nl_keigen.cc

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#include "nl_keigen.h"
 
#include "ChiObjectFactory.h"
#include "chi_log.h"
 
#include "A_LBSSolver/IterativeMethods/poweriteration_keigen.h"
 
namespace lbs
{
 
RegisterChiObject(lbs, XXNonLinearKEigen);
 
chi::InputParameters XXNonLinearKEigen::GetInputParameters()
{
  chi::InputParameters params = chi_physics::Solver::GetInputParameters();
 
  params.SetGeneralDescription(
    "Generalized implementation of a non-linear k-Eigenvalue solver");
  params.SetDocGroup("LBSExecutors");
 
  params.ChangeExistingParamToOptional("name", "XXPowerIterationKEigen");
 
  params.AddRequiredParameter<size_t>("lbs_solver_handle",
                                      "Handle to an existing lbs solver");
 
  params.AddOptionalParameter(
    "nl_abs_tol", 1.0e-8, "Non-linear absolute tolerance");
  params.AddOptionalParameter(
    "nl_rel_tol", 1.0e-8, "Non-linear relative tolerance");
  params.AddOptionalParameter(
    "nl_sol_tol", 1.0e-50, "Non-linear solution tolerance");
  params.AddOptionalParameter(
    "nl_max_its", 50, "Non-linear maximum iterations");
 
  params.AddOptionalParameter("l_abs_tol", 1.0e-8, "Linear absolute tolerance");
  params.AddOptionalParameter("l_rel_tol", 1.0e-8, "Linear relative tolerance");
  params.AddOptionalParameter(
    "l_div_tol", 1.0e6, "Linear divergence tolerance");
  params.AddOptionalParameter("l_max_its", 50, "Linear maximum iterations");
  params.AddOptionalParameter(
    "l_gmres_restart_intvl", 30, "GMRes restart interval");
  params.AddOptionalParameter(
    "l_gmres_breakdown_tol", 1.0e6, "GMRes breakdown tolerance");
 
  params.AddOptionalParameter(
    "reinit_phi_1", true, "If true, reinitializes scalar phi fluxes to 1");
 
  params.AddOptionalParameter("num_free_power_iterations",
                              0,
                              "The number of free power iterations to execute "
                              "before entering the non-linear algorithm");
 
  return params;
}
 
XXNonLinearKEigen::XXNonLinearKEigen(const chi::InputParameters& params)
  : chi_physics::Solver(params),
    lbs_solver_(Chi::GetStackItem<LBSSolver>(
      Chi::object_stack, params.GetParamValue<size_t>("lbs_solver_handle"))),
    nl_context_(std::make_shared<NLKEigenAGSContext<Vec, SNES>>(lbs_solver_)),
    nl_solver_(nl_context_),
    reinit_phi_1_(params.GetParamValue<bool>("reinit_phi_1")),
    num_free_power_its_(params.GetParamValue<int>("num_free_power_iterations"))
{
  auto& tolerances = nl_solver_.ToleranceOptions();
 
  tolerances.nl_abs_tol_ = params.GetParamValue<double>("nl_abs_tol");
  tolerances.nl_rel_tol_ = params.GetParamValue<double>("nl_rel_tol");
  tolerances.nl_sol_tol_ = params.GetParamValue<double>("nl_sol_tol");
  tolerances.nl_max_its_ = params.GetParamValue<int>("nl_max_its");
 
  tolerances.l_rel_tol_ = params.GetParamValue<double>("l_rel_tol");
  tolerances.l_abs_tol_ = params.GetParamValue<double>("l_abs_tol");
  tolerances.l_div_tol_ = params.GetParamValue<double>("l_div_tol");
  tolerances.l_max_its_ = params.GetParamValue<int>("l_max_its");
  tolerances.l_gmres_restart_intvl_ =
    params.GetParamValue<int>("l_gmres_restart_intvl");
  tolerances.l_gmres_breakdown_tol_ =
    params.GetParamValue<double>("l_gmres_breakdown_tol");
}
 
void XXNonLinearKEigen::Initialize() { lbs_solver_.Initialize(); }
 
void XXNonLinearKEigen::Execute()
{
  if (reinit_phi_1_)
    lbs_solver_.SetPhiVectorScalarValues(lbs_solver_.PhiOldLocal(), 1.0);
 
  if (num_free_power_its_ > 0)
  {
    double k_eff = 1.0;
    PowerIterationKEigen(lbs_solver_,
                         nl_solver_.ToleranceOptions().nl_abs_tol_,
                         num_free_power_its_,
                         k_eff);
  }
 
  nl_solver_.Setup();
  nl_solver_.Solve();
 
  if (lbs_solver_.Options().use_precursors)
  {
    lbs_solver_.ComputePrecursors();
    chi_math::Scale(lbs_solver_.PrecursorsNewLocal(),
                    1.0 / nl_context_->kresid_func_context_.k_eff);
  }
 
  lbs_solver_.UpdateFieldFunctions();
 
  Chi::log.Log()
    << "LinearBoltzmann::KEigenvalueSolver execution completed\n\n";
}
 
} // namespace lbs