kernel.h

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///////////////////////////////////////////////////////////////////////////////
//
// File: kernel.h
//
// For more information, please see: http://www.nektar.info
//
// The MIT License
//
// Copyright (c) 2006 Scientific Computing and Imaging Institute,
// University of Utah (USA) and Department of Aeronautics, Imperial
// College London (UK).
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//
// Description:
//
///////////////////////////////////////////////////////////////////////////////
 
#ifndef NEKTAR_LIB_UTILIITIES_KERNEL_KERNEL_H
#define NEKTAR_LIB_UTILIITIES_KERNEL_KERNEL_H
 
#include <LibUtilities/BasicConst/NektarUnivConsts.hpp>
#include <LibUtilities/BasicUtils/SharedArray.hpp>
#include <LibUtilities/LibUtilitiesDeclspec.h>
 
namespace Nektar
{
namespace LibUtilities
{
class Kernel
{
public:
    /**
     * \brief The default constructor
     */
    LIB_UTILITIES_EXPORT Kernel();
 
    LIB_UTILITIES_EXPORT Kernel(int order);
 
    /**
     * \brief The default destructor
     */
    //~Kernel();
 
    /**
     * \brief This funciton updates the bspline to the appropriate order.
     */
    LIB_UTILITIES_EXPORT void UpdateKernelBspline();
 
    /**
     * \brief This funciton updates the kernel coefficients.
     */
    LIB_UTILITIES_EXPORT void UpdateKernelCoeffs();
 
    /**
     * \brief This funciton updates the kernel breaks.
     * \param h represents the mesh spacing
     */
    LIB_UTILITIES_EXPORT void UpdateKernelBreaks(NekDouble h);
 
    /**
     * \brief This funciton returns a 2D array representing the bspline
     *  of the appropriate order.
     */
    Array<TwoD, NekDouble> GetKernelBspline()
    {
        return b_spline;
    }
 
    /**
     * \brief This funciton returns a 1D array representing the kernel
     * coefficients
     */
    Array<OneD, NekDouble> GetKernelCoeffs()
    {
        return k_coeffs;
    }
 
    /**
     * \brief This funciton returns a 1D array representing the kernel breaks
     */
    Array<OneD, NekDouble> GetKernelBreaks()
    {
        return k_breaks;
    }
 
    /**
     * \brief This funciton sets the k_order variable
     */
    void UpdateKernelOrder(int order)
    {
        k_order = order;
    }
 
    /**
     * \brief This funciton sets the k_ncoeffs variable
     */
    void UpdateKernelNumOfCoeffs()
    {
        k_ncoeffs = 2 * (k_order - 1) + 1;
    }
 
    /**
     * \brief This funciton sets the kernel width size
     */
    void UpdateKernelWidth()
    {
        k_width = 3 * (k_order - 1) + 1;
    }
 
    /**
     * \brief This funciton returns the order of the kernel
     */
    int GetKernelOrder()
    {
        return k_order;
    }
 
    /**
     * \brief This funciton returns the number of kernel coefficients
     */
    int GetKernelNumeOfCoeffs()
    {
        return k_ncoeffs;
    }
 
    /**
     * \brief This funciton returns the size of the kernel width
     */
    int GetKernelWidth()
    {
        return k_width;
    }
 
    /**
     * \brief This funciton moves the center of the kernel to the
       \param x_value.
       \param outarray is used to store the result
     */
    LIB_UTILITIES_EXPORT void MoveKernelCenter(
        NekDouble x_value, Array<OneD, NekDouble> &outarray);
 
    /**
     * \brief This funciton calculates the mesh breaks under the kernel support
       \param inarray contains the local kernel breaks
       \param h is the mesh spacing
       \param outarray contains the coordinate of the mesh breaks under the
     kernel support
     */
    LIB_UTILITIES_EXPORT void FindMeshUnderKernel(
        Array<OneD, NekDouble> &inarray, NekDouble h,
        Array<OneD, NekDouble> &outarray);
 
    /**
     * \brief This funciton evaluates the kernel at input values
       \param inarray.
       \param h is the mesh spacing.
       \param outarray contains the kernel values
     */
    LIB_UTILITIES_EXPORT void EvaluateKernel(Array<OneD, NekDouble> inarray,
                                             NekDouble h,
                                             Array<OneD, NekDouble> &outarray);
 
    /**
     * \brief This function evaluates the bspline at input values
       \param inarray               input values.
       \param h                     the mesh spacing.
       \param offset
       \param outarray              contains the bspline values.
     */
    LIB_UTILITIES_EXPORT void EvaluateBspline(Array<OneD, NekDouble> inarray,
                                              NekDouble h, NekDouble offset,
                                              Array<OneD, NekDouble> &outarray);
 
    /**
     * \brief This funciton performs the ordered merge of \param inarray1
     * and \param inarray2 and puts the result in \param outarray
     */
    LIB_UTILITIES_EXPORT void Sort(Array<OneD, NekDouble> &inarray1,
                                   Array<OneD, NekDouble> &inarray2,
                                   Array<OneD, NekDouble> &outarray);
 
protected:
    int k_order;   /**< bsplines are obtained by convolving the characteristic
                                            fucntion with itself (k_order - 1)
                      times */
    int k_ncoeffs; /**< Represents the number of kernel coefficients */
    int k_width;   /**< Represents the width of the kernel */
    NekDouble k_center;              /**< holds the center of the kernel */
    Array<TwoD, NekDouble> b_spline; /**< 2D array representing the bspline */
    Array<OneD, NekDouble>
        k_coeffs; /**< 1D array representing the kernel coefficients */
    Array<OneD, NekDouble>
        k_breaks; /**< 1D array representing the kernel breaks */
 
    /**
     * \brief This funciton evaluates the piecewise bspline polynomial
       \param interval \param interval at point \param x_value.
     */
    NekDouble EvaluateBsplinePoly(NekDouble x_value, int interval);
 
private:
};
 
typedef std::shared_ptr<Kernel> KernelSharedPtr;
 
} // namespace LibUtilities
} // namespace Nektar
 
#endif // NEKTAR_LIB_UTILIITIES_KERNEL_KERNEL_H