High order ILU preconditioners for CFD problems
نویسنده
چکیده
This paper tests a number of ILU-type preconditioners for solving indeenite linear systems which arise from complex applications such as Computational Fluid Dynamics. Both point and block preconditioners are considered. The paper focuses on ILU factorization which can be computed with high accuracy by allowing liberal amounts of ll-in. A number of strategies for enhancing the stability of the factorizations are examined.
منابع مشابه
High-order DNS and LES simulations using an implicit tensor-product discontinuous Galerkin method
This paper describes an efficient tensor-product based preconditioner for the large linear systems arising from the implicit time integration of discontinuous Galerkin (DG) discretizations. A main advantage of the DG method is its potential for high-order accuracy, but the number of degrees of freedom per element scales as p, where p is the polynomial degree and d is the spatial dimension. Stan...
متن کاملNumerical Experiments with Parallel Orderings for Ilu Preconditioners
Incomplete factorization preconditioners such as ILU, ILUT and MILU are well-known robust general-purpose techniques for solving linear systems on serial computers. However, they are difficult to parallelize efficiently. Various techniques have been used to parallelize these preconditioners, such as multicolor orderings and subdomain preconditioning. These techniques may degrade the performance...
متن کاملApproximate Inverse Techniques for Block-Partitioned Matrices
This paper proposes some preconditioning options when the system matrix is in block-partitioned form. This form may arise naturally, for example from the incom-pressible Navier-Stokes equations, or may be imposed after a domain decomposition reordering. Approximate inverse techniques are used to generate sparse approximate solutions whenever these are needed in forming the preconditioner. The s...
متن کاملILU and IUL factorizations obtained from forward and backward factored approximate inverse algorithms
In this paper, an efficient dropping criterion has been used to compute the IUL factorization obtained from Backward Factored APproximate INVerse (BFAPINV) and ILU factorization obtained from Forward Factored APproximate INVerse (FFAPINV) algorithms. We use different drop tolerance parameters to compute the preconditioners. To study the effect of such a dropping on the quality of the ILU ...
متن کاملTowards a Cost-effective Ilu Preconditioner with Higher Level Fills
A recently proposed Minimum Discarded Fill (MDF ) ordering (or pivoting) technique is e ective in nding high quality ILU (`) preconditioners, especially for problems arising from unstructured nite element grids. This algorithm can identify anisotropy in complicated physical structures and orders the unknowns in a \preferred" direction. However, the MDF ordering is costly, when ` increases. In t...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 1996