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// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-License-Identifier: BSD-3-Clause
/**
* @class vtkInitialValueProblemSolver
* @brief Integrate a set of ordinary
* differential equations (initial value problem) in time.
*
*
* Given a vtkFunctionSet which returns dF_i(x_j, t)/dt given x_j and
* t, vtkInitialValueProblemSolver computes the value of F_i at t+deltat.
*
* @warning
* vtkInitialValueProblemSolver and it's subclasses are not thread-safe.
* You should create a new integrator for each thread.
*
* @sa
* vtkRungeKutta2 vtkRungeKutta4
*/
#ifndef vtkInitialValueProblemSolver_h
#define vtkInitialValueProblemSolver_h
#include "vtkCommonMathModule.h" // For export macro
#include "vtkObject.h"
VTK_ABI_NAMESPACE_BEGIN
class vtkFunctionSet;
class VTKCOMMONMATH_EXPORT vtkInitialValueProblemSolver : public vtkObject
{
public:
vtkTypeMacro(vtkInitialValueProblemSolver, vtkObject);
void PrintSelf(ostream& os, vtkIndent indent) override;
///@{
/**
* Given initial values, xprev , initial time, t and a requested time
* interval, delT calculate values of x at t+delTActual (xnext).
* For certain concrete sub-classes delTActual != delT. This occurs
* when the solver supports adaptive stepsize control. If this
* is the case, the solver tries to change to stepsize such that
* the (estimated) error of the integration is less than maxError.
* The solver will not set the stepsize smaller than minStep or
* larger than maxStep.
* Also note that delT is an in/out argument. Adaptive solvers
* will modify delT to reflect the best (estimated) size for the next
* integration step.
* An estimated value for the error is returned (by reference) in error.
* Note that only some concrete sub-classes support this. Otherwise,
* the error is set to 0.
* This method returns an error code representing the nature of
* the failure:
* OutOfDomain = 1,
* NotInitialized = 2,
* UnexpectedValue = 3
*/
virtual int ComputeNextStep(
double* xprev, double* xnext, double t, double& delT, double maxError, double& error)
{
return this->ComputeNextStep(xprev, xnext, t, delT, maxError, error, nullptr);
}
virtual int ComputeNextStep(double* xprev, double* xnext, double t, double& delT, double maxError,
double& error, void* userData)
{
double minStep = delT;
double maxStep = delT;
double delTActual;
return this->ComputeNextStep(
xprev, nullptr, xnext, t, delT, delTActual, minStep, maxStep, maxError, error, userData);
}
virtual int ComputeNextStep(double* xprev, double* dxprev, double* xnext, double t, double& delT,
double maxError, double& error)
{
return this->ComputeNextStep(xprev, dxprev, xnext, t, delT, maxError, error, nullptr);
}
virtual int ComputeNextStep(double* xprev, double* dxprev, double* xnext, double t, double& delT,
double maxError, double& error, void* userData)
{
double minStep = delT;
double maxStep = delT;
double delTActual;
return this->ComputeNextStep(
xprev, dxprev, xnext, t, delT, delTActual, minStep, maxStep, maxError, error, userData);
}
virtual int ComputeNextStep(double* xprev, double* xnext, double t, double& delT,
double& delTActual, double minStep, double maxStep, double maxError, double& error)
{
return this->ComputeNextStep(
xprev, xnext, t, delT, delTActual, minStep, maxStep, maxError, error, nullptr);
}
virtual int ComputeNextStep(double* xprev, double* xnext, double t, double& delT,
double& delTActual, double minStep, double maxStep, double maxError, double& error,
void* userData)
{
return this->ComputeNextStep(
xprev, nullptr, xnext, t, delT, delTActual, minStep, maxStep, maxError, error, userData);
}
virtual int ComputeNextStep(double* xprev, double* dxprev, double* xnext, double t, double& delT,
double& delTActual, double minStep, double maxStep, double maxError, double& error)
{
return this->ComputeNextStep(
xprev, dxprev, xnext, t, delT, delTActual, minStep, maxStep, maxError, error, nullptr);
}
virtual int ComputeNextStep(double* vtkNotUsed(xprev), double* vtkNotUsed(dxprev),
double* vtkNotUsed(xnext), double vtkNotUsed(t), double& vtkNotUsed(delT),
double& vtkNotUsed(delTActual), double vtkNotUsed(minStep), double vtkNotUsed(maxStep),
double vtkNotUsed(maxError), double& vtkNotUsed(error), void* vtkNotUsed(userData))
{
return 0;
}
///@}
///@{
/**
* Set / get the dataset used for the implicit function evaluation.
*/
virtual void SetFunctionSet(vtkFunctionSet* fset);
vtkGetObjectMacro(FunctionSet, vtkFunctionSet);
///@}
/**
* Returns 1 if the solver uses adaptive stepsize control,
* 0 otherwise
*/
virtual vtkTypeBool IsAdaptive() { return this->Adaptive; }
enum ErrorCodes
{
OUT_OF_DOMAIN = 1,
NOT_INITIALIZED = 2,
UNEXPECTED_VALUE = 3
};
protected:
vtkInitialValueProblemSolver();
~vtkInitialValueProblemSolver() override;
virtual void Initialize();
vtkFunctionSet* FunctionSet;
double* Vals;
double* Derivs;
int Initialized;
vtkTypeBool Adaptive;
private:
vtkInitialValueProblemSolver(const vtkInitialValueProblemSolver&) = delete;
void operator=(const vtkInitialValueProblemSolver&) = delete;
};
VTK_ABI_NAMESPACE_END
#endif
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