Detector Description Framework in LHCb S é bastien Ponce CERN

CHEP 2003 - 3/21/03

Detector DescriptionFramework in LHCb

Sébastien PonceCERN

2/21CHEP 2003 - 3/21/03Sébastien Ponce

Topics

● Detector data overviewDetector data overview● Structure, Transient Store, XML backend

● Possible extensionsPossible extensions● Parameters, Full extension

● Condition DatabaseCondition Database● Purpose, Implementation, Impact on user

● ToolsTools● Simulation, Geometry Checker, Visualization


Data Diagram

Structure

MaterialGeometry

DetElem GeometryInfo

CalibrationConditionAlignmentConditionReadoutCondition

MuonStation

EcalClusterCondition

Conditions

EcalClusterCondition

MuonStationAlignment

VeloReadout

Lvolume

Pvolume

Solid

Box

Sphere

*

Points to

Inherits fromResolved on demand Material

Isotope Mixture

Element


Transient Store

● Tree-like structure● Items identified by a logical name

● Load/update on demand● Automatic update when new event

Transient Store

LvolumeLvolumeLvolumeDetElem GeometryDb

DetectorData Service

PersistencyService

Algorithm

Ask forObject

Retrievepointer

Checkpresence LoadAsk creation

Cnv


XML Backend

● Easy to read and to parse● Extensible● Easy to convert● Many tools● Extended using references

<subtraction name="sub2"> <box name="box3“ sizeX="1*m“ sizeY="1*m“ sizeZ="15*cm"/> <tubs name="tub2“ outerRadius="15*cm“ sizeZ="25*cm"/></subtraction><posXYZ z="-40*cm"/><rotXYZ rotX=“90*degree”/>

protocol://hostname/path/file.xml#ObjectIDprotocol://hostname/path/file.xml#ObjectID

<detelemref href="LHCb/structure.xml#LHCb"/>

CHEP 2003 - 3/21/03

User Extensions


User Extensions

● Why ?● In order to implement specific behaviour

(e.g. answering specific simulation questions)● Add specific information to elements / conditions

● How ?● By specializing the Detector Element / Condition● 3 main possibilities :

● Usage of parameters in the XML code● Specialization of the C++ object only● Full extension, including XML, DTD and C++

converters


Parameter Extension

<detelem name="MStation01"> <param name="Al_thickness" type="double"> 1.2222*mm <param></detelem>

SmartDataPtr<IDetectorElement> station (detSvc(), "/dd/Structure/LHCb/Muon/MStation01");std::cout << station->param("Al_thickness");

SmartDataPtr<IDetectorElement> station (detSvc(), "/dd/Structure/LHCb/Muon/MStation01");std::cout << station->param("Al_thickness");

● Definition of parameters (name, type and value) in the XML code

● Vectors of parameters also allowed● Direct and easy access in C++


C++ Class Extension

● New C++ class inheriting from DetectorElement

● Any member or method may be added

● Its initialize method is called by the framework.

● A dummy converter is needed (2 lines)

class MyDetElem : public DetectorElement {

int getChannelNb() { return chNb; }

StatusCode initialize() { chNb = paramAsInt (“ChNb”); return SUCCESS; }

private : int chNb;}

static CnvFactory <XmlUserDetElemCnv<MyDetElem>> s_factory;const ICnvFactory& XmlMyDetElemCnvFactory = s_factory;


Full Extension

● Extension of the DTD to define new XML elements inside the <specific> element

● Parsing of the new XML code using dedicated converters

● Still specialized C++ objects

<detelem name="Head"> <specific> <channelSet name="Controls"> <channels name=”in” nb="20"/> <channels name=”out” nb="150"/> </channelSet> </specific></detelem>

<detelem name="Head"> <specific> <channelSet name="Controls"> <channels name=”in” nb="20"/> <channels name=”out” nb="150"/> </channelSet> </specific></detelem>

if ("channels" == elementName) { string name = childElement.getAttribute ("name"); int nb = xmlSvc()->eval(childElement.getAttribute("nb")); currentChannelSet->addChannel(name, nb);}

if ("channels" == elementName) { string name = childElement.getAttribute ("name"); int nb = xmlSvc()->eval(childElement.getAttribute("nb")); currentChannelSet->addChannel(name, nb);}

CHEP 2003 - 3/21/03

Condition Database


CondDB Purpose

Data ItemData Item

TimeTime

VersionVersion

● To deal with time varying data like calibration, alignment, environment (temperatures) ...

● Handle several versions of a given data● Also deal with the geometry, which is also time

dependent (longer period though)


CondDB Implementation

Transient Store

DetElemDetElemDetElemDetElem

DetectorData Service

PersistencyService

Algorithm

Ask forObject

Retrievepointer

Checkpresence Ask creation

Cnv

ConditionDb

ConditionService

Ask for data Retrieve themfrom Database

Abstract interface

● Additional service of the framework● Independent of the type of data contained (XML)● Based on an abstract interface with several

possible backends (Objectivity, ORACLE, MySQL)

Impact on End User

● No impact on the "raw" XML code● Only references are changed by the usage of the

"conddb" protocol● No change at all in the C++ code : the correct data

are loaded depending on the event time

<DDDB> <catalog name="Hcal">  <conditionref href="conddb:/CONDDB/SlowControl/Hcal/scHcal#scHcal"/> </catalog></DDDB>

<DDDB> <catalog name="Hcal">  <conditionref href="conddb:/CONDDB/SlowControl/Hcal/scHcal#scHcal"/> </catalog></DDDB>

CHEP 2003 - 3/21/03

Tools


XmlEditor Tool

● Specialized XML Editor for Detector data● Understanding cross file references● Hides the complexity of XML from the end user

● Tree like structure a la explorer● Easy drag & drop, cut & paste● Insure that the XML is well-formed and valid● Still writes human readable, indented XML


XmlEditor Tool


Geometry Checkers

● Visual checker :● based on David :

Dawn's Visual Intersection Debugger

● Uses GiGa :Gaudi interface to Geant4 applications

● Gaudi Transport Service :

● More precise

● More reliable


Visualization Tool

● Event and geometry viewer● Interfaced with Gaudi via scripting services


Visualization (2)


Conclusion

● A fully functional and stable solution● Many tools provided :

● For XML generation● For geometry checking● For visualization

● Used successfully for simulation, reconstruction and analysis

Detector Description Framework in LHCb S é bastien Ponce CERN

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