Description
Implementation of the HHT implicit integrator for II order systems.
This timestepper allows use of an adaptive time-step, as well as optional use of a modified Newton scheme for the solution of the resulting nonlinear problem.
#include <ChTimestepperHHT.h>


Public Member Functions | |
| ChTimestepperHHT (ChIntegrableIIorder *intgr=nullptr) | |
| virtual Type | GetType () const override |
| Return type of the integration method. | |
| void | SetAlpha (double val) |
| Set the numerical damping parameter (in the [-1/3, 0] range). | |
| double | GetAlpha () |
| Return the current value of the method parameter alpha. | |
| void | SetStepControl (bool enable) |
| Turn on/off the internal step size control. | |
| void | SetMinStepSize (double step) |
| Set the minimum step size. | |
| void | SetMaxItersSuccess (int iters) |
| Set the maximum allowable number of iterations for counting a step towards a stepsize increase. | |
| void | SetRequiredSuccessfulSteps (int num_steps) |
| Set the minimum number of (internal) steps that use at most maxiters_success before considering a stepsize increase. | |
| void | SetStepIncreaseFactor (double factor) |
| Set the multiplicative factor for a stepsize increase (must be larger than 1). | |
| void | SetStepDecreaseFactor (double factor) |
| Set the multiplicative factor for a stepsize decrease (must be smaller than 1). | |
| void | SetModifiedNewton (bool enable) |
| Enable/disable modified Newton. | |
| virtual void | Advance (const double dt) override |
| Perform an integration timestep, by advancing the state by the specified time step. | |
| double | GetEstimatedConvergenceRate () const |
| Get the last estimated convergence rate for the internal Newton solver. | |
| virtual void | ArchiveOut (ChArchiveOut &archive) override |
| Method to allow serialization of transient data to archives. | |
| virtual void | ArchiveIn (ChArchiveIn &archive) override |
| Method to allow de-serialization of transient data from archives. | |
Public Member Functions inherited from chrono::ChTimestepperIIorder | |
| ChTimestepperIIorder (ChIntegrableIIorder *intgr=nullptr) | |
| Constructor. | |
| virtual | ~ChTimestepperIIorder () |
| Destructor. | |
| virtual ChState & | GetStatePos () |
| Access the state, position part, at current time. | |
| virtual ChStateDelta & | GetStateVel () |
| Access the state, speed part, at current time. | |
| virtual ChStateDelta & | GetStateAcc () |
| Access the acceleration, at current time. | |
| virtual void | SetIntegrable (ChIntegrableIIorder *intgr) |
| Set the integrable object. | |
Public Member Functions inherited from chrono::ChTimestepper | |
| ChTimestepper (ChIntegrable *intgr=nullptr) | |
| Constructor. | |
| virtual | ~ChTimestepper () |
| Destructor. | |
| virtual ChVectorDynamic & | GetLagrangeMultipliers () |
| Access the lagrangian multipliers, if any. | |
| ChIntegrable * | GetIntegrable () |
| Get the integrable object. | |
| virtual double | GetTime () const |
| Get the current time. | |
| virtual void | SetTime (double mt) |
| Set the current time. | |
| void | SetVerbose (bool verb) |
| Turn on/off logging of messages. | |
Public Member Functions inherited from chrono::ChImplicitIterativeTimestepper | |
| void | SetMaxIters (int iters) |
| Set the max number of iterations using the Newton Raphson procedure. | |
| double | GetMaxIters () |
| Get the max number of iterations using the Newton Raphson procedure. | |
| void | SetRelTolerance (double rel_tol) |
| Set the relative tolerance. | |
| void | SetAbsTolerances (double abs_tolS, double abs_tolL) |
| Set the absolute tolerances. | |
| void | SetAbsTolerances (double abs_tol) |
| Set the absolute tolerances. | |
| unsigned int | GetNumIterations () const |
| Return the number of iterations. | |
| unsigned int | GetNumSetupCalls () const |
| Return the number of calls to the solver's Setup function. | |
| unsigned int | GetNumSolveCalls () const |
| Return the number of calls to the solver's Solve function. | |
Additional Inherited Members | |
Public Types inherited from chrono::ChTimestepper | |
| enum class | Type { EULER_IMPLICIT_LINEARIZED = 0 , EULER_IMPLICIT_PROJECTED = 1 , EULER_IMPLICIT = 2 , TRAPEZOIDAL = 3 , TRAPEZOIDAL_LINEARIZED = 4 , HHT = 5 , HEUN = 6 , RUNGEKUTTA45 = 7 , EULER_EXPLICIT = 8 , LEAPFROG = 9 , NEWMARK = 10 , CUSTOM = 20 } |
| Available methods for time integration (time steppers). | |
Protected Attributes inherited from chrono::ChTimestepperIIorder | |
| ChState | X |
| ChStateDelta | V |
| ChStateDelta | A |
Protected Attributes inherited from chrono::ChTimestepper | |
| ChIntegrable * | integrable |
| double | T |
| ChVectorDynamic | L |
| bool | verbose |
| bool | Qc_do_clamp |
| double | Qc_clamping |
Protected Attributes inherited from chrono::ChImplicitIterativeTimestepper | |
| unsigned int | maxiters |
| maximum number of iterations | |
| double | reltol |
| relative tolerance | |
| double | abstolS |
| absolute tolerance (states) | |
| double | abstolL |
| absolute tolerance (Lagrange multipliers) | |
| unsigned int | numiters |
| number of iterations | |
| unsigned int | numsetups |
| number of calls to the solver's Setup function | |
| unsigned int | numsolves |
| number of calls to the solver's Solve function | |
Member Function Documentation
◆ Advance()
|
overridevirtual |
Perform an integration timestep, by advancing the state by the specified time step.
Implements chrono::ChTimestepper.
◆ ArchiveIn()
|
overridevirtual |
Method to allow de-serialization of transient data from archives.
Reimplemented from chrono::ChTimestepper.
◆ ArchiveOut()
|
overridevirtual |
Method to allow serialization of transient data to archives.
Reimplemented from chrono::ChTimestepper.
◆ GetEstimatedConvergenceRate()
|
inline |
Get the last estimated convergence rate for the internal Newton solver.
Note that an estimate can only be calculated after the 3rd iteration. For the first 2 iterations, the convergence rate estimate is set to 1.
◆ GetType()
|
inlineoverridevirtual |
Return type of the integration method.
Reimplemented from chrono::ChTimestepper.
◆ SetAlpha()
| void chrono::ChTimestepperHHT::SetAlpha | ( | double | val | ) |
Set the numerical damping parameter (in the [-1/3, 0] range).
The closer to -1/3, the more damping. The closer to 0, the less damping (for 0, it is the trapezoidal method). The method coefficients gamma and beta are set automatically, based on alpha. Default: -0.2.
◆ SetMaxItersSuccess()
|
inline |
Set the maximum allowable number of iterations for counting a step towards a stepsize increase.
Default: 3.
◆ SetMinStepSize()
|
inline |
Set the minimum step size.
An exception is thrown if the internal step size decreases below this limit. Default: 1e-10.
◆ SetModifiedNewton()
|
inline |
Enable/disable modified Newton.
If enabled, the Newton matrix is evaluated, assembled, and factorized only once per step or if the Newton iteration does not converge with an out-of-date matrix. If disabled, the Newton matrix is evaluated at every iteration of the nonlinear solver. Default: true.
◆ SetRequiredSuccessfulSteps()
|
inline |
Set the minimum number of (internal) steps that use at most maxiters_success before considering a stepsize increase.
Default: 5.
◆ SetStepControl()
|
inline |
Turn on/off the internal step size control.
Default: true.
◆ SetStepDecreaseFactor()
|
inline |
Set the multiplicative factor for a stepsize decrease (must be smaller than 1).
Default: 0.5.
◆ SetStepIncreaseFactor()
|
inline |
Set the multiplicative factor for a stepsize increase (must be larger than 1).
Default: 2.
The documentation for this class was generated from the following files:
- C:/M/B/src/chrono-9.0.1/src/chrono/timestepper/ChTimestepperHHT.h
- C:/M/B/src/chrono-9.0.1/src/chrono/timestepper/ChTimestepperHHT.cpp
Public Member Functions inherited from