DeviceDetectorDescriptionSvc.cxx

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/*
  Copyright (C) 2002-2026 CERN for the benefit of the ATLAS collaboration
*/
#include "DeviceDetectorDescriptionSvc.h"
#include "StoreGate/StoreGateSvc.h"
#include "HGTD_ReadoutGeometry/HGTD_DetectorElement.h"
 
#include <cmath>
#include <optional>
 
namespace ActsTrk {
 
std::vector<traccc::scalar> makeEquidistantEdges(float halfWidth, int nBins) {
    std::vector<traccc::scalar> edges;
    edges.reserve(nBins + 1);
    const float min = -halfWidth;
    const float pitch = (2.f * halfWidth) / static_cast<float>(nBins);
    for (int i = 0; i <= nBins; ++i) {
        edges.push_back(static_cast<traccc::scalar>(min + static_cast<float>(i) * pitch));
    }
    return edges;
}
 
StatusCode DeviceDetectorDescriptionSvc::initialize()
{
    ATH_MSG_DEBUG("Initializing  device detector description provider service ");
 
    ATH_CHECK(m_MRs.retrieve());
    ATH_CHECK(m_copy.retrieve());
    ATH_CHECK(m_detStore.retrieve());
 
    ATH_CHECK(m_detStore->retrieve(m_pixelID, m_pixelIdHelperName) );
    ATH_CHECK(m_detStore->retrieve(m_stripID, m_stripIdHelperName));
    ATH_CHECK(m_detStore->retrieve(m_pixelManager, "ITkPixel"));
    ATH_CHECK(m_detStore->retrieve(m_stripManager, "ITkStrip"));
 
    std::map<Acts::GeometryIdentifier, Identifier> actsToAthena;
    std::unordered_map<uint64_t, Identifier> detrayToAthenaMap;
    std::unordered_map<Identifier, uint64_t> athenaToDetrayMap;
 
    int nPix = 0, nStrip = 0, nEC = 0, nBar = 0;
    std::vector<Acts::GeometryIdentifier> actsHGTD;
    if (!m_trackingGeometrySvc.empty()) {
 
        // ---- 1. Get ACTS Tracking Geometry, populate Athena<->ACTS maps and fill module design (segmentation) information ----
        // all of these are static upon construction through the run
 
        ATH_CHECK(m_trackingGeometrySvc.retrieve());
        m_trackingGeometry = m_trackingGeometrySvc->trackingGeometry();
 
        m_trackingGeometry->visitSurfaces([&](const Acts::Surface *surface) {
            if (!surface) return;
            const auto *actsElement = getActsDetectorElement(surface);
            if (!actsElement){
                ATH_MSG_DEBUG("Could not find matching Acts detector element for surface with geometryId " << surface->geometryId());
                return;
            }
            
            const ActsTrk::DetectorType detType = actsElement->detectorType();
            if (detType == ActsTrk::DetectorType::Hgtd) {
                // skip HGTD surfaces for now
                // currently no time info is being used in traccc
                ATH_MSG_VERBOSE("Found HGTD surface with geometryId " << surface->geometryId());
                actsHGTD.push_back(surface->geometryId());
                return;
            }
            if (detType != ActsTrk::DetectorType::Pixel && detType != ActsTrk::DetectorType::Sct) {
                ATH_MSG_DEBUG("Found non-pixel, non-strip detector element with geometryId " << surface->geometryId());
                return;
            }
            const auto *detElem = dynamic_cast<const InDetDD::SiDetectorElement*>(actsElement->upstreamDetectorElement());
            if (!detElem) {
                ATH_MSG_DEBUG("Could not find matching Athena silicon detector element for surface with geometryId " << surface->geometryId());
                return;
            }
 
            Identifier athenaID;
            moduleInfo thismod;
            // NOTE: lorentz_shift_x/y intentionally left at their default
            // (0.f) — they're not used for design-shape grouping and are
            // computed per-IOV by DeviceDetectorDescriptionCondAlg, so no
            // Lorentz-tool call happens here.
 
            thismod.isAnnulus = false;
            thismod.pixel = false;
            thismod.equidistant_binning = true;
 
            switch (detType) {
                case ActsTrk::DetectorType::Pixel: {
                    ++nPix;
                    athenaID = detElem->identify();
                    const auto* p_design = static_cast<const InDetDD::PixelModuleDesign*>(&detElem->design());
                    
                    thismod.pixel = true;
                    thismod.side = 2; // for pixel
 
                    std::vector<traccc::scalar> row_centres;
                    std::vector<traccc::scalar> column_centres;
 
                    // pixels with cross design 
                    // the middle four rows and columns are double pitch
                    if ((m_pixelID->barrel_ec(athenaID) == 0 && m_pixelID->layer_disk(athenaID) > 0) ||
                        (m_pixelID->barrel_ec(athenaID) != 0 && m_pixelID->layer_disk(athenaID) > 1)) {
 
                        thismod.equidistant_binning = false;
 
                        for(int row = 0; row < p_design->rows(); row++){
 
                            std::array<InDetDD::PixelDiodeTree::CellIndexType, 2>
                                diode_idx = InDetDD::PixelDiodeTree::makeCellIndex(
                                    row, 0);
                            InDetDD::PixelDiodeTree::DiodeProxyWithPosition si_param(
                                p_design->diodeProxyFromIdxCachePosition(diode_idx));
 
                            (row_centres).push_back(si_param.position()[0]-0.5*si_param.width()[0]);
                            if(row == p_design->rows()-1){
                                (row_centres).push_back(si_param.position()[0]+0.5*si_param.width()[0]);
                            }
 
                            float leading_edge  = si_param.position()[0] - 0.5f*si_param.width()[0];
                            float trailing_edge = si_param.position()[0] + 0.5f*si_param.width()[0];
                            float midpoint = (leading_edge + trailing_edge) / 2.f;
                            if(std::abs(midpoint - si_param.position()[0]) > 1e-6f){
                                ATH_MSG_ERROR("Row " << row << " edge midpoint " << midpoint
                                            << " != geometry centre " << si_param.position()[0]
                                            << " (diff=" << midpoint - si_param.position()[0] << ")");
                            }
 
                        }
                        for(int col = 0; col < p_design->columns(); col++){
 
                            std::array<InDetDD::PixelDiodeTree::CellIndexType, 2>
                                diode_idx = InDetDD::PixelDiodeTree::makeCellIndex(
                                    0, col);
                            InDetDD::PixelDiodeTree::DiodeProxyWithPosition si_param(
                                p_design->diodeProxyFromIdxCachePosition(diode_idx));
 
                            (column_centres).push_back(si_param.position()[1]-0.5*si_param.width()[1]);
                            if(col == p_design->columns()-1){
                                (column_centres).push_back(si_param.position()[1]+0.5*si_param.width()[1]);
                            }
 
                            float leading_edge  = si_param.position()[1] - 0.5f*si_param.width()[1];
                            float trailing_edge = si_param.position()[1] + 0.5f*si_param.width()[1];
                            float midpoint = (leading_edge + trailing_edge) / 2.f;
                            if(std::abs(midpoint - si_param.position()[1]) > 1e-6f){
                                ATH_MSG_ERROR("Column " << col << " edge midpoint " << midpoint
                                            << " != geometry centre " << si_param.position()[1]
                                            << " (diff=" << midpoint - si_param.position()[1] << ")");
                            }
 
                        }
 
                    }
 
                    thismod.row_centres = row_centres;
                    thismod.column_centres = column_centres;
 
                    thismod.module_width = p_design->width();
                    thismod.module_length = p_design->length();
                    thismod.rows = p_design->rows();
                    thismod.columns = p_design->columns();
                    break;
                }
                case ActsTrk::DetectorType::Sct: {
                    ++nStrip;
                    const Identifier moduleID = m_stripID->module_id(detElem->identify());
                    const IdentifierHash moduleHash = m_stripID->wafer_hash(moduleID);
                    const int side = m_stripID->side(detElem->identify());
                    athenaID = m_stripID->wafer_id(moduleHash + side);
 
                    thismod.pixel = false;
                    thismod.side = side;
                    thismod.columns = 1; // for strip
 
                    if (m_stripID->barrel_ec(athenaID) == 0) {
                        ++nBar;
                        const auto* s_design = static_cast<const InDetDD::SCT_BarrelModuleSideDesign*>(&detElem->design());
                        
                        thismod.module_width = s_design->width();
                        thismod.module_length = s_design->length();
                        thismod.rows = s_design->cells();
                    } else {
                        ++nEC;
                        const auto* annulus_design = static_cast<const InDetDD::StripStereoAnnulusDesign*>(&detElem->design());
                        const InDetDD::SiCellId annulus_cell = detElem->cellIdFromIdentifier(athenaID);
                        const double pitch_row = annulus_design->phiPitchPhi(annulus_cell);
                        const int nDiodes = annulus_design->diodesInRow(0.);
                        const double max_phi = nDiodes * pitch_row;
                        thismod.module_width = -max_phi;
                        // this could be the halfway point in radius, number is arbitrary
                        // const double radius = annulus_design->centreR();
                        thismod.module_length = 0.2; //radius;
                        thismod.rows = nDiodes;
                        thismod.isAnnulus = true;
                    }
                    break;
                }
                default:
                    // unreachable, see filter above
                    return;
            }
            
            m_atlasModuleInfo[athenaID] = thismod;
            const auto geo_id = surface->geometryId();
            actsToAthena[geo_id] = athenaID;
            
        });
 
        ATH_MSG_DEBUG(nPix << " Atlas Pixel modules found.");
        ATH_MSG_DEBUG(nStrip << " Atlas Strip modules found, " << nBar << " in barrel and " << nEC << " in the endcap");
        ATH_MSG_DEBUG("Wrote segmentation info for " << m_atlasModuleInfo.size() << " modules");
 
        // ---- 2. Get Detray Tracking Geometry and populate Detray<->ACTS map ----
        ATH_MSG_INFO("Loading detray detector");
        
        int found_detray = 0; 
        int missing_detray = 0; 
        int missing_detray_passives = 0;
 
        auto hostDetector = m_trackingGeometrySvc->detrayGeometry();
        const auto& itkDetector = hostDetector->as<traccc::itk_detector>();
        for (const auto& surface : itkDetector.surfaces()) {
            const auto geo_id = surface.source;
            const Acts::GeometryIdentifier acts_geom_id{geo_id};
            auto sf = detray::tracking_surface{itkDetector, surface};
            const auto detray_id = sf.identifier().value();
 
            if (auto pIdPair = actsToAthena.find(acts_geom_id); pIdPair != actsToAthena.end()) {
                auto athena_id = pIdPair->second;
                detrayToAthenaMap[detray_id] = athena_id;
                athenaToDetrayMap[athena_id] = detray_id;
                found_detray++;
            } else {
                if (std::find(actsHGTD.begin(), actsHGTD.end(), acts_geom_id) != actsHGTD.end()) {
                    ATH_MSG_VERBOSE("ACTS surface with key " << acts_geom_id << " is HGTD, detray id: " << detray_id);
                    continue;
                }
                ATH_MSG_VERBOSE("ACTS surface with key " << acts_geom_id << " was not translated to detray geometry.");
                missing_detray++;
                if (surface.is_sensitive()) continue;
                ATH_MSG_VERBOSE("found this passive surface in detray: " << acts_geom_id);
                missing_detray_passives++;
            }
        }
 
        ATH_MSG_DEBUG("Traccc detector has " << found_detray << " surfaces matching ACTS and " << missing_detray << " additional surfaces, out of which " << missing_detray_passives << " are not sensitive.");
 
        // ---- 3. Deduplicate the designs ----
        // there are only a handful of unique module designs, only store unique values
        // and populate the detray<->acts<->athena geometry ID relationship map
        std::map<designKey, unsigned int> designLookup;
        unsigned int nextDesignId = 0;
 
        const std::size_t nSurfaces = itkDetector.surfaces().size();
        m_staticCondEntries.resize(nSurfaces);
 
        auto idMapping = std::make_unique<ActsTrk::GeometryIdMapping>();
        idMapping->reserve(nSurfaces);
 
        for (std::size_t condIndex = 0; condIndex < nSurfaces; ++condIndex) {
            const auto& surface = itkDetector.surfaces()[condIndex];
             if (!surface.is_sensitive()) {
                ATH_MSG_VERBOSE("Skipping passive surface with geometryId " << surface.source);
                continue;
            }
            const auto geo_id = surface.source;
            const Acts::GeometryIdentifier acts_geom_id{geo_id};
            auto sf = detray::tracking_surface{itkDetector, surface};
            const auto detray_id = sf.identifier().value();
 
            StaticCondEntry entry;
            entry.detrayGeometryId = detray::geometry::identifier{detray_id};
            entry.actsGeometryId = acts_geom_id.value();
 
            auto detrayIt = detrayToAthenaMap.find(detray_id);
            std::optional<Identifier> athenaId;
            if (detrayIt != detrayToAthenaMap.end()) {
                athenaId = detrayIt->second;
                auto modIt = m_atlasModuleInfo.find(*athenaId);
                if (modIt != m_atlasModuleInfo.end()) {
                    const moduleInfo& thismod = modIt->second;
 
                    const int nBinsX = thismod.rows;
                    const int nBinsY = thismod.pixel ? thismod.columns : 1;
 
                    auto edgesX = makeEquidistantEdges(0.5f * thismod.module_width, nBinsX);
                    auto edgesY = makeEquidistantEdges(0.5f * thismod.module_length, nBinsY);
 
                    if(!thismod.equidistant_binning){
                        edgesX = thismod.row_centres;
                        edgesY = thismod.column_centres;
                    }
                    
                    designKey key{thismod.pixel, thismod.isAnnulus, edgesX, edgesY,
                                std::abs(thismod.module_width), thismod.module_length};
 
                    const auto [it, inserted] = designLookup.try_emplace(key, nextDesignId);
                    entry.designId = it->second;
                    if (inserted) ++nextDesignId;
 
                    entry.athenaId = *athenaId;
                    entry.hasAthenaModule = true;
                    entry.isPixel = thismod.pixel;
                }
            }else{
                if (std::find(actsHGTD.begin(), actsHGTD.end(), acts_geom_id) != actsHGTD.end()) {
                    ATH_MSG_VERBOSE("ACTS surface with key " << acts_geom_id << " is HGTD, detray id: " << detray_id);
                    continue;
                }
                ATH_MSG_ERROR("Could not find matching Athena module for detray surface with geometryId " << detray_id);
                return StatusCode::FAILURE;
            }
 
            idMapping->addEntry(detray_id, acts_geom_id.value(), athenaId);
            // condIndex is the row of this surface in the detector conditions description
            idMapping->addDetDescIndex(detray_id, static_cast<unsigned int>(condIndex));
            m_staticCondEntries[condIndex] = entry;
        }
 
 
        // ---- 4. Write detector design object ----
        auto hostDesign = std::make_unique<traccc::detector_design_description::host>(*m_MRs->hostMR());
        hostDesign->resize(designLookup.size());
        for (const auto& [key, id] : designLookup) {
            hostDesign->design_id()[id] = static_cast<int>(id);
 
            hostDesign->dimensions()[id] = key.pixel ? 2 : 1;
        
            if(!key.isAnnulus){
                hostDesign->bin_edges_x()[id].assign(key.edgesX.begin(), key.edgesX.end());
                hostDesign->bin_edges_y()[id].assign(key.edgesY.begin(), key.edgesY.end());
                hostDesign->subspace()[id] = std::array<detray::dindex_type<traccc::default_algebra>, 2u>{0u, 1u};
            }else{
                hostDesign->bin_edges_y()[id].assign(key.edgesX.begin(), key.edgesX.end());
                hostDesign->bin_edges_x()[id].assign(key.edgesY.begin(), key.edgesY.end());
                hostDesign->subspace()[id] = std::array<detray::dindex_type<traccc::default_algebra>, 2u>{1u, 0u};
            }
            
        }
 
        std::vector<unsigned int> designSizes(hostDesign->size());
        for (std::size_t i = 0; i < hostDesign->size(); ++i) {
            auto thisDesign = hostDesign->at(i);
            designSizes[i] = std::max(
                static_cast<unsigned int>(thisDesign.bin_edges_x().size()),
                static_cast<unsigned int>(thisDesign.bin_edges_y().size()));
        }
 
        auto initCopy = m_copy->copy(EventContext{});
        auto deviceDesign = std::make_unique<traccc::detector_design_description::buffer>(
            designSizes, m_MRs->mainMR(), m_MRs->hostMR(),
            vecmem::data::buffer_type::resizable);
        (*initCopy).setup(*deviceDesign)->wait();
        (*initCopy)(vecmem::get_data(*hostDesign), *deviceDesign)->wait();
 
        constexpr bool allowMods = false;
        ATH_CHECK(m_detStore->record(std::move(deviceDesign), m_deviceDesignObjectName.value(), allowMods));
        ATH_CHECK(m_detStore->record(std::move(hostDesign), m_hostDesignObjectName.value(), allowMods));
        ATH_CHECK(m_detStore->record(std::move(idMapping), m_geoIdMappingObjectName.value(), allowMods));
 
        auto deviceDetector = std::make_unique<traccc::detector_buffer>();
        deviceDetector->set<traccc::itk_detector>(
            detray::get_buffer(itkDetector, m_MRs->mainMR(), const_cast<vecmem::copy&>(*initCopy)));
        ATH_CHECK(m_detStore->record(std::move(deviceDetector), m_deviceDetectorName.value(), allowMods));
        
        ATH_MSG_DEBUG("Recorded host and device detector design description: " << m_hostDesignObjectName.value() << ", " << m_deviceDesignObjectName.value());
 
    } else {
        ATH_MSG_FATAL("Tracking Geometry empty!!");
        return StatusCode::FAILURE;
    }
 
 
    return StatusCode::SUCCESS;
}
 
} // namespace ActsTrk