Efficiency Improvement of Panel Codes

Efficiency Improvement of Panel Codes

Ang, Y.M.E.

Van Gijzen, M.B. (mentor)

Electrical Engineering, Mathematics and Computer Science

Applied mathematics

2015-07-10

Panel codes are used by the Maritime Reseach Institute Natherlands (MARIN) to compute flows around ships and propellers. These codes are based on Boundary Element Methods (BEM). A known drawback of BEM is that it forms dense linear system of equations that have to be solved. By improving the efficiency of the dense linear solver, the computational time required by panel codes can be significantly reduced. Since applications of panel codes in MARIN include automatic optimization, where a large number of hull forms or propeller geometries have to be evaluated, the reduction of computational time is important. Four strategies were explored to improve the performance of the dense linear solver. First, to replace the current GMRES solver with IDR(s). Second, the updating of a fixed size block Jacobi preconditioner into a variable size block Jacobi preconditioner. Third, to use a hierarchical matrix-vector multiplication in the solver instead of dense matrix-vector multiplication. Lastly, to replace the block Jacobi preconditioner with a hierarchical-LU preconditioner. Out of the four strategies, the use of hierarchical-LU preconditioner was found to speed up the dense linear solver substantially, especially for large systems. The use of IDR(s) instead of GMRES is also recommended as it removes the problems introduced by the need to restart. This report discusses the theory, implementation and test results obtained from the four strategies aforementioned. As a result of this project, the use of IDR(s) combined with hierarchical-LU preconditioner is recommended to be implemented in the panel codes.

Hierarchical Matrices
Boundary Element Method
Panel Codes
Dense linear solver

http://resolver.tudelft.nl/uuid:75b3228a-f360-4d2e-baed-139ee767c049

Student theses

master thesis

(c) 2015 Ang, Y.M.E.