ITK/Release 4/Refactor Numerical Libraries/Inventory

In this page we collect an inventory of numerical libraries in ITK base on the state of the code at the ITKv4-Alpha09 Git tag.

ITK Numerical Needs

ITK needs for numerical libraries fall in the following broad categories

• Fourier Transforms
• Non-Linear Optimization
• Linear Solvers
  • Dense Matrices (typically small, less than 100x100)
  • Sparse Matrices
  • Large Sparse Matrices (e.g. FEM type problems)
• Matrix Vector Operations
  • A lot of them are
    • Matrix . Matrix operations (for matrix size 2x2, 3x3, 4x4, 3x4)
    • Matrix . Vector operations (for matrix size 2x2, 3x3, 4x4, 3x4)
• Special Functions
  • Modified Bessel Function of the first kind
    • Important for computing the discrete Gaussian kernel
• Accumulation of Rounding Errors

Architecture

• ITK is focused on shared memory systems
  • Multi-Core machines
  • Exploits Multi-threaded implementations

Profiling Targets

The following problems have been selected as interesting targets for profiling performance.

3D Registration

• ITK/Examples/Registration/ImageRegistration8.cxx
  • Led to identify a bottleneck on the allocation and deallocation of Jacobian Matrices
    • Work In Progress patch here: http://review.source.kitware.com/#change,2774

Demons Registration

• ITK/Examples/Registration/DeformableRegistration10.cxx

BSpline Registration

• ITK/Examples/Registration/DeformableRegistration15.cxx

Level Sets

• ITK/Examples/Registration/GeodesicActiveContourImageFilter.cxx

Portability

ITK is intended to work in the most popular platforms.

More specifically

• Windows
• Linux
• Macs

With commonly used compilers

• Visual Studio 7.1 to 10
• GCC 3.4 to 4.6
• Intel Compiler
• Sun CC compiler

A more detailed list of supported compiles can be found here:

• Modern C++

Libraries Used

• Work in progress...