G4DAEChroma Implementation Details

G4DAEChroma Dependencies

Geant4

Simulation Toolkit

ZMQ

ZeroMQ message queue transport

cJSON

JSON string serialization/deserialization

numpy.hpp

NumPy array serialization/deserialization

RapSQLite

Interface to SQLite3 database, for control/monitoring.

CNPY

NumPy array serialization/deserialization, (to be eliminated by migration to numpy.hpp)

Former dependency on ROOT for TObject serialization has been eliminated.

High Level API

G4DAEChroma : G4DAEManager

high level API for collection of Geant4 data and external processing and integration back into propagation

G4DAEManager

task control and timing

Collectable/Transportable Object Definitions

Template type providing type specifics, describing shape and content of arrays and template envvars that standardize location of persisted lists.

G4DAEPhoton.hh
G4DAECerenkovPhoton.hh
G4DAECerenkovStep.hh
G4DAEScintillationStep.hh
G4DAEScintillationPhoton.hh
G4DAEPmtHit.hh
G4DAEProp.hh

Collectable/Transportable Lists

Template specializations of G4DAEList eg:

typedef G4DAEList<G4DAEPhoton> G4DAEPhotonList
typedef G4DAEList<G4DAECerenkovStep> G4DAECerenkovStepList

G4DAEPhotonList.hh
G4DAECerenkovPhotonList.hh
G4DAECerenkovStepList.hh
G4DAEChromaPhotonList.hh
G4DAEScintillationStepList.hh
G4DAEScintillationPhotonList.hh
G4DAEPmtHitList.hh
G4DAEPropList.hh

Manual Lists to be migrated to common machinery

G4DAEHit

serializable single hit struct, initialized from indexed elements of G4DAEPhotons with local G4AffineTransform applied separately

G4DAEHitList : G4DAEArrayHolder

adding a G4DAEHit immediately serializes into constituent G4DAEArray

Transport infrastructure

G4DAETransport

holder of various objects and socket for sending/receiving them

G4DAESocket<T> : G4DAESocketBase

Provides separate Send and Receive methods, using template type constructors

G4DAESocketBase

G4DAESerializable* SendReceiveObject(G4DAESerializable* request) const

G4DAESerializable

interface to allow instance transport via G4DAESocket

Array Collection and Transport

G4DAEList<T> : G4DAEArrayHolder

implements G4DAESerializable using capabilities of constituent G4DAEArray

G4DAEArrayHolder : G4DAESerializable

combination of a G4DAEArray and G4DAEMetadata constituents allowing arrays with metadata to be transported via G4DAESocket

G4DAEArray : G4DAESerializable

NumPy (NPY) array serialization/deserialization using numpy.hpp. Effectively allows numpy arrays to be created from C++

G4DAEMetadata : G4DAESerializable

Between process/language communication using JSON strings, python dicts accessible to C++ as map<string,string>

Config and control Infrastructure

G4DAEDatabase

access for inserts and queries to sqlite3 database using RapSQLite

Utililites

G4DAEBuffer

simple byte holder

G4DAECommon

utility functions for md5digest, zmq transport, buffer dumping

G4DAEMap

map<string,string>

G4DAETime

realtime measurement

Geometry

G4DAEGeometry

creates G4DAETransformCache instance by traversing Geant4 volume tree collecting positions (G4AffineTransform) and identifiers of sensitive detector volumes

G4DAETransformCache

Map of SD identifiers to G4AffineTransform with serialization/deserialization functionality. Allows global hit coordinates to be transformed into local PMT coordinates.

TODO: move from cnpy to numpy.hpp

G4DAEMaterialMap

Via mapping between material names and codes, provides lookup array to translate Geant4 material codes into Chroma material codes.

Geant4 Hit Collection Integration

G4DAESensDet : G4VSensitiveDetector

Funnels GPU formed hits into standard Geant4 hit collections.

Normally hits are formed:

bool ProcessHits(G4Step*,G4TouchableHistory*)

Instead bulk hit collection is provided:

void CollectHits(G4DAEPhotons*,G4DAETransformCache*)

Operates via detector specialized constituent G4DAECollector subclass which steals pointers to preexisting hit collections (eg formed by DetDesc/Gaudi)

G4DAECollector

does the work of hit handling, directed by G4DAESensDet

void CollectHits(G4DAEPhotons*, G4DAETransformCache*)

• forms G4DAEHit for each returned photon
• applies local transform for the PmtId obtained from G4DAETransformCache
• subclass implemented detector specific collection

DemoG4DAECollector : G4DAECollector

example of detector specialized hit collector implementing

void Collect(const G4DAEHit& hit)

Daya Bay specializations from DetSimChroma

From NuWa-trunk/dybgaudi/Simulation/DetSimChroma.

DybG4DAECollector : G4DAECollector

subclass handling detector specific hit collection operations steals hit collection pointers and provides a backdoor to populate them

DybG4DAEGeometry : G4DAEGeometry

specializing subclass providing sensor id for location in the geometry tree

size_t TouchableToIdentifier( const G4TouchableHistory& hist )

G4DAEChroma Config and Initialization

Config and Initialization of G4DAEChroma example in DsChromaRunAction_BeginOfRunAction creates and configures constituent instances from envvar strings.

G4DAETransport

envvar configures network or inproc config for ZMQ communication

G4DAEDatabase

envvar configures path to sqlite3 database for performance monitoring

G4DAETransformCache

When run inside NuWa DybG4DAEGeometry used to create G4DAETransformCache, which is persisted to file. When run outside NuWa loads cache from file. This facilitates mocknuwa running, for fast development cycle.

G4DAESensDet

Trojan sensdet that targets victim by name (eg “DsPmtSensDet”). The hit collection pointers of the victim are stolen. SensDet registered with Geant4 to gain access to per event hit collections.

DybG4DAECollector

Provides detector specific hit collection handling, routing hits to the appropriate collections.

Soon to be removed

G4DAETransportCPL.hh
G4DAEPhotonListOld.hh
G4DAEPhotons.hh