标题:Desarrollo de un Conjunto de Rutinas para la Resolución de Sistemas con Matrices Ralas no Simétricas. Comparación de Varios Métodos Iterativos Basados en el de Gradientes Conjugados
其他摘要:Frequently the matrix sustems resulting from the discretization equations arising from Finite Element Method are non symmetric. The direct solvers use a complete factorization of the matrix with a number of operations known in advance for a given matrix size. The iterative methods tend to the solution from an initial guess using a number of operations not known a priori. The performance of these methods is greatly impreved when preconditioners are used. In this work the behaviour of direct and iterative solvers for non symmetric matrices with Gustaffson [1] sparse storage is analysed. The results obtained by means of the iterative methods MCG, BCG, CGS and GMRES, the preconditioner ILE and the pre-preconditioners Blck Diagonal and Diagonal Scaling are shown. The different methods are compared and it is concluded that the CGS method performed best, but GMRES is recommended for very ill-conditioned problems.