Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!swrinde!elroy.jpl.nasa.gov!ames!uhccux!munnari.oz.au!brolga!bunyip.cc.uq.oz.au!marlin.jcu.edu.au!csrdh From: csrdh@marlin.jcu.edu.au (Rowan Hughes) Newsgroups: comp.arch Subject: Re: Vector vs Cache/Superscalar Message-ID: <1991May6.035310.26794@marlin.jcu.edu.au> Date: 6 May 91 03:53:10 GMT References: <1991May4.031835.7979@midway.uchicago.edu> Organization: James Cook University Lines: 17 >raymond> (b) Tridiagonal solving. Comes up in lots of codes, and it is >raymond> a real vector-breaker. In fact, vector machines choke on all >raymond> sorts of recursion, whereas the superscalars just love them. >raymond> On the RS/6000, the tridiag code basically vanished, whereas on >raymond> the vector Stardent, it was a bottleneck. The latest Fujitsu compiler (for the VP2000 series) will handle 1st order backwards recurrence, ie A(I)=A(I-1)+B(I), as well as the usual forward recurrence, in full vector mode. Many old scalar problems can now be vectorized. I'd be interested to hear if Cray/ETA/Alliant etc have this capability too. -- Rowan Hughes James Cook University Marine Modelling Unit Townsville, Australia. Dept. Civil and Systems Engineering csrdh@marlin.jcu.edu.au