Octree.h

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////////////////////////////////////////////////////////////////////////////////
//
//  File: Octree.h
//
//  For more information, please see: http://www.nektar.info/
//
//  The MIT License
//
//  Copyright (c) 2006 Division of Applied Mathematics, Brown University (USA),
//  Department of Aeronautics, Imperial College London (UK), and Scientific
//  Computing and Imaging Institute, University of Utah (USA).
//
//  License for the specific language governing rights and limitations under
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//  copy of this software and associated documentation files (the "Software"),
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//
//  Description: octree object header
//
////////////////////////////////////////////////////////////////////////////////

#ifndef NEKTAR_MESHUTILS_OCTREE_OCTREE
#define NEKTAR_MESHUTILS_OCTREE_OCTREE

#include <boost/shared_ptr.hpp>

#include <NekMeshUtils/CADSystem/CADSystem.h>
#include <NekMeshUtils/Octree/CurvaturePoint.hpp>
#include <NekMeshUtils/Octree/Octant.h>
#include <NekMeshUtils/MeshElements/Mesh.h>

#include <LibUtilities/BasicUtils/SharedArray.hpp>
#include <LibUtilities/Memory/NekMemoryManager.hpp>

namespace Nektar
{
namespace NekMeshUtils
{

/**
 * @brief class for octree
 *
 * This class contains the routines to generate and query a automatically
 * generated set of mesh spacing parameters based on the CAD
 */
class Octree
{
public:
    friend class MemoryManager<Octree>;

    /**
     * @brief Defualt constructor
     *
     * @param cad CAD object
     * @param ver bool verbose
     */
    Octree(CADSystemSharedPtr cad,
           const bool ver,
           const NekDouble min,
           const NekDouble max,
           const NekDouble eps,
           const std::string uds)
        : m_minDelta(min), m_maxDelta(max), m_eps(eps), m_cad(cad),
          m_verbose(ver), m_udsfile(uds)
    {
    }

    /**
     * @brief executes octree building routines
     */
    void Build();

    /**
     * @brief once constructed queryies the octree based on x,y,z location
     * to get a mesh spacing
     *
     * @param loc array of x,y,z
     * @return mesh spacing parameter
     */
    NekDouble Query(Array<OneD, NekDouble> loc);

    /**
     * @brief returns the miminum spacing in the octree (for meshing purposes)
     *
     * @return miminum delta in octree
     */
    NekDouble GetMinDelta()
    {
        return m_minDelta;
    }

    /**
     * @brief populates the mesh m with a invalid hexahedral mesh based on the
     *        octree, used for visualisation
     */
    void GetOctreeMesh(MeshSharedPtr m);

private:
    /**
     * @brief Smooths specification over all octants to a gradation criteria
     */
    void SmoothAllOctants();

    /**
     * @brief gets an optimum number of curvature sampling points and
     * calculates the curavture at these points
     */
    void CompileCuravturePointList();

    /**
     * @brief Function which initiates and controls the subdivision process
     */
    void SubDivide();

    /**
     * @brief Smooths specification over the surface encompasing octants to a
     *        gradation criteria
     */
    void SmoothSurfaceOctants();

    /**
     * @brief takes the mesh specification from surface octants and
     *        progates that through the domain so all octants have a
     * specification
     *        using gradiation crieteria
     */
    void PropagateDomain();

    /**
     * @brief estimates the number of elements to be created in the mesh
     */
    int CountElemt();

    /**
     * @brief Calculates the difference in delta divided by the difference
     *        in location between two octants i and j
     */
    NekDouble ddx(OctantSharedPtr i, OctantSharedPtr j);

    /**
     * @brief Looks over all leaf octants and checks that their neigbour
     *        assigments are valid
     */
    bool VerifyNeigbours();

    /// minimum delta in the octree
    NekDouble m_minDelta;
    /// maximum delta in the octree
    NekDouble m_maxDelta;
    /// curavture sensivity paramter
    NekDouble m_eps;
    /// cad object
    CADSystemSharedPtr m_cad;
    /// verbose output
    bool m_verbose;
    /// x,y,z location of the center of the octree
    Array<OneD, NekDouble> m_centroid;
    /// physical size of the octree
    NekDouble m_dim;
    /// list of curvature sample points
    std::vector<CurvaturePointSharedPtr> m_cpList;
    /// list of leaf octants
    std::vector<OctantSharedPtr> m_octants;
    /// master octant for searching
    OctantSharedPtr m_masteroct;
    /// number of octants made, used for id index
    int m_numoct;

    std::string m_udsfile;
};

typedef boost::shared_ptr<Octree> OctreeSharedPtr;
}
}

#endif