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Redundant Ghost Nodes in Jacobi. Overview of Memory Hierarchy Optimization Can be used on unstructured meshes Size of ghost region (and redundant computation) depends on network/memory speed vs. computation. To compute green. Copy yellow. Compute blue.
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Redundant Ghost Nodes in Jacobi • Overview of Memory Hierarchy Optimization • Can be used on unstructured meshes • Size of ghost region (and redundant computation) depends on network/memory speed vs. computation To compute green Copy yellow Compute blue
Convergence of Nearest Neighbor Methods • Jacobi’s method involves nearest neighbor computation on nxn grid (N = n2) • So it takes O(n) = O(sqrt(N)) iterations for information to propagate • E.g., consider a rhs (b) that is 0, except the center is 1 • The exact solution looks like: Even in the best case, any nearest neighbor computation will take n/2 steps to propagate on an nxn grid