www.mooseframework.org
ExplicitTVDRK2.C
Go to the documentation of this file.
1 //* This file is part of the MOOSE framework
2 //* https://www.mooseframework.org
3 //*
4 //* All rights reserved, see COPYRIGHT for full restrictions
5 //* https://github.com/idaholab/moose/blob/master/COPYRIGHT
6 //*
7 //* Licensed under LGPL 2.1, please see LICENSE for details
8 //* https://www.gnu.org/licenses/lgpl-2.1.html
9 
10 #include "ExplicitTVDRK2.h"
11 #include "NonlinearSystemBase.h"
12 #include "FEProblem.h"
13 #include "PetscSupport.h"
14 
16 
19 {
21  params.addClassDescription("Explicit TVD (total-variation-diminishing) second-order Runge-Kutta "
22  "time integration method.");
23  return params;
24 }
25 
27  : TimeIntegrator(parameters),
28  _stage(1),
29  _residual_old(_nl.addVector("residual_old", false, GHOSTED)),
30  _solution_older(_sys.solutionState(2))
31 {
32  mooseInfo("ExplicitTVDRK2 and other multistage TimeIntegrators are known not to work with "
33  "Materials/AuxKernels that accumulate 'state' and should be used with caution.");
34 }
35 
36 void
38 {
39  if (_dt == _dt_old)
41  else
43 }
44 
45 void
47 {
48  // Since advanceState() is called in between stages 2 and 3, this
49  // changes the meaning of "_solution_old". In the second stage,
50  // "_solution_older" is actually the original _solution_old.
51  if (!_sys.solutionUDot())
52  mooseError("ExplicitTVDRK2: Time derivative of solution (`u_dot`) is not stored. Please set "
53  "uDotRequested() to true in FEProblemBase befor requesting `u_dot`.");
54 
56  u_dot = *_solution;
58 
59  _du_dot_du = 1. / _dt;
60  u_dot.close();
61 }
62 
63 void
65  const dof_id_type & dof,
66  DualReal & /*ad_u_dotdot*/) const
67 {
69 }
70 
71 void
73 {
74  Real time_new = _fe_problem.time();
75  Real time_old = _fe_problem.timeOld();
76  Real time_stage2 = time_old + _dt;
77 
78  // Reset numbers of iterations
81 
82  // There is no work to do for the first stage (Y_1 = y_n). The
83  // first solve therefore happens in the second stage. Note that the
84  // non-time Kernels (which should be marked implicit=false) are
85  // evaluated at the old solution during this stage.
87  _console << "1st solve" << std::endl;
88  _stage = 2;
89  _fe_problem.timeOld() = time_old;
90  _fe_problem.time() = time_stage2;
91  _nl.system().solve();
94 
95  // Abort time step immediately on stage failure - see TimeIntegrator doc page
97  return;
98 
99  // Advance solutions old->older, current->old. Also moves Material
100  // properties and other associated state forward in time.
102 
103  // The "update" stage (which we call stage 3) requires an additional
104  // solve with the mass matrix.
106  _console << "2nd solve" << std::endl;
107  _stage = 3;
108  _fe_problem.timeOld() = time_stage2;
109  _fe_problem.time() = time_new;
110  _nl.system().solve();
113 
114  // Reset time at beginning of step to its original value
115  _fe_problem.timeOld() = time_old;
116 }
117 
118 void
120 {
121  if (_stage == 1)
122  {
123  // If postResidual() is called before solve(), _stage==1 and we don't
124  // need to do anything.
125  }
126  else if (_stage == 2)
127  {
128  // In the standard RK notation, the stage 2 residual is given by:
129  //
130  // R := M*(Y_2 - y_n)/dt - f(t_n, Y_1) = 0
131  //
132  // where:
133  // .) M is the mass matrix.
134  // .) f(t_n, Y_1) is the residual we are currently computing,
135  // since this method is intended to be used with "implicit=false"
136  // kernels.
137  // .) M*(Y_2 - y_n)/dt corresponds to the residual of the time kernels.
138  // .) The minus signs are "baked in" to the non-time residuals, so
139  // they do not appear here.
140  // .) The current non-time residual is saved for the next stage.
143 
144  residual.add(1.0, _Re_time);
145  residual.add(1.0, _residual_old);
146  residual.close();
147  }
148  else if (_stage == 3)
149  {
150  // In the standard RK notation, the update step residual is given by:
151  //
152  // R := M*(2*y_{n+1} - Y_2 - y_n)/(2*dt) - (1/2)*f(t_n+dt/2, Y_2) = 0
153  //
154  // where:
155  // .) M is the mass matrix.
156  // .) f(t_n+dt/2, Y_2) is the residual from stage 2.
157  // .) The minus sign is already baked in to the non-time
158  // residuals, so it does not appear here.
159  // .) Although this is an update step, we have to do a "solve"
160  // using the mass matrix.
161  residual.add(1.0, _Re_time);
162  residual.add(0.5, _Re_non_time);
163  residual.close();
164  }
165  else
166  mooseError(
167  "ExplicitTVDRK2::postResidual(): _stage = ", _stage, ", only _stage = 1-3 is allowed.");
168 }
NonlinearSystemBase & _nl
virtual void computeTimeDerivatives() override
Computes the time derivative and the Jacobian of the time derivative.
virtual void initPetscOutputAndSomeSolverSettings()
Reinitialize PETSc output for proper linear/nonlinear iteration display.
void computeTimeDerivativeHelper(T &u_dot, const T2 &u_old, const T3 &u_older) const
Helper function that actually does the math for computing the time derivative.
virtual NumericVector< Number > * solutionUDot()=0
virtual Real & time() const
virtual bool converged(const unsigned int nl_sys_num)
Eventually we want to convert this virtual over to taking a nonlinear system number argument...
Definition: SubProblem.h:101
FEProblemBase & _fe_problem
void mooseInfo(Args &&... args) const
unsigned int _stage
DualNumber< Real, DNDerivativeType, true > DualReal
Definition: DualReal.h:49
NumericVector< Number > & _Re_non_time
residual vector for non-time contributions
SystemBase & _sys
The main MOOSE class responsible for handling user-defined parameters in almost every MOOSE system...
virtual void preSolve() override
virtual void advanceState()
Advance all of the state holding vectors / datastructures so that we can move to the next timestep...
const NumericVector< Number > & _solution_older
The older solution.
NumericVector< Number > & _residual_old
Buffer to store non-time residual from the first stage.
GHOSTED
registerMooseObject("MooseApp", ExplicitTVDRK2)
unsigned int _n_linear_iterations
Total number of linear iterations over all stages of the time step.
unsigned int number() const
Gets the number of this system.
Definition: SystemBase.C:1125
virtual void close()=0
Real & _du_dot_du
Derivative of time derivative with respect to current solution: .
const NumericVector< Number > *const & _solution
solution vectors
DIE A HORRIBLE DEATH HERE typedef LIBMESH_DEFAULT_SCALAR_TYPE Real
Base class for time integrators.
unsigned int getNumLinearIterationsLastSolve() const
Gets the number of linear iterations in the most recent solve.
void setConstJacobian(bool state)
Set flag that Jacobian is constant (for optimization purposes)
virtual System & system() override
Get the reference to the libMesh system.
ExplicitTVDRK2(const InputParameters &parameters)
void mooseError(Args &&... args) const
Emits an error prefixed with object name and type.
NumericVector< Number > & _Re_time
residual vector for time contributions
virtual void postResidual(NumericVector< Number > &residual) override
Callback to the TimeIntegrator called immediately after the residuals are computed in NonlinearSystem...
void addClassDescription(const std::string &doc_string)
This method adds a description of the class that will be displayed in the input file syntax dump...
virtual Real & timeOld() const
const NumericVector< Number > & _solution_old
unsigned int _n_nonlinear_iterations
Total number of nonlinear iterations over all stages of the time step.
const ConsoleStream _console
An instance of helper class to write streams to the Console objects.
unsigned int getNumNonlinearIterationsLastSolve() const
Gets the number of nonlinear iterations in the most recent solve.
Explicit TVD (total-variation-diminishing) second-order Runge-Kutta time integration methods: ...
virtual void solve() override
Solves the time step and sets the number of nonlinear and linear iterations.
virtual void add(const numeric_index_type i, const Number value)=0
static InputParameters validParams()
static InputParameters validParams()
void computeADTimeDerivatives(DualReal &ad_u_dot, const dof_id_type &dof, DualReal &ad_u_dotdot) const override
method for computing local automatic differentiation time derivatives
uint8_t dof_id_type