Welcome to k4megat dive-series documentation!

The Dive-series aims to provide k4megat developers a deep insight into the building blocks of k4megat software, i.e.:

• DD4hep

• EDM4hep

• Gaudi

They are based on my learning notes, and no guarantee that they are correct (since they are based on my personal knowlegebase). But, I think they are still valuable to give you a quick overview. The official documentation and some published paper and talk should still be a developer’s main reference sources. And the original source code is the final auditor.

Note

Some links may be invalid since they point to a local filesystem path in my personal computer. This is due to the fact the documents are exported from my org-mode notes. Clean-up is definely needed in the future.

Contents

• Dive into DD4hep
  • 1 Disclaim
  • 2 DDCore
    • 2.1 Detector description
      • 2.1.1 Overview
      • 2.1.2 Design
      • 2.1.3 Access Detector instance
      • 2.1.4 Use Detector instance
        • 2.1.4.1 top-level (the level under world) access
        • 2.1.4.2 tree tranversal
      • 2.1.5 compact xml
        • 2.1.5.1 top-level tags and parsing sequence
      • 2.1.6 Detector definition
      • 2.1.7 TODO Build type
      • 2.1.8 Plumbing utilities to build geometry primitives
        • 2.1.8.1 <shape>
        • 2.1.8.2 <volume>
        • 2.1.8.3 <envelope>
        • 2.1.8.4 <transformation>
      • 2.1.9 CAD model
        • 2.1.9.1 CAD shape
        • 2.1.9.2 CAD volume
      • 2.1.10 General-purpose detector-builder plugin
      • 2.1.11 Class diagram
    • 2.2 Checklist building geometry tree
    • 2.3 Post-processing
      • 2.3.1 Overview
      • 2.3.2 Useful post-processor plugins
    • 2.4 DetElement
      • 2.4.1 Overview
      • 2.4.2 Useful properties
      • 2.4.3 Category of detector
    • 2.5 Volume-related Data
      • 2.5.1 Volume Extension
      • 2.5.2 PlacedVolume Extension
      • 2.5.3 VolumeID and VolumeManager
        • 2.5.3.1 VolumeManagerContext
    • 2.6 TODO SensitiveDetector
      • 2.6.1 overview
      • 2.6.2 Readout & Segmentation
      • 2.6.3 IDDescriptor & BitFieldCoder
    • 2.7 TODO Field
    • 2.8 Material
    • 2.9 Persistence
    • 2.10 Visualization
      • 2.10.1 Native method
      • 2.10.2 Utility apps
    • 2.11 Apps
    • 2.12 TODO Other Data Structures
      • 2.12.1 Condition data
      • 2.12.2 Alignment data
  • 3 TODO DDG4
    • 3.1 Kernel Access
    • 3.2 Multi-Threading
  • 4 TODO DDDigi
  • 5 DDRec
    • 5.1 CellIDPositionConverter
    • 5.2 Surface
      • 5.2.1 Overview
      • 5.2.2 Data classes
      • 5.2.3 Management classes
      • 5.2.4 Add surface
      • 5.2.5 Use surface
      • 5.2.6 Class diagram
  • 6 TODO DDAlign
    • 6.1 Alignment procedure
  • 7 TODO DDCond
  • 8 Utilities
    • 8.1 Versioning
  • 9 Kernel of the core
    • 9.1 Object Model of DDCore
      • 9.1.1 Using Handle
    • 9.2 TODO Plugin Framework
      • 9.2.1 Rationale
      • 9.2.2 Overview
      • 9.2.3 Internals
        • 9.2.3.1 main classes
        • 9.2.3.2 thread-safety implementation
    • 9.3 Extension Mechanism
      • 9.3.1 Overview
      • 9.3.2 How to use
      • 9.3.3 List of useful extension data class
      • 9.3.4 Class diagram
    • 9.4 TODO Callback mechanism
  • 10 Programming idioms
• Dive into EDM4hep
  • 1 Features
• Dive into Gaudi
  • 0.1 Plugin Service and Factory
  • 0.2 Value Semantics and Ownership Management
    • 0.2.1 idoms
      • 0.2.1.1 copy-swap and copy-elison
      • 0.2.1.2 reference-counting
      • 0.2.1.3 handle-body (AKA: pointer to implementation)
  • 0.3 Parallelism
    • 0.3.1 Multi-Process
    • 0.3.2 Multi-Thread
    • 0.3.3 Multi-Job
    • 0.3.4 Multi-Node??
  • 0.4 Finite State Machine (FSM)
  • 0.5 Curiously Recurring Template Pattern (CRTP)
  • 1.1 Concurrency
    • 1.1.1 GaudiHive (MT)
    • 1.1.2 GaudiMP (MP)
  • 1.2 Interface
    • 1.2.1 IService
    • 1.2.2 IProperty
    • 1.2.3 ITool
    • 1.2.4 IStateful
  • 2.1 overview
  • 2.2 Config2
  • 2.3 Histogram
  • 3.1 As separate external installation
    • 3.1.1 View-based version control?
    • 3.1.2 A package stack installation script which provides a view
  • 3.2 As internal sub-project
    • 3.2.1 cmake external project?