Newsgroups: comp.lang.apl
Path: watmath!watserv1!utgpu!news-server.csri.toronto.edu!rpi!usc!elroy.jpl.nasa.gov!jato!csi!sam
From: sam@csi.jpl.nasa.gov (Sam Sirlin)
Subject: Re: Re:  APL execution efficiency revisited
Message-ID: <1992Mar23.185558.2647@csi.jpl.nasa.gov>
Originator: sam@kalessin
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Organization: Jet Propulsion Laboratory, Pasadena, CA
References:  <920322073241_70530.1226_CHC87-1@CompuServe.COM>
Date: Mon, 23 Mar 1992 18:55:58 GMT
Lines: 20


In article <920322073241_70530.1226_CHC87-1@CompuServe.COM>, Mike Kent <70530.1226@CompuServe.COM> writes:
|>  >>[4] Inner and outer products in which most of the entries are        
|>        discarded, or used only as intermediates.
|>  
|>  > This can be almost impossible to avoid ...
|> 
|> No vendor has yet (so far as I know) optimized
|> 
|>     first plus.times / (vector of matrices)

This issue was one of the things Tim Budd tackled with his demand
driven compiler - don't evaluate unneeded intermediate steps. This
particular (APL2?) example won't work, but ISO cases should (assuming 
the compiler works...) 

-- 
Sam Sirlin
Jet Propulsion Laboratory         sam@kalessin.jpl.nasa.gov

