Title: Opticks GPU Optical Photon Simulation, highlighting Tools and Techniques 
Speaker：Simon Blyth 
Time: 10:00AM, Oct.31
Place: Room C305,IHEP Main Building
Abstract: 
Opticks replaces Geant4 optical photon simulation on the CPU with an equivalent GPU implementation using the NVIDIA OptiX ray tracing engine, resulting in a drastic speedup in optical photon simulation extrapolated to exceed 1000x Geant4 with workstation GPU machines. Generation steps of photons are collected from Geant4 and copied to the GPU allowing optical photons to become fully GPU resident, being generated and propagated entirely on the GPU with only detected photons requiring memory allocation on the CPU. GPU development of the Opticks optical photon simulation has required a first principals approach to techniques such as ray geometry intersection and Monte Carlo sampling and has necessitated the use of uncommon tools such as NumPy, CUDA and Thrust. The presentation will highlight these tools and techniques as well as covering Opticks itself, with the aim of providing an introduction to the power and ease of an alternative NumPy based toolset that can be directly useful for any data analysis. 
If you wish to apply GPU acceleration to speedup any algorithm or to simply analyse C++ generated data from the comfort of python then my presentation will provide much to interest you. 

About the speaker: 
Simon Blyth received his D.Phil degree from Oxford University working on the DELPHI experiment at CERN on radiative muon decays. He continued at LEP on the L3 experiment as a Research Associate with Carnegie Mellon based at CERN, making the best L3 measurement of the forward-backward asymmetry of b quarks as well as managing the L3 luminosity detector and analysis. In 2002 he joined the Belle group at the National Taiwan University measuring six color suppressed B meson decay branching fractions. Subsequently he transitioned to the Daya Bay experiment, with National United University in Taiwan working on database management and software infrastructure development vital to Daya Bay. Returning to National Taiwan University in 2013 as he set himself the goal of solving the optical photon simulation problem faced by PMT based experiments using an innovative GPU based approach.