clarke@csri.toronto.edu (Jim Clarke) (01/26/89)
GRAPHICS SEMINAR - Tuesday, January 31, 3 p.m. in Room GB 120 (GB = Galbraith Building, 35 St. George Street) Marie-Claire Forgue Universite de Nice Laboratoire de Signaux et Systemes (LASSY). "Ray-tracing parallelization on a SIMD/SPMD machine" The goal of this thesis is to implement a ray-tracing algorithm on the OP- SILA vector/parallel machine. This machine offers two operating modes, SIMD (Single Instruction Multiple Data) and SPMD (Single Program Multiple Data), which coexist and cooperate. In our application, we used a mixed-mode pro- gramming approach, using SPMD mode to perform calculations, and SIMD mode to exchange information between processors. The communication protocol is structured by use of ray-packets. We used vectorial indirect access primi- tive called "Scatter" to perform the packet exchange. However, the use of a synchronous interconnection network causes the phase of communication to be delayed. Because of the unavoidable work disparity among processors, this leads to a decrease in global efficiency. -- Jim Clarke -- Dept. of Computer Science, Univ. of Toronto, Canada M5S 1A4 (416) 978-4058 BITNET,CSNET: clarke@csri.toronto.edu CDNNET: clarke@csri.toronto.cdn UUCP: {allegra,cornell,decvax,linus,utzoo}!utcsri!clarke