OffLatticeRandomFieldGenerator.cpp

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#include "OffLatticeRandomFieldGenerator.hpp"
 
#include <algorithm>
#include <iomanip>
#include <fstream>
#include <memory>
#include <numeric>
 
#include "Exception.hpp"
#include "RandomNumberGenerator.hpp"
#include "RandomFieldUtilityFunctions.hpp"
 
template <unsigned SPACE_DIM>
OffLatticeRandomFieldGenerator<SPACE_DIM>::OffLatticeRandomFieldGenerator(
    std::array<double, SPACE_DIM> lowerCorner,
    std::array<double, SPACE_DIM> upperCorner,
    std::array<bool, SPACE_DIM> periodicity,
    double lengthScale,
    double boxWidth)
    : mLowerCorner(lowerCorner),
      mUpperCorner(upperCorner),
      mPeriodicity(periodicity),
      mLengthScale(lengthScale),
      mpBoxCollection(nullptr)
{
    // Reset the box width if the default value is being used
    if (boxWidth == DOUBLE_UNSET)
    {
        const double max_box_width = 4.0 * lengthScale;
        boxWidth = std::min(max_box_width, upperCorner[0] - lowerCorner[0]);
    }
 
    // Set up the box collection
    c_vector<double, 2 * SPACE_DIM> domain_size;
    for (unsigned dim = 0; dim < SPACE_DIM; ++dim)
    {
        domain_size[2 * dim] = lowerCorner[dim];
        domain_size[2 * dim + 1] = upperCorner[dim];
    }
 
    bool periodic_x = periodicity[0];
    bool periodic_y = SPACE_DIM > 1 ? periodicity[1] : false;
    bool periodic_z = SPACE_DIM > 2 ? periodicity[2] : false;
 
    mpBoxCollection = std::make_unique<ObsoleteBoxCollection<SPACE_DIM>>(
        boxWidth,
        domain_size,
        periodic_x,
        periodic_y,
        periodic_z
    );
 
    mpBoxCollection->SetupLocalBoxesHalfOnly();
    mOpenSimplex = OpenSimplex2S();
}
 
template <unsigned SPACE_DIM>
void OffLatticeRandomFieldGenerator<SPACE_DIM>::SetRandomSeed(
    const unsigned seed)
{
    mOpenSimplex = OpenSimplex2S(seed);
}
 
template <unsigned SPACE_DIM>
std::vector<double> OffLatticeRandomFieldGenerator<SPACE_DIM>::SampleRandomField(
    const std::vector<Node<SPACE_DIM>*>& rNodes)
{
    return this->SampleRandomFieldAtTime(rNodes, 100.0 * mLengthScale * RandomNumberGenerator::Instance()->ranf());
}
 
template <unsigned SPACE_DIM>
std::vector<double> OffLatticeRandomFieldGenerator<SPACE_DIM>::SampleRandomFieldAtTime(
    const std::vector<Node<SPACE_DIM>*>& rNodes,
    const double time)
{
    std::vector<double> samples(rNodes.size());
    for (unsigned i = 0; i < samples.size(); ++i)
    {
        const c_vector<double, SPACE_DIM> node_location = rNodes[i]->rGetLocation();
        switch (SPACE_DIM)
        {
            case 1:
            {
                samples[i] = random_field::Reshape(mOpenSimplex.noise2_XBeforeY(node_location[0] * mLengthScale, time + 0.5));
                break;
            }
            case 2:
            {
                samples[i] = random_field::Reshape(mOpenSimplex.noise3_XYBeforeZ(node_location[0] * mLengthScale, node_location[1] * mLengthScale, time));
                break;
            }
            case 3:
            {
                samples[i] = random_field::Reshape(mOpenSimplex.noise4_XYBeforeZW(node_location[0] * mLengthScale, node_location[1] * mLengthScale, node_location[2] * mLengthScale, time));
                break;
            }
            default:
                // This can't happen
                NEVER_REACHED;
        }
    }
 
    return samples;
}
// Explicit instantiation
template class OffLatticeRandomFieldGenerator<1>;
template class OffLatticeRandomFieldGenerator<2>;
template class OffLatticeRandomFieldGenerator<3>;