CrossedTrackSplittingAlgorithm.cc

Go to the documentation of this file.

/**
 *  @file   larpandoracontent/LArTwoDReco/LArClusterSplitting/CrossedTrackSplittingAlgorithm.cc
 *
 *  @brief  Implementation of the crossed track splitting algorithm class.
 *
 *  $Log: $
 */

#include "Pandora/AlgorithmHeaders.h"

#include "larpandoracontent/LArHelpers/LArClusterHelper.h"
#include "larpandoracontent/LArHelpers/LArPointingClusterHelper.h"

#include "larpandoracontent/LArTwoDReco/LArClusterSplitting/CrossedTrackSplittingAlgorithm.h"

#include "larpandoracontent/LArUtility/KDTreeLinkerAlgoT.h"

using namespace pandora;

namespace lar_content
{

CrossedTrackSplittingAlgorithm::CrossedTrackSplittingAlgorithm() :
    m_maxClusterSeparation(2.f),
    m_maxClusterSeparationSquared(m_maxClusterSeparation * m_maxClusterSeparation),
    m_minCosRelativeAngle(0.966f),
    m_searchRegion1D(2.f)
{
}

//------------------------------------------------------------------------------------------------------------------------------------------

StatusCode CrossedTrackSplittingAlgorithm::PreparationStep(const ClusterVector &clusterVector)
{
    // ATTN Don't need to update nearby cluster map after cluster merges because algorithm does not revisit processed clusters
    HitToClusterMap hitToClusterMap;
    CaloHitList allCaloHits;

    for (const Cluster *const pCluster : clusterVector)
    {
        CaloHitList daughterHits;
        pCluster->GetOrderedCaloHitList().FillCaloHitList(daughterHits);
        allCaloHits.insert(allCaloHits.end(), daughterHits.begin(), daughterHits.end());

        for (const CaloHit *const pCaloHit : daughterHits)
            (void)hitToClusterMap.insert(HitToClusterMap::value_type(pCaloHit, pCluster));
    }

    HitKDTree2D kdTree;
    HitKDNode2DList hitKDNode2DList;

    KDTreeBox hitsBoundingRegion2D(fill_and_bound_2d_kd_tree(allCaloHits, hitKDNode2DList));
    kdTree.build(hitKDNode2DList, hitsBoundingRegion2D);

    for (const Cluster *const pCluster : clusterVector)
    {
        CaloHitList daughterHits;
        pCluster->GetOrderedCaloHitList().FillCaloHitList(daughterHits);

        for (const CaloHit *const pCaloHit : daughterHits)
        {
            KDTreeBox searchRegionHits(build_2d_kd_search_region(pCaloHit, m_searchRegion1D, m_searchRegion1D));

            HitKDNode2DList found;
            kdTree.search(searchRegionHits, found);

            for (const auto &hit : found)
                (void)m_nearbyClusters[pCluster].insert(hitToClusterMap.at(hit.data));
        }
    }

    return STATUS_CODE_SUCCESS;
}

//------------------------------------------------------------------------------------------------------------------------------------------

StatusCode CrossedTrackSplittingAlgorithm::TidyUpStep()
{
    m_nearbyClusters.clear();

    return STATUS_CODE_SUCCESS;
}

//------------------------------------------------------------------------------------------------------------------------------------------

StatusCode CrossedTrackSplittingAlgorithm::FindBestSplitPosition(const TwoDSlidingFitResult &slidingFitResult1,
    const TwoDSlidingFitResult &slidingFitResult2, CartesianVector &splitPosition, CartesianVector &firstDirection, CartesianVector &secondDirection) const
{
    // Use cached results from kd-tree to avoid expensive calculations
    if (!m_nearbyClusters.count(slidingFitResult1.GetCluster()) || !m_nearbyClusters.count(slidingFitResult2.GetCluster()) ||
        !m_nearbyClusters.at(slidingFitResult1.GetCluster()).count(slidingFitResult2.GetCluster()) ||
        !m_nearbyClusters.at(slidingFitResult2.GetCluster()).count(slidingFitResult1.GetCluster()))
    {
        return STATUS_CODE_NOT_FOUND;
    }

    // Identify crossed-track topology and find candidate intersection positions
    const CartesianVector &minPosition1(slidingFitResult1.GetGlobalMinLayerPosition());
    const CartesianVector &maxPosition1(slidingFitResult1.GetGlobalMaxLayerPosition());

    const CartesianVector &minPosition2(slidingFitResult2.GetGlobalMinLayerPosition());
    const CartesianVector &maxPosition2(slidingFitResult2.GetGlobalMaxLayerPosition());

    if (LArClusterHelper::GetClosestDistance(minPosition1, slidingFitResult2.GetCluster()) < 2.f * m_maxClusterSeparation ||
        LArClusterHelper::GetClosestDistance(maxPosition1, slidingFitResult2.GetCluster()) < 2.f * m_maxClusterSeparation ||
        LArClusterHelper::GetClosestDistance(minPosition2, slidingFitResult1.GetCluster()) < 2.f * m_maxClusterSeparation ||
        LArClusterHelper::GetClosestDistance(maxPosition2, slidingFitResult1.GetCluster()) < 2.f * m_maxClusterSeparation)
    {
        return STATUS_CODE_NOT_FOUND;
    }

    if (LArClusterHelper::GetClosestDistance(slidingFitResult1.GetCluster(), slidingFitResult2.GetCluster()) > m_maxClusterSeparation)
        return STATUS_CODE_NOT_FOUND;

    CartesianPointVector candidateVector;
    this->FindCandidateSplitPositions(slidingFitResult1.GetCluster(), slidingFitResult2.GetCluster(), candidateVector);

    if (candidateVector.empty())
        return STATUS_CODE_NOT_FOUND;

    // Loop over candidate positions and find best split position
    bool foundSplit(false);
    float closestSeparationSquared(std::numeric_limits<float>::max());

    const float halfWindowLength1(slidingFitResult1.GetLayerFitHalfWindowLength());
    const float halfWindowLength2(slidingFitResult2.GetLayerFitHalfWindowLength());

    for (CartesianPointVector::const_iterator iter = candidateVector.begin(), iterEnd = candidateVector.end(); iter != iterEnd; ++iter)
    {
        const CartesianVector &candidatePosition(*iter);

        // Projections onto first cluster
        float rL1(0.f), rT1(0.f);
        CartesianVector R1(0.f, 0.f, 0.f);
        CartesianVector F1(0.f, 0.f, 0.f);
        CartesianVector B1(0.f, 0.f, 0.f);

        if (STATUS_CODE_SUCCESS != slidingFitResult1.GetGlobalFitProjection(candidatePosition, R1))
            continue;

        slidingFitResult1.GetLocalPosition(R1, rL1, rT1);
        if ((STATUS_CODE_SUCCESS != slidingFitResult1.GetGlobalFitPosition(rL1 + halfWindowLength1, F1)) ||
            (STATUS_CODE_SUCCESS != slidingFitResult1.GetGlobalFitPosition(rL1 - halfWindowLength1, B1)))
        {
            continue;
        }

        // Projections onto second cluster
        float rL2(0.f), rT2(0.f);
        CartesianVector R2(0.f, 0.f, 0.f);
        CartesianVector F2(0.f, 0.f, 0.f);
        CartesianVector B2(0.f, 0.f, 0.f);

        if (STATUS_CODE_SUCCESS != slidingFitResult2.GetGlobalFitProjection(candidatePosition, R2))
            continue;

        slidingFitResult2.GetLocalPosition(R2, rL2, rT2);
        if ((STATUS_CODE_SUCCESS != slidingFitResult2.GetGlobalFitPosition(rL2 + halfWindowLength2, F2)) ||
            (STATUS_CODE_SUCCESS != slidingFitResult2.GetGlobalFitPosition(rL2 - halfWindowLength2, B2)))
        {
            continue;
        }

        // Calculate average position
        const CartesianVector C0((R1 + R2) * 0.5);

        // Calculate intersected position:
        // ==============================
        // First cluster gives set of points: B1->R1->F1
        // Second cluster gives set of points: B2->R2->F2
        //
        // Try swapping B1 with B2 to see if this gives intersecting straight lines:
        //
        //   F1   F2     a2   b1
        //    |   |       |   |
        //     |  |        |  |
        //     R1 R2       R1 R2
        //      | |         |  |
        //      |  |        |   |
        //     B1   B2     a1    b2

        // First straight line is a1->R1->b1
        // Second straight line is a2->R2->b2

        const CartesianVector a1(B1);
        const CartesianVector a2(F1);

        for (unsigned int iForward = 0; iForward < 2; ++iForward)
        {
            const CartesianVector b1((0 == iForward) ? F2 : B2);
            const CartesianVector b2((0 == iForward) ? B2 : F2);

            const CartesianVector s1((b1 - R2).GetUnitVector());
            const CartesianVector t1((R1 - a1).GetUnitVector());
            const CartesianVector s2((b2 - R2).GetUnitVector());
            const CartesianVector t2((R1 - a2).GetUnitVector());

            if (s1.GetDotProduct(t1) < std::max(m_minCosRelativeAngle, -s1.GetDotProduct(s2)) ||
                s2.GetDotProduct(t2) < std::max(m_minCosRelativeAngle, -t1.GetDotProduct(t2)))
                continue;

            const CartesianVector p1((b1 - a1).GetUnitVector());
            const CartesianVector p2((b2 - a2).GetUnitVector());

            float mu1(0.f), mu2(0.f);
            CartesianVector C1(0.f, 0.f, 0.f);

            try
            {
                LArPointingClusterHelper::GetIntersection(a1, p1, a2, p2, C1, mu1, mu2);
            }
            catch (const StatusCodeException &)
            {
                continue;
            }

            if (mu1 < 0.f || mu2 < 0.f || mu1 > (b1 - a1).GetMagnitude() || mu2 > (b2 - a2).GetMagnitude())
                continue;

            const float thisSeparationSquared((C0 - C1).GetMagnitudeSquared());

            if (thisSeparationSquared < closestSeparationSquared)
            {
                closestSeparationSquared = thisSeparationSquared;
                splitPosition = (C0 + C1) * 0.5;
                firstDirection = t2 * -1.f;
                secondDirection = t1;
                foundSplit = true;
            }
        }
    }

    if (!foundSplit)
        return STATUS_CODE_NOT_FOUND;

    return STATUS_CODE_SUCCESS;
}

//------------------------------------------------------------------------------------------------------------------------------------------

void CrossedTrackSplittingAlgorithm::FindCandidateSplitPositions(
    const Cluster *const pCluster1, const Cluster *const pCluster2, CartesianPointVector &candidateVector) const
{
    // ATTN The following is double-double counting
    CaloHitList caloHitList1, caloHitList2;
    pCluster1->GetOrderedCaloHitList().FillCaloHitList(caloHitList1);
    pCluster2->GetOrderedCaloHitList().FillCaloHitList(caloHitList2);

    CaloHitVector caloHitVector1(caloHitList1.begin(), caloHitList1.end()), caloHitVector2(caloHitList2.begin(), caloHitList2.end());
    std::sort(caloHitVector1.begin(), caloHitVector1.end(), LArClusterHelper::SortHitsByPosition);
    std::sort(caloHitVector2.begin(), caloHitVector2.end(), LArClusterHelper::SortHitsByPosition);

    for (const CaloHit *const pCaloHit : caloHitVector1)
    {
        const CartesianVector position1(pCaloHit->GetPositionVector());
        const CartesianVector position2(LArClusterHelper::GetClosestPosition(position1, pCluster2));

        if ((position1 - position2).GetMagnitudeSquared() < m_maxClusterSeparationSquared)
            candidateVector.push_back((position1 + position2) * 0.5);
    }

    for (const CaloHit *const pCaloHit : caloHitVector2)
    {
        const CartesianVector position2(pCaloHit->GetPositionVector());
        const CartesianVector position1(LArClusterHelper::GetClosestPosition(position2, pCluster1));

        if ((position2 - position1).GetMagnitudeSquared() < m_maxClusterSeparationSquared)
            candidateVector.push_back((position2 + position1) * 0.5);
    }
}

//------------------------------------------------------------------------------------------------------------------------------------------

StatusCode CrossedTrackSplittingAlgorithm::ReadSettings(const TiXmlHandle xmlHandle)
{
    PANDORA_RETURN_RESULT_IF_AND_IF(
        STATUS_CODE_SUCCESS, STATUS_CODE_NOT_FOUND, !=, XmlHelper::ReadValue(xmlHandle, "MaxClusterSeparation", m_maxClusterSeparation));
    m_maxClusterSeparationSquared = m_maxClusterSeparation * m_maxClusterSeparation;

    PANDORA_RETURN_RESULT_IF_AND_IF(
        STATUS_CODE_SUCCESS, STATUS_CODE_NOT_FOUND, !=, XmlHelper::ReadValue(xmlHandle, "MinCosRelativeAngle", m_minCosRelativeAngle));

    PANDORA_RETURN_RESULT_IF_AND_IF(STATUS_CODE_SUCCESS, STATUS_CODE_NOT_FOUND, !=, XmlHelper::ReadValue(xmlHandle, "SearchRegion1D", m_searchRegion1D));

    return TwoDSlidingFitSplittingAndSwitchingAlgorithm::ReadSettings(xmlHandle);
}

} // namespace lar_content