Namelist "HomeData_PoissonSolver"

This namelist contains all parameters on the iterative solvers and the nV-cycle multigrid method directly implemented in the code for solving the Poisson's equation (“homemade” development).

These data are taken into account only when the variable “Poisson_NumericalMethod” in the Namelist “Numerical_Methods” is correctly set (see …). Poisson_NumericalMethod= Home-Multigrid-ConstantMatrixCoef Poisson_NumericalMethod= Home-Multigrid-VariableMatrixCoef Not for the release SUNFLUIDH_EDU

Full data set of the namelist

&HomeData_PoissonSolver SolverName="SOR-Redblack-MPI",
Convergence_Criterion= 1.D-15,
Number_max_Grid= 5,
Number_max_Cycle= 10,
Number_Iteration= 0,
Number_Iteration_FineToCoarseGrid= 1,
Number_Iteration_CoarseToFineGrid= 5,
Number_Iteration_CoarsestGrid= 10 ,
Relaxation_Coefficient= 1.7 ,
Off_Set_Poisson_Source_term= .false. /

Following the problem treated, some numerical methods are better adapted than others, this point is precised for each available option. The partial diagonalization method (Poisson_NumericalMethod = “Home-PartialDiagonalization”) used for solving the Poisson equation is only permitted for separable problems. The HYPRE library solvers for solving the Poisson's equation are only available if the HYPRE library has been installed.

Definition of the data set

Number_max_Grid (multigrid method only)

Type : Integer value

Maximum number of grid levels used in the multigrid method.

Number_max_Cycle (multigrid method only)

Type : Integer value

Maximum number of V-cycles permitted in the multigrid method.

Number_Iteration (only if the SOR method is used)

Type : integer value

Number of iterations performed by the SOR method in order to approach the solution on each grid level. This value is the same for any grid level of the Multigrid procedure.

Number_Iteration_FineToCoarseGrid (only if the SOR method is used)

Type : integer value

Number of iterations performed by the SOR solver during the restriction step of each V-cycle of the multigrid procedure. For some problems, the minimization of iterations during the restriction step can improve the time-performance of the code.
BEWARE : this data is enabled only if the variable Number_Iteration= 0 or is removed from the Namelist.

Number_Iteration_CoarsestGrid (only if the SOR method is used)

Type : integer value

Number of iterations performed by the SOR solver on the coarsest grid of each V-cycle of the multigrid procedure.
BEWARE : this data is enabled only if the variable Number_Iteration= 0 or is removed from the Namelist.

Number_Iteration_CoarseToFineFGrid (only if the SOR method is used)

Type : integer value

Number of iterations performed by the SOR solver during the prolongation step of each V-cycle of the multigrid procedure.
BEWARE : this data is enabled only if the variable Number_Iteration= 0 or is removed from the Namelist.

Relaxation_Coefficient (only if the SOR method is used)

Type : real value between one and two

over-relaxation coefficient used in the SOR method.

Convergence_Criterion (only if the SOR method is used)

Type : real value

The nV-cycle procedure of the multigrid method is stopped if the L2-norm of the Poisson equation's residu is lower than the criterion chosen.

Off_Set_Poisson_Source_term

Type : Boolean value. Not for the release SUNFLUIDH_EDU.

The source term is shifted from its averaged value such as its integral value over the domain is zero. This could facilitate the convergence in some particuliar cases. this option must be used with caution. For expert users only.