Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!purdue!haven!ncifcrf!palmer
From: palmer@ncifcrf.gov (Thomas Palmer)
Newsgroups: comp.graphics
Subject: Vectorizing ray-object intersection calculations
Keywords: ray tracing, vectorization
Message-ID: <594@fcs280s.ncifcrf.gov>
Date: 26 Aug 88 15:29:36 GMT
Organization: NCI Supercomputer Center, Frederick, MD
Lines: 13


Has anyone done any work on vectorizing ray-object intersection
calculations?  The vectorizing C compiler on a Cray X/MP will not
(automatically) vectorize loops smaller than about 5 or 6 iterations
(nor should it - the vector register load time outweighs the gain).
Typical ray tracing vector operations involve vectors of length 3 or 4.

  -Tom

 Thomas C. Palmer	NCI Supercomputer Facility
 c/o PRI, Inc.		Phone: (301) 698-5797
 PO Box B, Bldg. 430	Uucp: ...!uunet!ncifcrf.gov!palmer
 Frederick, MD 21701	Arpanet: palmer@ncifcrf.gov