ITK/Release 4/Modularization

Modularization

Goals

• Organize the continuous growth of the Toolkit
  • Create system with a kernel base code and topic modules
  • Kernel very rigorously supported and developed
  • Possibly two classes of modules: Core and Extra
  • Core modules also rigorously supported
  • Extra modules less so
• Simplify usage for application developers
  • Package manager that allows user to choose exactly what functionality is desired
  • Modules exist along logical boundaries

Issues

• Automatic code analysis and initial segmentation
  • Develop accurate graph of code dependencies
    • Use "#include" as edge in graph
    • Need to remove unnecessary includes (non-trivial problem)
  • Segment the code into a kernel and modules
    • Use graph clustering/segmentation methods
    • Develop good cost function for the segmentation
    • High cost for code in the kernel
    • High cost for weak modular dependencies
• Manual segmentation improvement
  • Ensure that modules divided logically
  • Good granularity so that modules provide a benefit
    • Too many modules is too complex
    • Too few modules is pointless
    • Goal: ~20 modules
  • Only logical modular dependencies
    • "Advanced Registration" depends on "Registration" is OK
    • "Segmentation" depends on "Registration" because they share one non-kernel file is BAD

Tools

• Ryppl
  • http://ryppl.org/
  • Package Manager - Multi-Platform
    • Requirements

• Source Navigator
  • http://sourcenav.berlios.de/
  • Static analysis tool
  • Builds detailed database of code elements and interactions
  • Programmable tcl API (also c++ but less well documents and/or out of date)