of the Frisch-Hasslacher-Pomeau cellular automaton once, instead of tracking ...
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The mechanisms of two-dimensional turbulence are investigated by means of a very high-resolution lattice-gas simulation. The results from this simulation are quantitatively compared with the direct integration of the ...
The mechanisms of two-dimensional turbulence are investigated by means of a very high-resolution lattice-gas simulation. The results from this simulation are quantitatively compared with the direct integration of the Navier-Stokes equation. The dissipation of the flow simulated by the lattice gas is estimated by a simple scaling argument on the microscopic noisy field of the automaton.
An instruction-level simulator for ibm 3090 with VF (vector facility) has been developed for studying the performance of vector processors and their memory hierarchies. Results of a study of the locality of several la...
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An instruction-level simulator for ibm 3090 with VF (vector facility) has been developed for studying the performance of vector processors and their memory hierarchies. Results of a study of the locality of several large scientific applications are presented. The cache miss ratios of vectorized applications are found to be almost equal to those of their original scalar executions. Moreover, both the spatial and temporal locality of these applications (in scalar and vector executions) are strong enough to show a sufficiently high hit ratio on conventional cache structures.< >
A summary of a numerical study of the stability of modons to topographic perturbation is presented. Previous studies have suggested a monotonic relationship between the horizontal scale of the perturbation and the amp...
A summary of a numerical study of the stability of modons to topographic perturbation is presented. Previous studies have suggested a monotonic relationship between the horizontal scale of the perturbation and the amplitude needed to destroy a modon—as the scale of the perturbation increases the strength needed for destruction decreases. The results presented here show that this relationship does not hold for scales larger than the modon radius. For large‐scale perturbations, the strength needed for destruction again increases. The modon is most stable to perturbations of horizontal scale either much larger or much smaller than the modon radius. Stability graphs are presented for three types of perturbations; ridges, hills, and irregular terrain.
By high-resolution numerical integration of two-dimensional Navier-Stokes equations we show that the turbulent flow at high Reynolds number is dominated by a simple and weakly unstable Hamiltonian system of pointlike ...
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By high-resolution numerical integration of two-dimensional Navier-Stokes equations we show that the turbulent flow at high Reynolds number is dominated by a simple and weakly unstable Hamiltonian system of pointlike vortices. The large instabilities, typical of the turbulent flow, are found uniquely outside vortices, in the wide dissipative region which results to be only a small perturbation of the vortex system. Moreover, the statistical distribution of vortex sizes determines the slope of the energy spectrum, which is steeper than that predicted by phenomenological theories.
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