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feat: Geant4SurfaceProvider optimization (#3025)
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Introducing minor changes to the `Geant4SurfaceProvider` targeting optimization and utility for Telescope-style use cases. 

The first change is the removal of the Gdml parsing from the construction in favor of supplying a pointer to the world volume. The Internal Structure Builder is called (potentially) multiple times in the builder pipeline, so, before the changes, the description was also parsed multiple times and several Worlds were kept in the memory. 

The second change has to do with the conventional z-orientation of the Telescope geometries. There's a need to rotate the  geometries away from the z-axis in the current implementation of the track parametrization, so a simple way of applying a global transformation at the construction stage is introduced. In our experience, the cleanest way to do it is on the Geant4 volumes conversion stage, thus the additional `G4Transform` is included into the `Config`.
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@ssdetlab
ssdetlab authored Mar 20, 2024
1 parent e033607 commit c3eea1c
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Showing 2 changed files with 42 additions and 33 deletions.
35 changes: 15 additions & 20 deletions Plugins/Geant4/include/Acts/Plugins/Geant4/Geant4SurfaceProvider.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -43,8 +43,8 @@ class Geant4SurfaceProvider : public Acts::Experimental::ISurfacesProvider {
public:
/// Nested configuration struct
struct Config {
/// The path of the gdml file
std::string gdmlPath = "";
/// Pointer to the g4World volume
const G4VPhysicalVolume* g4World = nullptr;

/// Convert the length scale
ActsScalar scaleConversion = 1.;
Expand All @@ -55,6 +55,10 @@ class Geant4SurfaceProvider : public Acts::Experimental::ISurfacesProvider {
/// Converted material thickness (< 0 indicates keeping original thickness)
ActsScalar convertedMaterialThickness = -1;

/// Transformation to apply to the
/// G4World volume
G4Transform3D worldTransform = G4Transform3D();

/// A selector for passive surfaces
std::shared_ptr<IGeant4PhysicalVolumeSelector> surfacePreselector =
std::make_shared<Acts::Geant4PhysicalVolumeSelectors::AllSelector>();
Expand Down Expand Up @@ -85,13 +89,11 @@ class Geant4SurfaceProvider : public Acts::Experimental::ISurfacesProvider {
/// Constructor
/// @param config The configuration struct
/// @param options The optional configuration for KDTree
/// @param validateGDMLschema Whether to validate the gdml schema
Geant4SurfaceProvider(const Config& config,
const kdtOptions& options = kdtOptions(),
bool validateGDMLschema = true) {
if (config.gdmlPath.empty()) {
const kdtOptions& options = kdtOptions()) {
if (config.g4World == nullptr) {
throw std::invalid_argument(
"Geant4SurfaceProvider: no gdml file provided");
"Geant4SurfaceProvider: No World volume provided");
}
if (config.surfacePreselector == nullptr) {
throw std::invalid_argument(
Expand All @@ -100,16 +102,8 @@ class Geant4SurfaceProvider : public Acts::Experimental::ISurfacesProvider {

m_cfg = config;
m_kdtOptions = options;

/// Read the gdml file and get the world volume
G4GDMLParser parser;
parser.Read(m_cfg.gdmlPath, validateGDMLschema);
m_g4World = parser.GetWorldVolume();

if (m_g4World == nullptr) {
throw std::invalid_argument(
"Geant4SurfaceProvider: No g4World initialized");
}
m_g4World = m_cfg.g4World;
m_g4ToWorld = m_cfg.worldTransform;
};

/// Destructor
Expand All @@ -131,11 +125,10 @@ class Geant4SurfaceProvider : public Acts::Experimental::ISurfacesProvider {

/// Generate the surface cache
Acts::Geant4DetectorSurfaceFactory::Cache g4SurfaceCache;
G4Transform3D g4ToWorld;

/// Find and store surfaces in the cache object
Acts::Geant4DetectorSurfaceFactory{}.construct(
g4SurfaceCache, g4ToWorld, *m_g4World, g4SurfaceOptions);
g4SurfaceCache, m_g4ToWorld, *m_g4World, g4SurfaceOptions);

auto surfaces = g4SurfaceCache.passiveSurfaces;

Expand All @@ -157,7 +150,9 @@ class Geant4SurfaceProvider : public Acts::Experimental::ISurfacesProvider {

kdtOptions m_kdtOptions;

G4VPhysicalVolume* m_g4World = nullptr;
const G4VPhysicalVolume* m_g4World;

G4Transform3D m_g4ToWorld;
};

} // namespace Experimental
Expand Down
40 changes: 27 additions & 13 deletions Tests/UnitTests/Plugins/Geant4/Geant4SurfaceProviderTests.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -113,17 +113,21 @@ auto gctx = Acts::GeometryContext();
auto [physWorld, names] = ConstructGeant4World();

BOOST_AUTO_TEST_CASE(Geant4SurfaceProviderNames) {
/// Read the gdml file and get the world volume
G4GDMLParser parser;
parser.Read(gdmlPath.string(), false);
auto world = parser.GetWorldVolume();

// Default template parameters are fine
// when using names as identifiers
auto spFullCfg = Acts::Experimental::Geant4SurfaceProvider<>::Config();
spFullCfg.gdmlPath = gdmlPath.string();
spFullCfg.g4World = world;
spFullCfg.surfacePreselector =
std::make_shared<Acts::Geant4PhysicalVolumeSelectors::NameSelector>(names,
true);

auto spFull = std::make_shared<Acts::Experimental::Geant4SurfaceProvider<>>(
spFullCfg, Acts::Experimental::Geant4SurfaceProvider<>::kdtOptions(),
false);
spFullCfg, Acts::Experimental::Geant4SurfaceProvider<>::kdtOptions());

auto lbFullCfg = Acts::Experimental::LayerStructureBuilder::Config();
lbFullCfg.surfacesProvider = spFull;
Expand Down Expand Up @@ -157,15 +161,15 @@ BOOST_AUTO_TEST_CASE(Geant4SurfaceProviderNames) {
names.begin() + names.size() / 2);

auto spLeftArmCfg = Acts::Experimental::Geant4SurfaceProvider<>::Config();
spLeftArmCfg.gdmlPath = gdmlPath.string();
spLeftArmCfg.g4World = world;
spLeftArmCfg.surfacePreselector =
std::make_shared<Acts::Geant4PhysicalVolumeSelectors::NameSelector>(
leftArmNames, true);

auto spLeftArm =
std::make_shared<Acts::Experimental::Geant4SurfaceProvider<>>(
spLeftArmCfg,
Acts::Experimental::Geant4SurfaceProvider<>::kdtOptions(), false);
Acts::Experimental::Geant4SurfaceProvider<>::kdtOptions());

auto lbCfg = Acts::Experimental::LayerStructureBuilder::Config();
lbCfg.surfacesProvider = spLeftArm;
Expand All @@ -190,17 +194,22 @@ BOOST_AUTO_TEST_CASE(Geant4SurfaceProviderNames) {
}

BOOST_AUTO_TEST_CASE(Geant4SurfaceProviderRanges) {
/// Read the gdml file and get the world volume
G4GDMLParser parser;
parser.Read(gdmlPath.string(), false);
auto world = parser.GetWorldVolume();

// 1D selection -- select only the second row
auto sp1DCfg = Acts::Experimental::Geant4SurfaceProvider<1>::Config();
sp1DCfg.gdmlPath = gdmlPath.string();
sp1DCfg.g4World = world;

auto kdt1DOpt = Acts::Experimental::Geant4SurfaceProvider<1>::kdtOptions();
kdt1DOpt.range = Acts::RangeXD<1, Acts::ActsScalar>();
kdt1DOpt.range[0].set(8, 12);
kdt1DOpt.binningValues = {Acts::BinningValue::binZ};

auto sp1D = std::make_shared<Acts::Experimental::Geant4SurfaceProvider<1>>(
sp1DCfg, kdt1DOpt, false);
sp1DCfg, kdt1DOpt);

auto lb1DCfg = Acts::Experimental::LayerStructureBuilder::Config();
lb1DCfg.surfacesProvider = sp1D;
Expand All @@ -226,7 +235,7 @@ BOOST_AUTO_TEST_CASE(Geant4SurfaceProviderRanges) {
// 2D selection -- select only the second row
// of the left arm
auto sp2DCfg = Acts::Experimental::Geant4SurfaceProvider<2>::Config();
sp2DCfg.gdmlPath = gdmlPath.string();
sp2DCfg.g4World = world;

auto kdt2DOpt = Acts::Experimental::Geant4SurfaceProvider<2>::kdtOptions();
kdt2DOpt.range = Acts::RangeXD<2, Acts::ActsScalar>();
Expand All @@ -235,7 +244,7 @@ BOOST_AUTO_TEST_CASE(Geant4SurfaceProviderRanges) {
kdt2DOpt.binningValues = {Acts::BinningValue::binZ};

auto sp2D = std::make_shared<Acts::Experimental::Geant4SurfaceProvider<2>>(
sp2DCfg, kdt2DOpt, false);
sp2DCfg, kdt2DOpt);

auto lb2DCfg = Acts::Experimental::LayerStructureBuilder::Config();
lb2DCfg.surfacesProvider = sp2D;
Expand All @@ -257,7 +266,7 @@ BOOST_AUTO_TEST_CASE(Geant4SurfaceProviderRanges) {
// Preselect the left arm based on the position
// and select only the second row
auto sp2DPosCfg = Acts::Experimental::Geant4SurfaceProvider<1>::Config();
sp2DPosCfg.gdmlPath = gdmlPath.string();
sp2DPosCfg.g4World = world;
std::map<unsigned int, std::tuple<double, double>> ranges;

std::array<unsigned int, 3> g4Axes{0};
Expand All @@ -274,7 +283,7 @@ BOOST_AUTO_TEST_CASE(Geant4SurfaceProviderRanges) {
ranges);

auto sp2DPos = std::make_shared<Acts::Experimental::Geant4SurfaceProvider<1>>(
sp2DPosCfg, kdt1DOpt, false);
sp2DPosCfg, kdt1DOpt);

auto lb2DPosCfg = Acts::Experimental::LayerStructureBuilder::Config();
lb2DPosCfg.surfacesProvider = sp2DPos;
Expand Down Expand Up @@ -345,10 +354,15 @@ BOOST_AUTO_TEST_CASE(Geant4RectangleFromGDML) {

bgdml.close();

/// Read the gdml file and get the world volume
G4GDMLParser parser;
parser.Read("Plane.gdml", false);
auto world = parser.GetWorldVolume();

// 1D selection -- select only the second row
auto planeFromGDMLCfg =
Acts::Experimental::Geant4SurfaceProvider<1>::Config();
planeFromGDMLCfg.gdmlPath = "Plane.gdml";
planeFromGDMLCfg.g4World = world;
planeFromGDMLCfg.surfacePreselector =
std::make_shared<Acts::Geant4PhysicalVolumeSelectors::NameSelector>(
std::vector<std::string>{"b_pv"}, true);
Expand All @@ -362,7 +376,7 @@ BOOST_AUTO_TEST_CASE(Geant4RectangleFromGDML) {

auto planeProvider =
std::make_shared<Acts::Experimental::Geant4SurfaceProvider<1>>(
planeFromGDMLCfg, kdt1DOpt, false);
planeFromGDMLCfg, kdt1DOpt);

auto planes = planeProvider->surfaces(tContext);
BOOST_CHECK_EQUAL(planes.size(), 1u);
Expand Down

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