MeshUtilityFunctions.cpp

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*/
 
#include "MeshUtilityFunctions.hpp"
 
#include "RandomNumberGenerator.hpp"
 
#include <algorithm>
#include <cassert>
 
template <std::size_t DIM>
std::vector<c_vector<double, DIM>> EvenlySpaceAlongPath(
        std::vector<c_vector<double, DIM>>& path,
        const bool closedPath,
        const bool permuteOrder,
        std::size_t numPointsToPlace,
        const double targetSpacing
)
{
    assert(!path.empty());
    assert(numPointsToPlace > 0 || targetSpacing < DBL_MAX);
 
    if (closedPath)
    {
        if (permuteOrder)
        {
            // Rotate the closed path around a random pivot so we start at a random location along it
            const unsigned random_pivot = RandomNumberGenerator::Instance()->randMod(path.size());
            std::rotate(path.begin(), path.begin() + random_pivot, path.end());
        }
 
        path.emplace_back(path.front());
    }
 
    // Calculate a vector of edge vectors, and a vector of edge lengths
    std::vector<c_vector<double, DIM>> edge_unit_vectors;
    edge_unit_vectors.reserve(path.size() - 1);
 
    std::vector<double> edge_length_partial_sums;
    edge_length_partial_sums.reserve(path.size() - 1);
 
    for (unsigned i = 1; i < path.size(); ++i)
    {
        const c_vector<double, DIM> un_normalised_vec = path[i] - path[i - 1];
        const double edge_length = norm_2(un_normalised_vec);
 
        edge_unit_vectors.emplace_back(un_normalised_vec / edge_length);
 
        if (edge_length_partial_sums.empty())
        {
            edge_length_partial_sums.emplace_back(edge_length);
        }
        else
        {
            edge_length_partial_sums.emplace_back(edge_length_partial_sums.back() + edge_length);
        }
    }
 
    // Calculate the spacing, allowing the targetSpacing to override the number of points to place.
    // If the path is open, we want to hit the start and end, so subtract one from the numPointsToPlace.
    if (targetSpacing < DBL_MAX)
    {
        numPointsToPlace = static_cast<unsigned>(!closedPath + std::ceil(edge_length_partial_sums.back() / targetSpacing));
    }
    const double spacing = edge_length_partial_sums.back() / (numPointsToPlace - static_cast<unsigned>(!closedPath));
 
    // The vector of new locations to add to
    std::vector<c_vector<double, DIM>> new_locations;
    new_locations.reserve(numPointsToPlace);
 
    double remainder = 0.0;
    for (unsigned edge = 0; edge < edge_length_partial_sums.size(); ++edge)
    {
        unsigned new_locs_this_edge = 0u;
        while(spacing * new_locations.size() < edge_length_partial_sums[edge])
        {
            new_locations.emplace_back(path[edge] + (new_locs_this_edge * spacing - remainder) * edge_unit_vectors[edge]);
            new_locs_this_edge++;
        }
        remainder = edge_length_partial_sums[edge] - spacing * new_locations.size();
    }
 
    if (!closedPath)
    {
        new_locations.emplace_back(path.back());
    }
 
    return new_locations;
}
 
// Explicit instantiation
template std::vector<c_vector<double, 1>> EvenlySpaceAlongPath(std::vector<c_vector<double, 1>>&, bool, bool, std::size_t, double);
template std::vector<c_vector<double, 2>> EvenlySpaceAlongPath(std::vector<c_vector<double, 2>>&, bool, bool, std::size_t, double);
template std::vector<c_vector<double, 3>> EvenlySpaceAlongPath(std::vector<c_vector<double, 3>>&, bool, bool, std::size_t, double);