New Solver (new + solver)

Distribution by Scientific Domains


Selected Abstracts


A frontal solver for the 21st century

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 10 2006
Jennifer A. Scott
Abstract In recent years there have been a number of important developments in frontal algorithms for solving the large sparse linear systems of equations that arise from finite-element problems. We report on the design of a new fully portable and efficient frontal solver for large-scale real and complex unsymmetric linear systems from finite-element problems that incorporates these developments. The new package offers both a flexible reverse communication interface and a simple to use all-in-one interface, which is designed to make the package more accessible to new users. Other key features include automatic element ordering using a state-of-the-art hybrid multilevel spectral algorithm, minimal main memory requirements, the use of high-level BLAS, and facilities to allow the solver to be used as part of a parallel multiple front solver. The performance of the new solver, which is written in Fortran 95, is illustrated using a range of problems from practical applications. The solver is available as package HSL_MA42_ELEMENT within the HSL mathematical software library and, for element problems, supersedes the well-known MA42 package. Copyright 2006 John Wiley & Sons, Ltd. [source]


Toward large scale F.E. computation of hot forging process using iterative solvers, parallel computation and multigrid algorithms

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 5-6 2001
K. Mocellin
Abstract The industrial simulation code Forge3 is devoted to three-dimensional metal forming applications. This finite element software is based on an implicit approach. It is able to carry out the large deformations of viscoplastic incompressible materials with unilateral contact conditions. The finite element discretization is based on a stable mixed velocity,pressure formulation and tetrahedral unstructured meshes. Central to the Newton iterations dealing with the non-linearities, a preconditioned conjugate residual method (PCR) is used. The parallel version of the code uses an SPMD programming model and several results on complex applications have been published. In order to reduce the CPU time computation, a new solver has been developed which is based on multigrid theory. A detailed presentation of the different elements of the method is given: the geometrical approach based on embedded meshes, the direct resolution of the velocity,pressure system, the use of PCR method as an original smoother and for solving the coarse problem, the full multigrid method and the required preconditioning by an incomplete Cholesky factorization for problems with complex contact conditions. By considering different forging cases, the theoretical properties of the multigrid method are numerically verified, optimizations of the solver are presented and finally, the results obtained on several industrial problems are given, showing the efficiency of the new solver that provides speed-up larger than 5. Copyright 2001 John Wiley & Sons, Ltd. [source]


A general Riemann solver for Euler equations

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 11 2008
Hao Wu
Abstract In this paper, we present a general Riemann solver which is applied successfully to compute the Euler equations in fluid dynamics with many complex equations of state (EOS). The solver is based on a splitting method introduced by the authors. We add a linear advection term to the Euler equations in the first step, to make the numerical flux between cells easy to compute. The added linear advection term is thrown off in the second step. It does not need an iterative technique and characteristic wave decomposition for computation. This new solver is designed to permit the construction of high-order approximations to obtain high-order Godunov-type schemes. A number of numerical results show its robustness. Copyright 2007 John Wiley & Sons, Ltd. [source]


An HLLC Riemann solver for relativistic flows , I. Hydrodynamics

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2005
A. Mignone
ABSTRACT We present an extension of the HLLC approximate Riemann solver by Toro, Spruce and Speares to the relativistic equations of fluid dynamics. The solver retains the simplicity of the original two-wave formulation proposed by Harten, Lax and van Leer (HLL) but it restores the missing contact wave in the solution of the Riemann problem. The resulting numerical scheme is computationally efficient, robust and positively conservative. The performance of the new solver is evaluated through numerical testing in one and two dimensions. [source]