A Multi Level Direct Sub-Structuring Multi-Frontal Parallel Solver for the hp-Finite Element Method
A Multi Level Direct Sub-Structuring Multi-Frontal Parallel Solver for the hp-Finite Element Method
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发表时间:
2007
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通讯作者:
M. Paszyński;David Pardo;C. Torres‐Verdín;L. Demkowicz;V. Calo
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作者:
M. Paszyński;David Pardo;C. Torres‐Verdín;L. Demkowicz;V. Calo
The paper presents a new parallel direct solver for hp refined meshes, utilized by a 2D hp adaptive Finite Element Method (FEM) to solve 3D Direct Curr ent (DC) borehole resistivity measurement problems. The self-adaptive hp FEM generates in a fully automatic mode a sequence of hp meshes delivering exponential convergence of the error wit h respect to the number of degrees of freedom (d.o.f.) as well as the CPU time. Th new parallel solver works on the three-level elimination tree, distributed into proc essors: (1) the refinement tree growing from initial mesh elements, (2) the initial mesh element tree, and (3) the sub-domain tree resulting from the domain decomposition. The solver comput es Schur complements at every tree node, by performing partial forward elimination, leav ing untouched partially assembled (or unassembled) d.o.f. The Schur complements are stored at tree nodes, and can be re-utilized when solving subsequent hp meshes (produced by the self-adaptive strategy), when thes e hp meshes contain elements that have not been refined, as it typi call occurs in real applications. Execution time and memory usage of the solver are compared ag ainst those delivered by the parallel MUltifrontl Massively Parallel sparse direct Sol ver (MUMPS) with (1) centralized entries submitted from the host processor, (2) distributed en tries submitted from sub-domains, and (3) the MUMPS based direct sub-structuring method when t parallel MUMPS solver with distributed entries is utilized to solve the interface problem.