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On The Efficiency OF Multigrid Solver For Shifted Laplace Equation In A Heteroggenous Medium (Record no. 64759)

MARC details
000 -LEADER
fixed length control field 01988nam a22001457a 4500
082 ## - DEWEY DECIMAL CLASSIFICATION NUMBER
Classification number R/IMS-19
100 ## - MAIN ENTRY--AUTHOR NAME
Personal name Wajid Ahmed
-- 14MSM07
-- Supervisor - Dr. Abdul Hanan Sheikh
245 ## - TITLE STATEMENT
Title On The Efficiency OF Multigrid Solver For Shifted Laplace Equation In A Heteroggenous Medium
260 ## - PUBLICATION, DISTRIBUTION, ETC. (IMPRINT)
Place of publication Nawabshah:
Name of publisher Quest,
Year of publication 2019.
300 ## - PHYSICAL DESCRIPTION
Number of Pages 58p.
500 ## - GENERAL NOTE
General note ABSTRACT<br/><br/><br/>In this thesis, the computational efficiency of multigrid solver is discussed with the comparison of existing solvers such as Jacobi-Gauss (JC), Gauss-Seidel (GS), the latter two met hods Conjugate gradient (CG), Generalized minimum residual (GMRES) wit h and without preconditioner. Helmholtz. equation, problem considered in work is elliptic partial differential equation, which immediately attracts multigrid method . Multigrid is reluctant to perform well in heterogeneous geometries. Further shift in Helmholtz problem allows occurrence of negative eigenvalues, making problem indefinite. These two make multigrid with standard components makes less favorable. In t is work, smoothing parameter in multigrid is tuned to get optimized results in heterogeneous domain . The results are obtained while Inking three different relaxation parameters w = 1, w = 2/3 and w = 1/2 . And different choices of real and imaginary shifts a+bi arc considered for e.g. (0,0),(0,1),(t,1). Results showed<br/>t hat better choice of relaxation parameter in smoother is (J) = 2/3. Also multigrid has better convergence with pure imaginary shift i.e. (0,1) compared to rest of choices of shift.<br/>Pitfalls in multigrid for indefinite case are discussed along with t he reasons. The proposed techniques help to obtain comparably better results than existing solvers. This fact is validated from presented results, where problem with different gird size 11 and different shift "k" are solved using various.above said, solvers.<br/>
700 ## - ADDED ENTRY--PERSONAL NAME
Personal name Department of Mathematics And Statistics
856 ## - ELECTRONIC LOCATION AND ACCESS
Uniform Resource Identifier http://tinyurl.com/43vmky9z
942 ## - ADDED ENTRY ELEMENTS (KOHA)
Koha item type Thesis and Dissertation
Holdings
Withdrawn status Lost status Home library Current library Date acquired Full call number Accession Number Koha item type
    Research Section Research Section 01/07/2019 R/IMS-19 MP/41-458 Thesis and Dissertation

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