Configuration Reference: Solver YAML

Table of Contents

• 1. operation_mode
• 2. strategy
• 3. tolerances
• 4. momentum_solver (Solver-Specific Block)
• 5. pressure_solver

For the full commented template, see:

solver.yml controls numerical strategy and solver internals.

1. operation_mode

operation_mode:
  eulerian_field_source: "solve"
  analytical_type: "TGV3D"

Mappings:

• eulerian_field_source -> -euler_field_source (solve, load, analytical)
• analytical_type -> -analytical_type

2. strategy

strategy:
  momentum_solver: "Dual Time Picard RK4"
  central_diff: false

Mappings:

• momentum_solver -> -mom_solver_type (normalized by pic.flow)
• central_diff -> -central

Named solver values are preferred over legacy boolean toggles.

3. tolerances

tolerances:
  max_iterations: 50
  absolute_tol: 1.0e-7
  relative_tol: 1.0e-4
  step_tol: 1.0e-8

Mappings:

• max_iterations -> -mom_max_pseudo_steps
• absolute_tol -> -mom_atol
• relative_tol -> -mom_rtol
• step_tol -> -imp_stol

4. momentum_solver (Solver-Specific Block)

momentum_solver:
  dual_time_picard_rk4:
    max_pseudo_steps: 50
    absolute_tol: 1.0e-8
    relative_tol: 1.0e-5
    step_tol: 1.0e-8
    pseudo_cfl:
      initial: 0.1
      minimum: 0.001
      maximum: 1.0
      growth_factor: 1.0
      reduction_factor: 1.0
    rk4_residual_noise_allowance_factor: 1.05

Mappings include:

• -pseudo_cfl, -min_pseudo_cfl, -max_pseudo_cfl
• -pseudo_cfl_growth_factor, -pseudo_cfl_reduction_factor
• -mom_dt_rk4_residual_norm_noise_allowance_factor

Rule: solver-specific blocks must match selected momentum solver type.

5. pressure_solver

pressure_solver:
  tolerance: 5.0e-9
  multigrid:
    levels: 3
    pre_sweeps: 1
    post_sweeps: 1

Mappings:

• tolerance -> -poisson_tol
• multigrid.levels -> -mg_level
• multigrid.pre_sweeps -> -mg_pre_it
• multigrid.post_sweeps -> -mg_post_it
• multigrid.semi_coarsening.i/j/k -> -mg_i_semi/-mg_j_semi/-mg_k_semi

3. Install PETSc

Advanced escape hatch for raw PETSc flags:

petsc_passthrough_options:
  -ps_ksp_type: "gmres"
  -ps_pc_type: "ilu"

These are passed into PETSc options DB and consumed by runtime calls like KSPSetFromOptions.

9. Next Steps

Proceed to Configuration Reference: Monitor YAML.

For mapping and extension workflows:

• Developer Ingestion Map
• Configuration Extension Playbook
• Momentum Solver Implementations
• Dual-Time Picard RK4 Momentum Solver
• Pressure-Poisson, GMRES, and Multigrid