Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!samsung!emory!hubcap!murray
From: murray@sun13.scri.fsu.edu (John Murray)
Newsgroups: comp.parallel
Subject: Re: Visualization Machines
Keywords: Silicon Graphics, Connection Machine CM-2
Message-ID: <9834@hubcap.clemson.edu>
Date: 25 Jul 90 13:14:03 GMT
Sender: fpst@hubcap.clemson.edu
Followup-To: comp.unix.cray
Organization: SCRI, Florida State University
Lines: 60
Approved: parallel@hubcap.clemson.edu


In article <9811@hubcap.clemson.edu> malcolm@Apple.COM (Malcolm Slaney) writes:
>What are good machines for scientific visualizations?  We have a Cray but
>I'm looking around for other machines that can do my work nearly as fast.
>
>My research (models of human hearing) can support parallelism and lots of
>vectorization.  I want to be able to compute something and then display the
>result very quickly (20 frames per second) on a monitor.

It really depends on what sorts of visualizations you want to do. Do you just
want to plop some big 2D scalar array on the screen? Or do you want 3D objects
with smooth shading and lighting models? 

>I guess the numbers that are important to me are >100 MFlops of peak 
>performance and > 25 Mega-pixels per second output rate (at the same time.)
>
>Should I think about Convex?  What about the new Connection Machine?  Machines
>like the DAP and the MassPar seem to be too hard to program (I want to do
>new research in hearing, not algorithm development.)

We have a Connection Machine CM-2. (64K processors, 256Kbits/proc) I have
been having a wonderful time trying to do something useful with the graphics
interface. The framebuffer data channel runs at 80Mbyte/second, but tuning
a given program to get it to display anything at 20 frames/sec is a hefty
challenge. Tuning a 3D rendering program to run at 20/sec might finally get
me my masters... maybe a doctorate too :-)

If you are doing complex graphics, you might be much better off with a current
graphics work-station. Our Silicon Graphics IRIS-4D/240-GTX runs standard
(not "tuned") programs at 10MFlop (real ones, not peak) per processor, and
there are 4 processors on ours, can be up to 8 * . The graphics hardware
processes about 40K smooth-shaded fully-lit polygons per second, again real
ones - the salesmen say 100K lit, shaded polygons/sec.

If this isn't enough, SGI's newest, the 300 series, has a 33% faster clock
and much better graphics hardware. Up to eight processors, like the 200's.
Also, there exist some mechanisms for remote displays - not just X-windows,
fortunately - so with a fast enough data path you could be doing your math
on a Cray and your 3D displays on an IRIS, real time.

A final note on the CM-2: Thinking Machines IS working on greatly improving the
graphics capabilities of the CM-2, but if you're not looking for a "Real Soon
Now(tm)" solution...

>							Malcolm Slaney
>							Apple Perception Group
>							malcolm@apple.com

* I have no idea if it's possible to parallelize something across multiple
processors on the 4D series. I've never needed to try it.

Disclaimer #1: I don't work for Silicon Graphics or TMC, I'm merely a satisfied
		user, etc., etc.
Disclaimer #2: I do work for SCRI, but I sometimes wonder if they realize it.
Meta-Disclaimer: "A society that needs disclaimers has too many lawyers"
		  - Eric Pepke

John R. Murray          | "They call me Mr. Know-it-all, I am so eloquent.
murray@vs2.scri.fsu.edu |  Perfection is my middle name!
                        |   ...and whatever rhymes with 'eloquent'." - Primus