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Parallel P3M with exact calculation of short range forces

✍ Scribed by T Theuns


Publisher
Elsevier Science
Year
1994
Tongue
English
Weight
895 KB
Volume
78
Category
Article
ISSN
0010-4655

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✦ Synopsis


A P3M (particle-particle, particle-mesh) algorithm to compute the gravitational force on a set of particles is described. The gravitational force is computed using fast Fourier transforms. This leads to an incorrect force when the distance between two particles is of the order of a grid cell. This incorrect force is subtracted exactly from all particles in parallel using convolution with the appropriate Green's function in real space in a time of order NT, irrespective of the degree of clustering of particles. Next, the correct 1 / r 2 force is added for all neighbouring particles in parallel, leading to an accurate algorithm which runs efficiently on a highly parallel computer. A full force calculation for 128k particles on a 128~grid in a mildly clustered situation requires approximately 196 seconds on an 8k Connection Machine 2 with 8MHz clock. This decreases to an estimated 9.8 seconds on a full-sized 64k CM200.


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