TY  - GEN
Y1  - 2009///
AV  - public
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/10188/
TI  - Astro-GRIPS, the General Relativistic Implicit Parallel Solver for Astrophysical Fluid Flows
KW  - implizite Verfahren 
KW  -  Simulationsprogramm hydrodynamics 
KW  -  gravitation 
KW  -  general relativity 
KW  -  implicit methods 
KW  -  simulation code 
ID  - heidok10188
N2  - In this work the development of the simulation code Astro-GRIPS, the General Relativistic Implicit Parallel Solver, is performed, which solves the three-dimensional axi-symmetric general relativistic hydrodynamic Euler or Navier-Stokes equations under the assumption of a fixed background metric of a Schwarzschild or Kerr black hole using time-implicit methods. It is an almost total re-write of an old spaghetti-code like serial Fortran 77 simulation program. By modernization and optimization it is now a modern, well structured, user-friendly, flexible and extensible simulation program written in Fortran 90/95. The finite volume discretization ensures conservation and the defect-correction iteration strategy is used to resolve the non-linearities of the equations. One can use a variety of solution procedures that range from purely explicit up to fully implicit schemes with up to third order spatial and second order temporal accuracy. The large sparse linear equation systems used for the implicit methods can be solved by the Black-White Line-Gauß-Seidel relaxation method (BW-LGS), the Approximate Factorization Method (AFM) or by Krylov Subspace Iterative methods like GMRES. The optimal solution method and the coupling of equations is problem-dependent. Optimizations in the matrix construction, the MPI-Parallelization for distributed memory machines and several Newtonian and relativistic tests were conducted successfully. 
A1  - Keil, Bernhard Wolfram
ER  -