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/*=========================================================================
Program: Visualization Toolkit
Module: vtkSPHQuarticKernel.h
Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
All rights reserved.
See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
This software is distributed WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the above copyright notice for more information.
=========================================================================*/
/**
* @class vtkSPHQuarticKernel
* @brief a quartic SPH interpolation kernel
*
*
* vtkSPHQuarticKernel is an smooth particle hydrodynamics interpolation kernel as
* described by D.J. Price. This is a quartic formulation.
*
* @warning
* For more information see D.J. Price, Smoothed particle hydrodynamics and
* magnetohydrodynamics, J. Comput. Phys. 231:759-794, 2012. Especially
* equation 49.
*
* @par Acknowledgments:
* The following work has been generously supported by Altair Engineering
* and FluiDyna GmbH. Please contact Steve Cosgrove or Milos Stanic for
* more information.
*
* @sa
* vtkSPHKernel vtkSPHInterpolator
*/
#ifndef vtkSPHQuarticKernel_h
#define vtkSPHQuarticKernel_h
#include "vtkFiltersPointsModule.h" // For export macro
#include "vtkSPHKernel.h"
#include <algorithm> // For std::min()
class vtkIdList;
class vtkDoubleArray;
class VTKFILTERSPOINTS_EXPORT vtkSPHQuarticKernel : public vtkSPHKernel
{
public:
//@{
/**
* Standard methods for instantiation, obtaining type information, and printing.
*/
static vtkSPHQuarticKernel* New();
vtkTypeMacro(vtkSPHQuarticKernel, vtkSPHKernel);
void PrintSelf(ostream& os, vtkIndent indent) override;
//@}
/**
* Produce the computational parameters for the kernel. Invoke this method
* after setting initial values like SpatialStep.
*/
void Initialize(vtkAbstractPointLocator* loc, vtkDataSet* ds, vtkPointData* pd) override;
//@{
/**
* Compute weighting factor given a normalized distance from a sample point.
*/
double ComputeFunctionWeight(const double d) override
{
double tmp1 = 2.5 - std::min(d, 2.5);
double tmp2 = 1.5 - std::min(d, 1.5);
double tmp3 = 0.5 - std::min(d, 0.5);
return (tmp1 * tmp1 * tmp1 * tmp1 - 5.0 * tmp2 * tmp2 * tmp2 * tmp2 +
10.0 * tmp3 * tmp3 * tmp3 * tmp3);
}
//@}
//@{
/**
* Compute weighting factor for derivative quantities given a normalized
* distance from a sample point.
*/
double ComputeDerivWeight(const double d) override
{
double tmp1 = 2.5 - std::min(d, 2.5);
double tmp2 = 1.5 - std::min(d, 1.5);
double tmp3 = 0.5 - std::min(d, 0.5);
return (-4.0 * tmp1 * tmp1 * tmp1 + 20.0 * tmp2 * tmp2 * tmp2 - 40.0 * tmp3 * tmp3 * tmp3);
}
//@}
protected:
vtkSPHQuarticKernel();
~vtkSPHQuarticKernel() override;
private:
vtkSPHQuarticKernel(const vtkSPHQuarticKernel&) = delete;
void operator=(const vtkSPHQuarticKernel&) = delete;
};
#endif