HoneycombVertexMeshGenerator.cpp

/*

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*/

#include "HoneycombVertexMeshGenerator.hpp"

HoneycombVertexMeshGenerator::HoneycombVertexMeshGenerator(unsigned numElementsAcross,
                                                           unsigned numElementsUp,
                                                           bool isFlatBottom,
                                                           double cellRearrangementThreshold,
                                                           double t2Threshold,
                                                           double elementArea)
{
    assert(numElementsAcross > 0);
    assert(numElementsUp > 0);
    assert(cellRearrangementThreshold > 0.0);
    assert(t2Threshold > 0.0);
    assert(elementArea > 0.0);

    std::vector<Node<2>*> nodes;
    std::vector<VertexElement<2,2>*>  elements;

    unsigned node_index = 0;
    unsigned node_indices[6];
    unsigned element_index;

    // Create the nodes, row by row, from the bottom up

    // On the first row we have numElementsAcross nodes, all of which are boundary nodes
    for (unsigned i=0; i<numElementsAcross; i++)
    {
        Node<2>* p_node = new Node<2>(node_index, true, i+0.5, 0);
        nodes.push_back(p_node);
        node_index++;
    }

    /*
     * On each interior row we have numElementsAcross+1 nodes. On the second and penultimate
     * row all nodes are boundary nodes. On other rows the first and last nodes only
     * are boundary nodes.
     */
    for (unsigned j=1; j<2*numElementsUp+1; j++)
    {
        for (unsigned i=0; i<=numElementsAcross; i++)
        {
            double x_coord = ((j%4 == 0)||(j%4 == 3)) ? i+0.5 : i;
            double y_coord = (1.5*j - 0.5*(j%2))*0.5/sqrt(3.0);
            bool is_boundary_node = (j==1 || j==2*numElementsUp || i==0 || i==numElementsAcross) ? true : false;

            Node<2>* p_node = new Node<2>(node_index, is_boundary_node, x_coord, y_coord);
            nodes.push_back(p_node);
            node_index++;
        }
    }

    /*
     * On the last row we have numElementsAcross nodes, all of which are boundary nodes.
     */
    double y_coord = (1.5*(2*numElementsUp+1) - 0.5*((2*numElementsUp+1)%2))*0.5/sqrt(3.0);
    if (((2*numElementsUp+1)%4 == 0)||((2*numElementsUp+1)%4 == 3))
    {
        Node<2>* p_node = new Node<2>(node_index, true, 0.5, y_coord);
        nodes.push_back(p_node);
        node_index++;
    }
    for (unsigned i=1; i<numElementsAcross; i++)
    {
        double x_coord = (((2*numElementsUp+1)%4 == 0)||((2*numElementsUp+1)%4 == 3)) ? i+0.5 : i;

        Node<2>* p_node = new Node<2>(node_index, true, x_coord, y_coord);
        nodes.push_back(p_node);
        node_index++;
    }
    if (((2*numElementsUp+1)%4 == 1)||((2*numElementsUp+1)%4 == 2))
    {
        Node<2>* p_node = new Node<2>(node_index, true, numElementsAcross, y_coord);
        nodes.push_back(p_node);
        node_index++;
    }

    /*
     * Create the elements. The array node_indices contains the
     * global node indices from bottom, going anticlockwise.
     */
    for (unsigned j=0; j<numElementsUp; j++)
    {
        for (unsigned i=0; i<numElementsAcross; i++)
        {
            if (j==0)
            {
                node_indices[0] = i;
            }
            else
            {
                node_indices[0] = 2*j*(numElementsAcross+1) - 1*(j%2==0) + i; // different for even/odd rows
            }
            node_indices[1] = node_indices[0] + numElementsAcross + 1 + 1*(j%2==0 && j>0);
            node_indices[2] = node_indices[1] + numElementsAcross + 1;
            node_indices[3] = node_indices[2] + numElementsAcross + 1*(j%2==1 && j<numElementsUp-1);
            node_indices[4] = node_indices[2] - 1;
            node_indices[5] = node_indices[1] - 1;

            std::vector<Node<2>*> element_nodes;
            for (unsigned k=0; k<6; k++)
            {
               element_nodes.push_back(nodes[node_indices[k]]);
            }

            element_index = j*numElementsAcross + i;
            VertexElement<2,2>* p_element = new VertexElement<2,2>(element_index, element_nodes);
            elements.push_back(p_element);
        }
    }

    mpMesh = new MutableVertexMesh<2,2>(nodes, elements, cellRearrangementThreshold, t2Threshold);

    // Scale the mesh so that each element's area takes the value elementArea
    mpMesh->Scale(sqrt(elementArea*2.0/sqrt(3.0)), sqrt(elementArea*2.0/sqrt(3.0)));
}

HoneycombVertexMeshGenerator::~HoneycombVertexMeshGenerator()
{
    delete mpMesh;
}

MutableVertexMesh<2,2>* HoneycombVertexMeshGenerator::GetMesh()
{
    return mpMesh;
}