M. S. Warren, P. J. Quinn, J. K. Salmon, and W. H. Zurek, "Dark halos formed via dissipationless collapse: I. Shapes and alignment of angular momentum," Ap. J., vol. 399, pp. 405-- 425, 1992.  Home/Search   Document Not in Database   Summary   Related Articles   Check

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M. S. Warren, P. J. Quinn, J. K. Salmon, and W. H. Zurek, "Dark halos formed via dissipationless collapse: I. Shapes and alignment of angular momentum," Ap. J., vol. 399, pp. 405-- 425, 1992.

....methods do not contribute significantly to the total solution error. This is because the force errors are exceeded by or are comparable to the time integration error and discretization error. Using a generic design, we have implemented a variety of modules to solve problems in galactic dynamics [8] and cosmology [9] as well as fluiddynamical problems using smoothed particle hydrodynamics [10] a vortex particle method [11] and boundary integral methods [12] 3.1 The Hashed Oct Tree Library Our parallel N body code has been evolving for over a decade on many platforms. We began with an ....

....smoothed particle hydrodynamics [10] a vortex particle method [11] and boundary integral methods [12] 3.1 The Hashed Oct Tree Library Our parallel N body code has been evolving for over a decade on many platforms. We began with an Intel ipsc 860, Ncube machines, and the Caltech JPL Mark III [13, 8]. This original version of the code was abandoned after it won a Gordon Bell Performance Prize in 1992 [14] due to various flaws inherent in the code, which was ported from a serial version. A new version of the code was initially described in [15] The basic algorithm may be divided into ....

M. S. Warren, P. J. Quinn, J. K. Salmon, and W. H. Zurek, "Dark halos formed via dissipationless collapse: I. Shapes and alignment of angular momentum," Ap. J., vol. 399, pp. 405--425, 1992.

....cluster simulation with 1.1 million particles computed using local expansions. This simulation of 2700 timesteps was completed in about 15 hours on 128 processors of an Intel Paragon. Additional applications of earlier versions of our treecode to large astrophysical N body problems may be found in [22, 23] and [24] 9.1 The Vortex Particle Method The vorticity equation ( r Theta u, and hence r Delta = 0) for an incompressible fluid (r Delta u = 0) is obtained from taking the curl of the momentum equation: D Dt = ru) Delta r 2 ; 33) where Df Dt = f t (u Delta r) ....

....10 Conclusion Particle methods are useful for studying an enormous variety of systems. Hockney and Eastwood [28] discuss applications in plasma physics, device physics, astrophysics and material science. Our code has allowed us to make significant progress in the study of galaxy dynamics [22] and cosmology [23] In addition, we note applications in molecular dynamics [29] computational fluid dynamics [30, 31] and partial differential equations relevant to biology [32] Fast multipole methods have been used to address two dimensional problems in potential flows [33] and ....

M. S. Warren, P. J. Quinn, J. K. Salmon, and W. H. Zurek, "Dark halos formed via dissipationless collapse: I. Shapes and alignment of angular momentum," Ap. J., vol. 399, pp. 405--425, 1992. 24

....if necessary, to ensure that the particle representation of the vorticity field remains a good representation of the true divergence free vorticity field in long time computations. 1 Introduction A fast oct tree code, originally developed for three dimensional N body gravitational problems [26 28, 32 34] has been modified into (1) a fast N vortex code for viscous and inviscid vortex flow computations [29] using the regularized vortex particle method ( vortex element method, VEM) 19, 20, 25, 36 40] combined with the particle strength exchange scheme for viscous diffusion [4, 21] and (2) a fast ....

Warren, M.S., Quinn, P.J., Salmon, J.K. and Zurek, W.H., "Dark Halos Formed via Dissipationless Collapse: I. Shapes and Alignment of Angular Momentum," Ap. J., 399, pp. 405--425, 1992.

....the parent cell, and those within the unshaded region would interact with even smaller cells inside the daughter cell. 3 Computational Approach Parallel treecodes for distributed memory machines are discussed in [9, 10] and their application to the analysis of galaxy formation may be found in [11, 12]. Further analysis and extensions of the computational methods may be found in [13, 14, 15] The MAC described above is problematical for these previous methods because the parallel algorithm requires determination of locally essential data before the tree traversal begins. With the data dependent ....

M. S. Warren, P. J. Quinn, J. K. Salmon, and W. H. Zurek, "Dark halos formed via dissipationless collapse: I. Shapes and alignment of angular momentum," Ap. J., vol. 399, pp. 405--425, 1992.

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