Reference / Input deck / solver / solver settings / linear solver options
linear solver options
Linear solver options passed to C++.
flow
settings block·default shown below
PETSc options for the mean flow linear solver
Default
{
"-ksp_min_it": "2",
"-ksp_type": "fgmres",
"-ksp_rtol": "1.0e-3",
"-ksp_converged_reason": "",
}Used inoverset_acoustics
Guidance: Choosing a linear solver →turbulence
settings block·default shown below
PETSc options for the turbulence linear solver
Default
{
"-ksp_min_it": "2",
"-ksp_type": "fgmres",
"-ksp_rtol": "1.0e-5",
"-ksp_converged_reason": "",
}Used inatmosphere
Guidance: Choosing a linear solver →rbf
settings block·default shown below
PETSc options for the RBF linear solver
Default
Guidance: Choosing a linear solver →{
"-ksp_type": "fgmres",
"-ksp_rtol": "1.0e-5",
}double precision
bool·default False
Enable double precision for linear solver
Used inatmosphere
Guidance: Choosing a linear solver →pressure correctionadvancedincompressible only
settings block·default shown below·'pressure correction' only applies when solver.convergence control.scheme.name is 'simple'
PETSc options for the SIMPLE pressure-correction (block-1 Poisson) solver. simpleFoam's p entry: algebraic multigrid, solved to one or two orders
Default
{
"-ksp_min_it": "1",
"-ksp_type": "cg",
"-ksp_rtol": "0.01",
"-ksp_atol": "1.0e-12",
"-ksp_max_it": "100",
"-pc_type": "hypre",
"-pc_hypre_type": "boomeramg",
"-zcfd_pc_reuse_cycles": "20",
"-zcfd_constant_nullspace": "1",
"-ksp_converged_reason": "",
}Used inatmosphere
Guidance: Choosing a linear solver →momentumadvancedincompressible only
settings block·default shown below·'momentum' only applies when solver.convergence control.scheme.name is 'simple'
PETSc options for the SIMPLE momentum predictor (block-3) solver. simpleFoam's U entry: BiCGStab + ILU to relTol 0.1. The under-relaxed momentum matrix is strongly diagonally dominant, so this is a few iterations
Default
{
"-ksp_min_it": "1",
"-ksp_type": "bcgs",
"-ksp_rtol": "0.1",
"-ksp_atol": "1.0e-12",
"-ksp_max_it": "50",
"-pc_type": "bjacobi",
"-sub_pc_type": "ilu",
"-ksp_converged_reason": "",
}Used inatmosphere
Guidance: Choosing a linear solver →