libMesh::EulerSolver Class Reference

#include <euler_solver.h>

Inheritance diagram for libMesh::EulerSolver:

[legend]

List of all members.

Public Types
typedef UnsteadySolver	Parent
typedef DifferentiableSystem	sys_type
Public Member Functions
	EulerSolver (sys_type &s)
virtual	~EulerSolver ()
virtual Real	error_order () const
virtual bool	element_residual (bool request_jacobian, DiffContext &)
virtual bool	side_residual (bool request_jacobian, DiffContext &)
virtual void	init ()
virtual void	init_data ()
virtual void	reinit ()
virtual void	solve ()
virtual void	advance_timestep ()
virtual void	adjoint_advance_timestep ()
virtual void	retrieve_timestep ()
Number	old_nonlinear_solution (const dof_id_type global_dof_number) const
virtual Real	du (const SystemNorm &norm) const
virtual bool	is_steady () const
virtual void	before_timestep ()
const sys_type &	system () const
sys_type &	system ()
virtual AutoPtr< DiffSolver > &	diff_solver ()
virtual AutoPtr< LinearSolver < Number > > &	linear_solver ()
void	set_solution_history (const SolutionHistory &_solution_history)
bool	is_adjoint () const
void	set_is_adjoint (bool _is_adjoint_value)
Static Public Member Functions
static std::string	get_info ()
static void	print_info (std::ostream &out=libMesh::out)
static unsigned int	n_objects ()
static void	enable_print_counter_info ()
static void	disable_print_counter_info ()
Public Attributes
Real	theta
AutoPtr< NumericVector< Number > >	old_local_nonlinear_solution
bool	quiet
unsigned int	reduce_deltat_on_diffsolver_failure
Protected Types
typedef std::map< std::string, std::pair< unsigned int, unsigned int > >	Counts
Protected Member Functions
void	increment_constructor_count (const std::string &name)
void	increment_destructor_count (const std::string &name)
Protected Attributes
bool	first_solve
bool	first_adjoint_step
AutoPtr< DiffSolver >	_diff_solver
AutoPtr< LinearSolver< Number > >	_linear_solver
sys_type &	_system
AutoPtr< SolutionHistory >	solution_history
Static Protected Attributes
static Counts	_counts
static Threads::atomic < unsigned int >	_n_objects
static Threads::spin_mutex	_mutex
static bool	_enable_print_counter = true

---

Detailed Description

This class defines a theta-method Euler (defaulting to Backward Euler with theta = 1.0) solver to handle time integration of DifferentiableSystems.

This class is part of the new DifferentiableSystem framework, which is still experimental. Users of this framework should beware of bugs and future API changes.

Author:

Roy H. Stogner 2006

Definition at line 45 of file euler_solver.h.

---

Member Typedef Documentation

typedef std::map<std::string, std::pair<unsigned int, unsigned int> > libMesh::ReferenceCounter::Counts [protected, inherited]

Data structure to log the information. The log is identified by the class name.

Definition at line 113 of file reference_counter.h.

typedef UnsteadySolver libMesh::EulerSolver::Parent

The parent class

Definition at line 51 of file euler_solver.h.

typedef DifferentiableSystem libMesh::TimeSolver::sys_type [inherited]

The type of system

Reimplemented in libMesh::EigenTimeSolver, and libMesh::SteadySolver.

Definition at line 66 of file time_solver.h.

---

Constructor & Destructor Documentation

libMesh::EulerSolver::EulerSolver

(

sys_type &

s

)

[explicit]

Constructor. Requires a reference to the system to be solved.

Definition at line 27 of file euler_solver.C.

 : UnsteadySolver(s), theta(1.)
{
}

libMesh::EulerSolver::~EulerSolver

(

)

[virtual]

Destructor.

Definition at line 34 of file euler_solver.C.

{
}

---

Member Function Documentation

void libMesh::UnsteadySolver::adjoint_advance_timestep

(

)

[virtual, inherited]

This method advances the adjoint solution to the previous timestep, after an adjoint_solve() has been performed. This will be done before every UnsteadySolver::adjoint_solve().

Reimplemented from libMesh::TimeSolver.

Definition at line 169 of file unsteady_solver.C.

References libMesh::TimeSolver::_system, libMesh::DifferentiableSystem::deltat, libMesh::UnsteadySolver::first_adjoint_step, libMesh::System::get_dof_map(), libMesh::DofMap::get_send_list(), libMesh::System::get_vector(), libMesh::NumericVector< T >::localize(), libMesh::UnsteadySolver::old_local_nonlinear_solution, libMesh::TimeSolver::solution_history, and libMesh::System::time.

{
  // On the first call of this function, we dont save the adjoint solution or
  // decrement the time, we just call the retrieve function below
  if(!first_adjoint_step)
    {
      // Call the store function to store the last adjoint before decrementing the time
      solution_history->store();
      // Decrement the system time
      _system.time -= _system.deltat;
    }
  else
    {
      first_adjoint_step = false;
    }

  // Retrieve the primal solution vectors at this time using the
  // solution_history object
  solution_history->retrieve();

  // Dont forget to localize the old_nonlinear_solution !
  _system.get_vector("_old_nonlinear_solution").localize
    (*old_local_nonlinear_solution,
     _system.get_dof_map().get_send_list());
}

void libMesh::UnsteadySolver::advance_timestep

(

)

[virtual, inherited]

This method advances the solution to the next timestep, after a solve() has been performed. Often this will be done after every UnsteadySolver::solve(), but adaptive mesh refinement and/or adaptive time step selection may require some solve() steps to be repeated.

Reimplemented from libMesh::TimeSolver.

Reimplemented in libMesh::AdaptiveTimeSolver.

Definition at line 143 of file unsteady_solver.C.

References libMesh::TimeSolver::_system, libMesh::DifferentiableSystem::deltat, libMesh::UnsteadySolver::first_solve, libMesh::System::get_dof_map(), libMesh::DofMap::get_send_list(), libMesh::System::get_vector(), libMesh::NumericVector< T >::localize(), libMesh::UnsteadySolver::old_local_nonlinear_solution, libMesh::System::solution, libMesh::TimeSolver::solution_history, and libMesh::System::time.

Referenced by libMesh::UnsteadySolver::solve().

{
  if (!first_solve)
    {
      // Store the solution, does nothing by default
      // User has to attach appropriate solution_history object for this to
      // actually store anything anywhere
      solution_history->store();

      _system.time += _system.deltat;
    }

  NumericVector<Number> &old_nonlinear_soln =
  _system.get_vector("_old_nonlinear_solution");
  NumericVector<Number> &nonlinear_solution =
    *(_system.solution);

  old_nonlinear_soln = nonlinear_solution;

  old_nonlinear_soln.localize
    (*old_local_nonlinear_solution,
     _system.get_dof_map().get_send_list());
}

virtual void libMesh::TimeSolver::before_timestep

(

)

[inline, virtual, inherited]

This method is for subclasses or users to override to do arbitrary processing between timesteps

Definition at line 152 of file time_solver.h.

{}

virtual AutoPtr<DiffSolver>& libMesh::TimeSolver::diff_solver

(

)

[inline, virtual, inherited]

An implicit linear or nonlinear solver to use at each timestep.

Reimplemented in libMesh::AdaptiveTimeSolver.

Definition at line 167 of file time_solver.h.

References libMesh::TimeSolver::_diff_solver.

{ return _diff_solver; }

void libMesh::ReferenceCounter::disable_print_counter_info

(

)

[static, inherited]

Definition at line 106 of file reference_counter.C.

References libMesh::ReferenceCounter::_enable_print_counter.

{
  _enable_print_counter = false;
  return;
}

Real libMesh::UnsteadySolver::du

(

const SystemNorm &

norm

)

const [virtual, inherited]

Computes the size of ||u^{n+1} - u^{n}|| in some norm.

Note that, while you can always call this function, its result may or may not be very meaningful. For example, if you call this function right after calling advance_timestep() then you'll get a result of zero since old_nonlinear_solution is set equal to nonlinear_solution in this function.

Implements libMesh::TimeSolver.

Definition at line 218 of file unsteady_solver.C.

References libMesh::TimeSolver::_system, libMesh::System::calculate_norm(), libMesh::System::get_vector(), and libMesh::System::solution.

{

  AutoPtr<NumericVector<Number> > solution_copy =
    _system.solution->clone();

  solution_copy->add(-1., _system.get_vector("_old_nonlinear_solution"));

  solution_copy->close();

  return _system.calculate_norm(*solution_copy, norm);
}

bool libMesh::EulerSolver::element_residual	(	bool	request_jacobian,
		DiffContext &	context
	)			[virtual]

This method uses the DifferentiableSystem's element_time_derivative() and element_constraint() to build a full residual on an element. What combination it uses will depend on theta.

Implements libMesh::TimeSolver.

Definition at line 50 of file euler_solver.C.

References libMesh::TimeSolver::_system, libMesh::DenseVector< T >::add(), libMesh::DifferentiableSystem::deltat, libMesh::DiffContext::dof_indices, libMesh::DiffContext::elem_fixed_solution, libMesh::DiffContext::elem_jacobian, libMesh::DiffContext::elem_reinit(), libMesh::DiffContext::elem_residual, libMesh::DiffContext::elem_solution, libMesh::DiffContext::elem_solution_derivative, libMesh::DifferentiablePhysics::element_constraint(), libMesh::DifferentiablePhysics::element_time_derivative(), libMesh::DifferentiablePhysics::eulerian_residual(), libMesh::DiffContext::fixed_solution_derivative, libMesh::DifferentiablePhysics::mass_residual(), libMesh::UnsteadySolver::old_nonlinear_solution(), libMesh::DenseVector< T >::size(), libMesh::DenseMatrix< T >::swap(), libMesh::DenseVector< T >::swap(), theta, libMesh::System::use_fixed_solution, libMesh::DenseVector< T >::zero(), and libMesh::DenseMatrix< T >::zero().

{
  unsigned int n_dofs = context.elem_solution.size();

  // Local nonlinear solution at old timestep
  DenseVector<Number> old_elem_solution(n_dofs);
  for (unsigned int i=0; i != n_dofs; ++i)
    old_elem_solution(i) =
      old_nonlinear_solution(context.dof_indices[i]);

  // Local nonlinear solution at time t_theta
  DenseVector<Number> theta_solution(context.elem_solution);
  theta_solution *= theta;
  theta_solution.add(1. - theta, old_elem_solution);

  // Technically the elem_solution_derivative is either theta
  // or -1.0 in this implementation, but we scale the former part
  // ourselves
  context.elem_solution_derivative = 1.0;

// Technically the fixed_solution_derivative is always theta,
// but we're scaling a whole jacobian by theta after these first
// evaluations
  context.fixed_solution_derivative = 1.0;

  // If a fixed solution is requested, we'll use theta_solution
  if (_system.use_fixed_solution)
    context.elem_fixed_solution = theta_solution;

  // Move theta_->elem_, elem_->theta_
  context.elem_solution.swap(theta_solution);

  // Move the mesh into place first if necessary
  context.elem_reinit(theta);

  // We're going to compute just the change in elem_residual
  // (and possibly elem_jacobian), then add back the old values
  DenseVector<Number> old_elem_residual(context.elem_residual);
  DenseMatrix<Number> old_elem_jacobian;
  if (request_jacobian)
    {
      old_elem_jacobian = context.elem_jacobian;
      context.elem_jacobian.zero();
    }
  context.elem_residual.zero();

  // Get the time derivative at t_theta
  bool jacobian_computed =
    _system.element_time_derivative(request_jacobian, context);

  // For a moving mesh problem we may need the pseudoconvection term too
  jacobian_computed =
    _system.eulerian_residual(jacobian_computed, context) && jacobian_computed;

  // Scale the time-dependent residual and jacobian correctly
  context.elem_residual *= _system.deltat;
  if (jacobian_computed)
    context.elem_jacobian *= (theta * _system.deltat);

  // The fixed_solution_derivative is always theta,
  // and now we're done scaling jacobians
  context.fixed_solution_derivative = theta;

  // We evaluate mass_residual with the change in solution
  // to get the mass matrix, reusing old_elem_solution to hold that
  // delta_solution.  We're solving dt*F(u) - du = 0, so our
  // delta_solution is old_solution - new_solution.
  // We're still keeping elem_solution in theta_solution for now
  old_elem_solution -= theta_solution;

  // Move old_->elem_, theta_->old_
  context.elem_solution.swap(old_elem_solution);

  // We do a trick here to avoid using a non-1
  // elem_solution_derivative:
  context.elem_jacobian *= -1.0;
  jacobian_computed = _system.mass_residual(jacobian_computed, context) &&
    jacobian_computed;
  context.elem_jacobian *= -1.0;

  // Move elem_->elem_, old_->theta_
  context.elem_solution.swap(theta_solution);

  // Restore the elem position if necessary
  context.elem_reinit(1.);

  // Add the constraint term
  jacobian_computed = _system.element_constraint(jacobian_computed, context) &&
    jacobian_computed;

  // Add back the old residual and jacobian
  context.elem_residual += old_elem_residual;
  if (request_jacobian)
    {
      if (jacobian_computed)
        context.elem_jacobian += old_elem_jacobian;
      else
        context.elem_jacobian.swap(old_elem_jacobian);
    }

  return jacobian_computed;
}

void libMesh::ReferenceCounter::enable_print_counter_info

(

)

[static, inherited]

Methods to enable/disable the reference counter output from print_info()

Definition at line 100 of file reference_counter.C.

References libMesh::ReferenceCounter::_enable_print_counter.

{
  _enable_print_counter = true;
  return;
}

Real libMesh::EulerSolver::error_order

(

)

const [virtual]

Error convergence order: 2 for Crank-Nicolson, 1 otherwise

Implements libMesh::UnsteadySolver.

Definition at line 40 of file euler_solver.C.

References theta.

{
  if (theta == 0.5)
    return 2.;
  return 1.;
}

std::string libMesh::ReferenceCounter::get_info

(

)

[static, inherited]

Gets a string containing the reference information.

Definition at line 47 of file reference_counter.C.

References libMesh::ReferenceCounter::_counts, and libMesh::Quality::name().

Referenced by libMesh::ReferenceCounter::print_info().

{
#if defined(LIBMESH_ENABLE_REFERENCE_COUNTING) && defined(DEBUG)

  std::ostringstream oss;

  oss << '\n'
      << " ---------------------------------------------------------------------------- \n"
      << "| Reference count information                                                |\n"
      << " ---------------------------------------------------------------------------- \n";

  for (Counts::iterator it = _counts.begin();
       it != _counts.end(); ++it)
    {
      const std::string name(it->first);
      const unsigned int creations    = it->second.first;
      const unsigned int destructions = it->second.second;

      oss << "| " << name << " reference count information:\n"
          << "|  Creations:    " << creations    << '\n'
          << "|  Destructions: " << destructions << '\n';
    }

  oss << " ---------------------------------------------------------------------------- \n";

  return oss.str();

#else

  return "";

#endif
}

void libMesh::ReferenceCounter::increment_constructor_count

(

const std::string &

name

)

[inline, protected, inherited]

Increments the construction counter. Should be called in the constructor of any derived class that will be reference counted.

Definition at line 163 of file reference_counter.h.

References libMesh::ReferenceCounter::_counts, and libMesh::Threads::spin_mtx.

Referenced by libMesh::ReferenceCountedObject< RBParametrized >::ReferenceCountedObject().

{
  Threads::spin_mutex::scoped_lock lock(Threads::spin_mtx);
  std::pair<unsigned int, unsigned int>& p = _counts[name];

  p.first++;
}

void libMesh::ReferenceCounter::increment_destructor_count

(

const std::string &

name

)

[inline, protected, inherited]

Increments the destruction counter. Should be called in the destructor of any derived class that will be reference counted.

Definition at line 176 of file reference_counter.h.

References libMesh::ReferenceCounter::_counts, and libMesh::Threads::spin_mtx.

Referenced by libMesh::ReferenceCountedObject< RBParametrized >::~ReferenceCountedObject().

{
  Threads::spin_mutex::scoped_lock lock(Threads::spin_mtx);
  std::pair<unsigned int, unsigned int>& p = _counts[name];

  p.second++;
}

void libMesh::UnsteadySolver::init

(

)

[virtual, inherited]

The initialization function. This method is used to initialize internal data structures before a simulation begins.

Reimplemented from libMesh::TimeSolver.

Reimplemented in libMesh::AdaptiveTimeSolver.

Definition at line 46 of file unsteady_solver.C.

References libMesh::TimeSolver::_system, and libMesh::System::add_vector().

{
  TimeSolver::init();

  _system.add_vector("_old_nonlinear_solution");
}

void libMesh::UnsteadySolver::init_data

(

)

[virtual, inherited]

The data initialization function. This method is used to initialize internal data structures after the underlying System has been initialized

Reimplemented from libMesh::TimeSolver.

Definition at line 55 of file unsteady_solver.C.

References libMesh::TimeSolver::_system, libMesh::System::get_dof_map(), libMesh::DofMap::get_send_list(), libMeshEnums::GHOSTED, libMesh::System::n_dofs(), libMesh::System::n_local_dofs(), libMesh::UnsteadySolver::old_local_nonlinear_solution, and libMeshEnums::SERIAL.

{
#ifdef LIBMESH_ENABLE_GHOSTED
  old_local_nonlinear_solution->init (_system.n_dofs(), _system.n_local_dofs(),
                                      _system.get_dof_map().get_send_list(), false,
                                      GHOSTED);
#else
  old_local_nonlinear_solution->init (_system.n_dofs(), false, SERIAL);
#endif
}

bool libMesh::TimeSolver::is_adjoint

(

)

const [inline, inherited]

Accessor for querying whether we need to do a primal or adjoint solve

Definition at line 217 of file time_solver.h.

References libMesh::TimeSolver::_is_adjoint.

Referenced by libMesh::FEMSystem::build_context().

  { return _is_adjoint; }

virtual bool libMesh::UnsteadySolver::is_steady

(

)

const [inline, virtual, inherited]

This is not a steady-state solver.

Implements libMesh::TimeSolver.

Definition at line 149 of file unsteady_solver.h.

{ return false; }

virtual AutoPtr<LinearSolver<Number> >& libMesh::TimeSolver::linear_solver

(

)

[inline, virtual, inherited]

An implicit linear solver to use for adjoint and sensitivity problems.

Definition at line 172 of file time_solver.h.

References libMesh::TimeSolver::_linear_solver.

{ return _linear_solver; }

static unsigned int libMesh::ReferenceCounter::n_objects

(

)

[inline, static, inherited]

Prints the number of outstanding (created, but not yet destroyed) objects.

Definition at line 79 of file reference_counter.h.

References libMesh::ReferenceCounter::_n_objects.

  { return _n_objects; }

Number libMesh::UnsteadySolver::old_nonlinear_solution

(

const dof_id_type

global_dof_number

)

const [inherited]

Returns:

the old nonlinear solution for the specified global DOF.

Definition at line 207 of file unsteady_solver.C.

References libMesh::TimeSolver::_system, libMesh::System::get_dof_map(), libMesh::DofMap::n_dofs(), and libMesh::UnsteadySolver::old_local_nonlinear_solution.

Referenced by element_residual(), libMesh::Euler2Solver::element_residual(), side_residual(), and libMesh::Euler2Solver::side_residual().

{
  libmesh_assert_less (global_dof_number, _system.get_dof_map().n_dofs());
  libmesh_assert_less (global_dof_number, old_local_nonlinear_solution->size());

  return (*old_local_nonlinear_solution)(global_dof_number);
}

void libMesh::ReferenceCounter::print_info

(

std::ostream &

out = libMesh::out

)

[static, inherited]

Prints the reference information, by default to libMesh::out.

Definition at line 88 of file reference_counter.C.

References libMesh::ReferenceCounter::_enable_print_counter, and libMesh::ReferenceCounter::get_info().

{
  if( _enable_print_counter ) out_stream << ReferenceCounter::get_info();
}

void libMesh::UnsteadySolver::reinit

(

)

[virtual, inherited]

The reinitialization function. This method is used to resize internal data vectors after a mesh change.

Reimplemented from libMesh::TimeSolver.

Reimplemented in libMesh::AdaptiveTimeSolver.

Definition at line 68 of file unsteady_solver.C.

References libMesh::TimeSolver::_system, libMesh::System::get_dof_map(), libMesh::DofMap::get_send_list(), libMeshEnums::GHOSTED, libMesh::System::n_dofs(), libMesh::System::n_local_dofs(), libMesh::UnsteadySolver::old_local_nonlinear_solution, and libMeshEnums::SERIAL.

{
  TimeSolver::reinit();

#ifdef LIBMESH_ENABLE_GHOSTED
  old_local_nonlinear_solution->init (_system.n_dofs(), _system.n_local_dofs(),
                                      _system.get_dof_map().get_send_list(), false,
                                      GHOSTED);
#else
  old_local_nonlinear_solution->init (_system.n_dofs(), false, SERIAL);
#endif

}

void libMesh::UnsteadySolver::retrieve_timestep

(

)

[virtual, inherited]

This method retrieves all the stored solutions at the current system.time

Reimplemented from libMesh::TimeSolver.

Definition at line 195 of file unsteady_solver.C.

References libMesh::TimeSolver::_system, libMesh::System::get_dof_map(), libMesh::DofMap::get_send_list(), libMesh::System::get_vector(), libMesh::NumericVector< T >::localize(), libMesh::UnsteadySolver::old_local_nonlinear_solution, and libMesh::TimeSolver::solution_history.

  {
    // Retrieve all the stored vectors at the current time
    solution_history->retrieve();

    // Dont forget to localize the old_nonlinear_solution !
    _system.get_vector("_old_nonlinear_solution").localize
    (*old_local_nonlinear_solution,
     _system.get_dof_map().get_send_list());
  }

void libMesh::TimeSolver::set_is_adjoint

(

bool

_is_adjoint_value

)

[inline, inherited]

Accessor for setting whether we need to do a primal or adjoint solve

Definition at line 224 of file time_solver.h.

References libMesh::TimeSolver::_is_adjoint.

Referenced by libMesh::DifferentiableSystem::adjoint_solve(), libMesh::FEMSystem::postprocess(), and libMesh::DifferentiableSystem::solve().

  { _is_adjoint = _is_adjoint_value; }

void libMesh::TimeSolver::set_solution_history

(

const SolutionHistory &

_solution_history

)

[inherited]

A setter function users will employ if they need to do something other than save no solution history

Definition at line 91 of file time_solver.C.

References libMesh::SolutionHistory::clone(), and libMesh::TimeSolver::solution_history.

 {
   solution_history = _solution_history.clone();
 }

bool libMesh::EulerSolver::side_residual	(	bool	request_jacobian,
		DiffContext &	context
	)			[virtual]

This method uses the DifferentiableSystem's side_time_derivative() and side_constraint() to build a full residual on an element's side. What combination it uses will depend on theta.

Implements libMesh::TimeSolver.

Definition at line 156 of file euler_solver.C.

References libMesh::TimeSolver::_system, libMesh::DenseVector< T >::add(), libMesh::DifferentiableSystem::deltat, libMesh::DiffContext::dof_indices, libMesh::DiffContext::elem_fixed_solution, libMesh::DiffContext::elem_jacobian, libMesh::DiffContext::elem_residual, libMesh::DiffContext::elem_side_reinit(), libMesh::DiffContext::elem_solution, libMesh::DiffContext::elem_solution_derivative, libMesh::DiffContext::fixed_solution_derivative, libMesh::UnsteadySolver::old_nonlinear_solution(), libMesh::DifferentiablePhysics::side_constraint(), libMesh::DifferentiablePhysics::side_mass_residual(), libMesh::DifferentiablePhysics::side_time_derivative(), libMesh::DenseVector< T >::size(), libMesh::DenseMatrix< T >::swap(), libMesh::DenseVector< T >::swap(), theta, libMesh::System::use_fixed_solution, libMesh::DenseVector< T >::zero(), and libMesh::DenseMatrix< T >::zero().

{
  unsigned int n_dofs = context.elem_solution.size();

  // Local nonlinear solution at old timestep
  DenseVector<Number> old_elem_solution(n_dofs);
  for (unsigned int i=0; i != n_dofs; ++i)
    old_elem_solution(i) =
      old_nonlinear_solution(context.dof_indices[i]);

  // Local nonlinear solution at time t_theta
  DenseVector<Number> theta_solution(context.elem_solution);
  theta_solution *= theta;
  theta_solution.add(1. - theta, old_elem_solution);

  // Technically the elem_solution_derivative is either theta
  // or 1.0 in this implementation, but we scale the former part
  // ourselves
  context.elem_solution_derivative = 1.0;

// Technically the fixed_solution_derivative is always theta,
// but we're scaling a whole jacobian by theta after these first
// evaluations
  context.fixed_solution_derivative = 1.0;

  // If a fixed solution is requested, we'll use theta_solution
  if (_system.use_fixed_solution)
    context.elem_fixed_solution = theta_solution;

  // Move theta_->elem_, elem_->theta_
  context.elem_solution.swap(theta_solution);

  // Move the mesh into place first if necessary
  context.elem_side_reinit(theta);

  // We're going to compute just the change in elem_residual
  // (and possibly elem_jacobian), then add back the old values
  DenseVector<Number> old_elem_residual(context.elem_residual);
  DenseMatrix<Number> old_elem_jacobian;
  if (request_jacobian)
    {
      old_elem_jacobian = context.elem_jacobian;
      context.elem_jacobian.zero();
    }
  context.elem_residual.zero();

  // Get the time derivative at t_theta
  bool jacobian_computed =
    _system.side_time_derivative(request_jacobian, context);

  // Scale the time-dependent residual and jacobian correctly
  context.elem_residual *= _system.deltat;
  if (jacobian_computed)
    context.elem_jacobian *= (theta * _system.deltat);

  // The fixed_solution_derivative is always theta,
  // and now we're done scaling jacobians
  context.fixed_solution_derivative = theta;

  // We evaluate side_mass_residual with the change in solution
  // to get the mass matrix, reusing old_elem_solution to hold that
  // delta_solution.  We're solving dt*F(u) - du = 0, so our
  // delta_solution is old_solution - new_solution.
  // We're still keeping elem_solution in theta_solution for now
  old_elem_solution -= theta_solution;

  // Move old_->elem_, theta_->old_
  context.elem_solution.swap(old_elem_solution);

  // We do a trick here to avoid using a non-1
  // elem_solution_derivative:
  context.elem_jacobian *= -1.0;
  jacobian_computed = _system.side_mass_residual(jacobian_computed, context) &&
    jacobian_computed;
  context.elem_jacobian *= -1.0;

  // Move elem_->elem_, old_->theta_
  context.elem_solution.swap(theta_solution);

  // Restore the elem position if necessary
  context.elem_side_reinit(1.);

  // Add the constraint term
  jacobian_computed = _system.side_constraint(jacobian_computed, context) &&
    jacobian_computed;

  // Add back the old residual and jacobian
  context.elem_residual += old_elem_residual;
  if (request_jacobian)
    {
      if (jacobian_computed)
        context.elem_jacobian += old_elem_jacobian;
      else
        context.elem_jacobian.swap(old_elem_jacobian);
    }

  return jacobian_computed;
}

void libMesh::UnsteadySolver::solve

(

)

[virtual, inherited]

This method solves for the solution at the next timestep. Usually we will only need to solve one (non)linear system per timestep, but more complex subclasses may override this.

Reimplemented from libMesh::TimeSolver.

Reimplemented in libMesh::AdaptiveTimeSolver, and libMesh::TwostepTimeSolver.

Definition at line 84 of file unsteady_solver.C.

References libMesh::TimeSolver::_diff_solver, libMesh::TimeSolver::_system, libMesh::UnsteadySolver::advance_timestep(), libMesh::DifferentiableSystem::deltat, libMesh::DiffSolver::DIVERGED_BACKTRACKING_FAILURE, libMesh::DiffSolver::DIVERGED_MAX_NONLINEAR_ITERATIONS, libMesh::UnsteadySolver::first_solve, libMesh::out, libMesh::TimeSolver::quiet, and libMesh::TimeSolver::reduce_deltat_on_diffsolver_failure.

{
  if (first_solve)
    {
      advance_timestep();
      first_solve = false;
    }

  unsigned int solve_result = _diff_solver->solve();

  // If we requested the UnsteadySolver to attempt reducing dt after a
  // failed DiffSolver solve, check the results of the solve now.
  if (reduce_deltat_on_diffsolver_failure)
    {
      bool backtracking_failed =
        solve_result & DiffSolver::DIVERGED_BACKTRACKING_FAILURE;

      bool max_iterations =
        solve_result & DiffSolver::DIVERGED_MAX_NONLINEAR_ITERATIONS;

      if (backtracking_failed || max_iterations)
        {
          // Cut timestep in half
          for (unsigned int nr=0; nr<reduce_deltat_on_diffsolver_failure; ++nr)
            {
              _system.deltat *= 0.5;
              libMesh::out << "Newton backtracking failed.  Trying with smaller timestep, dt="
                            << _system.deltat << std::endl;

              solve_result = _diff_solver->solve();

              // Check solve results with reduced timestep
              bool backtracking_still_failed =
                solve_result & DiffSolver::DIVERGED_BACKTRACKING_FAILURE;

              bool backtracking_max_iterations =
                solve_result & DiffSolver::DIVERGED_MAX_NONLINEAR_ITERATIONS;

              if (!backtracking_still_failed && !backtracking_max_iterations)
                {
                  if (!quiet)
                    libMesh::out << "Reduced dt solve succeeded." << std::endl;
                  return;
                }
            }

          // If we made it here, we still couldn't converge the solve after
          // reducing deltat
          libMesh::out << "DiffSolver::solve() did not succeed after "
                        << reduce_deltat_on_diffsolver_failure
                        << " attempts." << std::endl;
          libmesh_convergence_failure();

        } // end if (backtracking_failed || max_iterations)
    } // end if (reduce_deltat_on_diffsolver_failure)
}

sys_type& libMesh::TimeSolver::system

(

)

[inline, inherited]

Returns:

a writeable reference to the system we are solving.

Definition at line 162 of file time_solver.h.

References libMesh::TimeSolver::_system.

{ return _system; }

const sys_type& libMesh::TimeSolver::system

(

)

const [inline, inherited]

Returns:

a constant reference to the system we are solving.

Definition at line 157 of file time_solver.h.

References libMesh::TimeSolver::_system.

Referenced by libMesh::TimeSolver::reinit(), and libMesh::TimeSolver::solve().

{ return _system; }

---

Member Data Documentation

ReferenceCounter::Counts libMesh::ReferenceCounter::_counts [static, protected, inherited]

Actually holds the data.

Definition at line 118 of file reference_counter.h.

Referenced by libMesh::ReferenceCounter::get_info(), libMesh::ReferenceCounter::increment_constructor_count(), and libMesh::ReferenceCounter::increment_destructor_count().

AutoPtr<DiffSolver> libMesh::TimeSolver::_diff_solver [protected, inherited]

An implicit linear or nonlinear solver to use at each timestep.

Definition at line 232 of file time_solver.h.

Referenced by libMesh::TimeSolver::diff_solver(), libMesh::TimeSolver::init(), libMesh::TimeSolver::reinit(), libMesh::UnsteadySolver::solve(), and libMesh::TimeSolver::solve().

bool libMesh::ReferenceCounter::_enable_print_counter = true [static, protected, inherited]

Flag to control whether reference count information is printed when print_info is called.

Definition at line 137 of file reference_counter.h.

Referenced by libMesh::ReferenceCounter::disable_print_counter_info(), libMesh::ReferenceCounter::enable_print_counter_info(), and libMesh::ReferenceCounter::print_info().

AutoPtr<LinearSolver<Number> > libMesh::TimeSolver::_linear_solver [protected, inherited]

An implicit linear solver to use for adjoint problems.

Definition at line 237 of file time_solver.h.

Referenced by libMesh::TimeSolver::init(), libMesh::TimeSolver::linear_solver(), and libMesh::TimeSolver::reinit().

Threads::spin_mutex libMesh::ReferenceCounter::_mutex [static, protected, inherited]

Mutual exclusion object to enable thread-safe reference counting.

Definition at line 131 of file reference_counter.h.

Threads::atomic< unsigned int > libMesh::ReferenceCounter::_n_objects [static, protected, inherited]

The number of objects. Print the reference count information when the number returns to 0.

Definition at line 126 of file reference_counter.h.

Referenced by libMesh::ReferenceCounter::n_objects(), libMesh::ReferenceCounter::ReferenceCounter(), and libMesh::ReferenceCounter::~ReferenceCounter().

sys_type& libMesh::TimeSolver::_system [protected, inherited]

A reference to the system we are solving.

Definition at line 242 of file time_solver.h.

Referenced by libMesh::UnsteadySolver::adjoint_advance_timestep(), libMesh::UnsteadySolver::advance_timestep(), libMesh::AdaptiveTimeSolver::advance_timestep(), libMesh::UnsteadySolver::du(), libMesh::SteadySolver::element_residual(), element_residual(), libMesh::Euler2Solver::element_residual(), libMesh::EigenTimeSolver::element_residual(), libMesh::UnsteadySolver::init(), libMesh::TimeSolver::init(), libMesh::EigenTimeSolver::init(), libMesh::UnsteadySolver::init_data(), libMesh::UnsteadySolver::old_nonlinear_solution(), libMesh::UnsteadySolver::reinit(), libMesh::UnsteadySolver::retrieve_timestep(), libMesh::SteadySolver::side_residual(), side_residual(), libMesh::Euler2Solver::side_residual(), libMesh::EigenTimeSolver::side_residual(), libMesh::UnsteadySolver::solve(), libMesh::TwostepTimeSolver::solve(), libMesh::EigenTimeSolver::solve(), and libMesh::TimeSolver::system().

bool libMesh::UnsteadySolver::first_adjoint_step [protected, inherited]

A bool that will be true the first time adjoint_advance_timestep() is called, (when the primal solution is to be used to set adjoint boundary conditions) and false thereafter

Definition at line 163 of file unsteady_solver.h.

Referenced by libMesh::UnsteadySolver::adjoint_advance_timestep().

bool libMesh::UnsteadySolver::first_solve [protected, inherited]

A bool that will be true the first time solve() is called, and false thereafter

Reimplemented from libMesh::TimeSolver.

Definition at line 157 of file unsteady_solver.h.

Referenced by libMesh::UnsteadySolver::advance_timestep(), libMesh::AdaptiveTimeSolver::advance_timestep(), libMesh::UnsteadySolver::solve(), and libMesh::TwostepTimeSolver::solve().

AutoPtr<NumericVector<Number> > libMesh::UnsteadySolver::old_local_nonlinear_solution [inherited]

Serial vector of _system.get_vector("_old_nonlinear_solution")

Reimplemented from libMesh::TimeSolver.

Definition at line 133 of file unsteady_solver.h.

Referenced by libMesh::AdaptiveTimeSolver::AdaptiveTimeSolver(), libMesh::UnsteadySolver::adjoint_advance_timestep(), libMesh::UnsteadySolver::advance_timestep(), libMesh::AdaptiveTimeSolver::init(), libMesh::UnsteadySolver::init_data(), libMesh::UnsteadySolver::old_nonlinear_solution(), libMesh::UnsteadySolver::reinit(), libMesh::UnsteadySolver::retrieve_timestep(), and libMesh::AdaptiveTimeSolver::~AdaptiveTimeSolver().

bool libMesh::TimeSolver::quiet [inherited]

Print extra debugging information if quiet == false.

Definition at line 177 of file time_solver.h.

Referenced by libMesh::UnsteadySolver::solve(), libMesh::TwostepTimeSolver::solve(), and libMesh::EigenTimeSolver::solve().

unsigned int libMesh::TimeSolver::reduce_deltat_on_diffsolver_failure [inherited]

This value (which defaults to zero) is the number of times the TimeSolver is allowed to halve deltat and let the DiffSolver repeat the latest failed solve with a reduced timestep. Note that this has no effect for SteadySolvers. Note that you must set at least one of the DiffSolver flags "continue_after_max_iterations" or "continue_after_backtrack_failure" to allow the TimeSolver to retry the solve.

Definition at line 205 of file time_solver.h.

Referenced by libMesh::UnsteadySolver::solve(), and libMesh::TwostepTimeSolver::solve().

AutoPtr<SolutionHistory> libMesh::TimeSolver::solution_history [protected, inherited]

An AutoPtr to a SolutionHistory object. Default is NoSolutionHistory, which the user can override by declaring a different kind of SolutionHistory in the application

Definition at line 260 of file time_solver.h.

Referenced by libMesh::UnsteadySolver::adjoint_advance_timestep(), libMesh::UnsteadySolver::advance_timestep(), libMesh::UnsteadySolver::retrieve_timestep(), and libMesh::TimeSolver::set_solution_history().

Real libMesh::EulerSolver::theta

The value for the theta method to employ: 1.0 corresponds to backwards Euler, 0.0 corresponds to forwards Euler, 0.5 corresponds to Crank-Nicolson.

Definition at line 93 of file euler_solver.h.

Referenced by element_residual(), error_order(), and side_residual().

---

The documentation for this class was generated from the following files:

• euler_solver.h
• euler_solver.C