PetscContactLineSearch Class Reference

Petsc implementation of the contact line search (based on the Petsc LineSearchShell) More...

#include <PetscContactLineSearch.h>

Inheritance diagram for PetscContactLineSearch:

Public Member Functions
	PetscContactLineSearch (const InputParameters &parameters)
virtual void	lineSearch () override
void	printContactInfo (const std::set< dof_id_type > &contact_set)
	Method for printing the contact information. More...
void	insertSet (const std::set< dof_id_type > &mech_set)
	Unionize sets from different constraints. More...
virtual void	reset ()
	Reset the line search data. More...

Protected Attributes
PetscNonlinearSolver< Real > *	_solver
std::set< dof_id_type >	_current_contact_state
	The current contact set. More...
std::set< dof_id_type >	_old_contact_state
	The old contact set. More...
Real	_user_ksp_rtol
	the linear tolerance set by the user in the input file More...
bool	_user_ksp_rtol_set
	Whether the user linear tolerance has been set yet in this object. More...
Real	_contact_lambda
	The multiplier of the newton step. More...
unsigned	_allowed_lambda_cuts
	How many times the linsearch is allowed to cut lambda. More...
Real	_contact_ltol
	What the linear tolerance should be while the contact state is changing. More...
bool	_affect_ltol
	Whether to modify the linear tolerance. More...

Detailed Description

Petsc implementation of the contact line search (based on the Petsc LineSearchShell)

Definition at line 36 of file PetscContactLineSearch.h.

Constructor & Destructor Documentation

PetscContactLineSearch()

PetscContactLineSearch::PetscContactLineSearch

(

const InputParameters &

parameters

)

Definition at line 29 of file PetscContactLineSearch.C.

  : ContactLineSearchBase(parameters)
{
  _solver = dynamic_cast<PetscNonlinearSolver<Real> *>(
      _fe_problem.getNonlinearSystem().nonlinearSolver());
  if (!_solver)
    mooseError(
        "This line search operates only with Petsc, so Petsc must be your nonlinear solver.");
}

Member Function Documentation

insertSet()

void ContactLineSearchBase::insertSet ( const std::set< dof_id_type > &  mech_set )

inherited

Unionize sets from different constraints.

Definition at line 54 of file ContactLineSearchBase.C.

{
  if (_current_contact_state.empty())
    _current_contact_state = mech_set;
  else
    for (auto & node : mech_set)
      _current_contact_state.insert(node);
}

Referenced by MechanicalContactConstraint::residualEnd().

lineSearch()

void PetscContactLineSearch::lineSearch ( )

overridevirtual

Definition at line 40 of file PetscContactLineSearch.C.

{
  PetscBool changed_y = PETSC_FALSE, changed_w = PETSC_FALSE;
  PetscErrorCode ierr;
  Vec X, F, Y, W, G, W1;
  SNESLineSearch line_search;
  PetscReal fnorm, xnorm, ynorm, gnorm;
  PetscBool domainerror;
  PetscReal ksp_rtol, ksp_abstol, ksp_dtol;
  PetscInt ksp_maxits;
  KSP ksp;
  SNES snes = _solver->snes();
 
  ierr = SNESGetLineSearch(snes, &line_search);
  LIBMESH_CHKERR(ierr);
  ierr = SNESLineSearchGetVecs(line_search, &X, &F, &Y, &W, &G);
  LIBMESH_CHKERR(ierr);
  ierr = SNESLineSearchGetNorms(line_search, &xnorm, &fnorm, &ynorm);
  LIBMESH_CHKERR(ierr);
  ierr = SNESLineSearchGetSNES(line_search, &snes);
  LIBMESH_CHKERR(ierr);
  ierr = SNESLineSearchSetReason(line_search, SNES_LINESEARCH_SUCCEEDED);
  LIBMESH_CHKERR(ierr);
  ierr = SNESGetKSP(snes, &ksp);
  LIBMESH_CHKERR(ierr);
  ierr = KSPGetTolerances(ksp, &ksp_rtol, &ksp_abstol, &ksp_dtol, &ksp_maxits);
  LIBMESH_CHKERR(ierr);
  ierr = VecDuplicate(W, &W1);
  LIBMESH_CHKERR(ierr);
 
  if (!_user_ksp_rtol_set)
  {
    _user_ksp_rtol = ksp_rtol;
    _user_ksp_rtol_set = true;
  }
 
  ++_nl_its;
 
  /* precheck */
  ierr = SNESLineSearchPreCheck(line_search, X, Y, &changed_y);
  LIBMESH_CHKERR(ierr);
 
  /* temporary update */
  _contact_lambda = 1.;
  ierr = VecWAXPY(W, -_contact_lambda, Y, X);
  LIBMESH_CHKERR(ierr);
 
  /* compute residual to determine whether contact state has changed since the last non-linear
   * residual evaluation */
  _current_contact_state.clear();
  ierr = SNESComputeFunction(snes, W, F);
  LIBMESH_CHKERR(ierr);
  ierr = SNESGetFunctionDomainError(snes, &domainerror);
  LIBMESH_CHKERR(ierr);
  if (domainerror)
  {
    ierr = SNESLineSearchSetReason(line_search, SNES_LINESEARCH_FAILED_DOMAIN);
    LIBMESH_CHKERR(ierr);
  }
  ierr = VecNorm(F, NORM_2, &fnorm);
  LIBMESH_CHKERR(ierr);
  std::set<dof_id_type> contact_state_stored = _current_contact_state;
  _current_contact_state.clear();
  printContactInfo(contact_state_stored);
 
  if (_affect_ltol)
  {
    if (contact_state_stored != _old_contact_state)
    {
      KSPSetTolerances(ksp, _contact_ltol, ksp_abstol, ksp_dtol, ksp_maxits);
      _console << "Contact set changed since previous non-linear iteration!\n";
    }
    else
      KSPSetTolerances(ksp, _user_ksp_rtol, ksp_abstol, ksp_dtol, ksp_maxits);
  }
 
  size_t ls_its = 0;
  while (ls_its < _allowed_lambda_cuts)
  {
    _contact_lambda *= 0.5;
    /* update */
    ierr = VecWAXPY(W1, -_contact_lambda, Y, X);
    LIBMESH_CHKERR(ierr);
 
    ierr = SNESComputeFunction(snes, W1, G);
    LIBMESH_CHKERR(ierr);
    ierr = SNESGetFunctionDomainError(snes, &domainerror);
    LIBMESH_CHKERR(ierr);
    if (domainerror)
    {
      ierr = SNESLineSearchSetReason(line_search, SNES_LINESEARCH_FAILED_DOMAIN);
      LIBMESH_CHKERR(ierr);
    }
    ierr = VecNorm(G, NORM_2, &gnorm);
    LIBMESH_CHKERR(ierr);
    if (gnorm < fnorm)
    {
      VecCopy(G, F);
      LIBMESH_CHKERR(ierr);
      VecCopy(W1, W);
      LIBMESH_CHKERR(ierr);
      fnorm = gnorm;
      contact_state_stored.swap(_current_contact_state);
      _current_contact_state.clear();
      printContactInfo(contact_state_stored);
      ++ls_its;
    }
    else
      break;
  }
 
  ierr = VecScale(Y, _contact_lambda);
  LIBMESH_CHKERR(ierr);
  /* postcheck */
  ierr = SNESLineSearchPostCheck(line_search, X, Y, W, &changed_y, &changed_w);
  LIBMESH_CHKERR(ierr);
 
  if (changed_y)
  {
    ierr = VecWAXPY(W, -1., Y, X);
    LIBMESH_CHKERR(ierr);
  }
 
  if (changed_w || changed_y)
  {
    ierr = SNESComputeFunction(snes, W, F);
    LIBMESH_CHKERR(ierr);
    ierr = SNESGetFunctionDomainError(snes, &domainerror);
    LIBMESH_CHKERR(ierr);
    if (domainerror)
    {
      ierr = SNESLineSearchSetReason(line_search, SNES_LINESEARCH_FAILED_DOMAIN);
      LIBMESH_CHKERR(ierr);
    }
    contact_state_stored.swap(_current_contact_state);
    _current_contact_state.clear();
    printContactInfo(contact_state_stored);
  }
 
  /* copy the solution over */
  ierr = VecCopy(W, X);
  LIBMESH_CHKERR(ierr);
 
  ierr = SNESLineSearchComputeNorms(line_search);
  LIBMESH_CHKERR(ierr);
 
  ierr = VecDestroy(&W1);
  LIBMESH_CHKERR(ierr);
 
  _old_contact_state = std::move(contact_state_stored);
}

printContactInfo()

void ContactLineSearchBase::printContactInfo ( const std::set< dof_id_type > &  contact_set )

inherited

Method for printing the contact information.

Definition at line 45 of file ContactLineSearchBase.C.

{
  if (!contact_set.empty())
    _console << contact_set.size() << " nodes in contact\n";
  else
    _console << "No nodes in contact\n";
}

Referenced by lineSearch().

reset()

void ContactLineSearchBase::reset ( )

virtualinherited

Reset the line search data.

Definition at line 64 of file ContactLineSearchBase.C.

{
  _current_contact_state.clear();
  zeroIts();
}

Referenced by MechanicalContactConstraint::timestepSetup().

Member Data Documentation

_affect_ltol

bool ContactLineSearchBase::_affect_ltol

protectedinherited

Whether to modify the linear tolerance.

Definition at line 79 of file ContactLineSearchBase.h.

Referenced by lineSearch().

_allowed_lambda_cuts

unsigned ContactLineSearchBase::_allowed_lambda_cuts

protectedinherited

How many times the linsearch is allowed to cut lambda.

Definition at line 73 of file ContactLineSearchBase.h.

Referenced by lineSearch().

_contact_lambda

Real ContactLineSearchBase::_contact_lambda

protectedinherited

The multiplier of the newton step.

Definition at line 70 of file ContactLineSearchBase.h.

Referenced by lineSearch().

_contact_ltol

Real ContactLineSearchBase::_contact_ltol

protectedinherited

What the linear tolerance should be while the contact state is changing.

Definition at line 76 of file ContactLineSearchBase.h.

Referenced by lineSearch().

_current_contact_state

std::set<dof_id_type> ContactLineSearchBase::_current_contact_state

protectedinherited

The current contact set.

Definition at line 60 of file ContactLineSearchBase.h.

Referenced by ContactLineSearchBase::insertSet(), lineSearch(), and ContactLineSearchBase::reset().

_old_contact_state

std::set<dof_id_type> ContactLineSearchBase::_old_contact_state

protectedinherited

The old contact set.

Definition at line 62 of file ContactLineSearchBase.h.

Referenced by lineSearch().

_solver

PetscNonlinearSolver<Real>* PetscContactLineSearch::_solver

protected

Definition at line 44 of file PetscContactLineSearch.h.

Referenced by lineSearch(), and PetscContactLineSearch().

_user_ksp_rtol

Real ContactLineSearchBase::_user_ksp_rtol

protectedinherited

the linear tolerance set by the user in the input file

Definition at line 65 of file ContactLineSearchBase.h.

Referenced by lineSearch().

_user_ksp_rtol_set

bool ContactLineSearchBase::_user_ksp_rtol_set

protectedinherited

Whether the user linear tolerance has been set yet in this object.

Definition at line 67 of file ContactLineSearchBase.h.

Referenced by lineSearch().

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

• contact/include/linesearches/PetscContactLineSearch.h
• contact/src/linesearches/PetscContactLineSearch.C