Update on VASST

1
Update on VASST

• Meant for computation intensive tasks also good
  for applications deal with huge date set.
• GCC/ICC installed on it.
• VTK/ITK have been built on it using gcc/icc.
• Gcc build is straight forward as other linux
  build when using cmake. When build using icc, use
  O2 otherwise causes compilation errors.
• So far we do not have a job scheduling system so
  be careful on how many processors you use.

2
VTK/ITK Quality dashboard

• It is a testing system used to run tests and post
  results on the VTK/ITK quality dashboard. We
  added our Altix/icc configuration into the
  dashboard to let developers be aware of any
  problem specific for this configuration.
• VTK dashboard for Altix/icc has been up for
  several months.
• ITK dashboard for Altix/icc was just started.

3
Multi-threading in VTK/ITK

• Fact most imaging filters in VTK/ITK are
  multi-threaded. Look for vtkImageThreadedAlgorithm
  (VTK) and itkImageSource(ITK)
• The number of threads is set the number of
  processors by default
• We are looking at image registration algorithm
  and trying to multi-thread some of them.
• Example itkMutualInformationImageToImageMetric
• Thread safety VXL uses netlib and it is not
  clear if it is thread safe so far.

4
VTK/ITK threading model
algorithm
cpu1
output
Input volume
cpu2
5
Other multi-threading techniques

• VTK/ITK mutli-threading techniques are based on
  Pthread model.
• OpenMP is another way for multi-threading. It is
  only available in icc, not gcc.
• Message Passing Interface(MPI) is meant for
  distributed computing. Altix is a shared memory
  architecture. But there is a SGI MPI API on it
  called MPT.

6
Computation library

• Freely available lib netlib
• www.netlib.orgwww.netlib.org
• SGI computation library SCSL
• Signal processing routines FFT Convolution
  Correlation.
• Direct linear equation solvers
• Lapack and blas

7
Prism graphics system

• Hardware 8 Intel Itanium CPUs 4 ATI Fire GL
  graphics boards image compositor.
• Software SGI advanced Linux SGI OpenGL
  Multipipe environment ( with SGI image compositor
  ) SGI OpenGL volumizer2 API.
• Difference between vasst and prism Meant to be a
  graphics system, similar hardware and software
  environment. Basically programs developed for
  vasst can be run directly on prism.

8
OpenGL Multipipe Environment
9
SGI OpenGL Volumizer API

• Uses 3D texture mapping technique for volume
  rendering
• Currently I am working on integration of it with
  VTK.
• Tested the Volumizer sample programs and found a
  bug for specular shading. SGI just confirmed this
  bug and said it will be fixed in their next
  release.
• Other volume rendering methods ray casting(
  multi-threaded) shear-warp( not working) 2D
  texture mapping.

10
Documentations

• Intel compilers
• /opt/intel_cc_80/doc/
• SGI techpub library(http//techpubs.sgi.com)
• SCSL
• OpenGL Multipipe
• OpenGL Volumizer
• www.imaging.robarts.ca/kwang

11
Questions?

• You are welcome to use vasst for computation
  intensive task and prism for visualization task.
• Think your algorithm might be able to take
  advantage of multi-theading?