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From: jbn@glacier.UUCP
Newsgroups: comp.lang.lisp
Subject: LISP floating point performance
Message-ID: <16921@glacier.STANFORD.EDU>
Date: Mon, 2-Mar-87 02:41:16 EST
Article-I.D.: glacier.16921
Posted: Mon Mar  2 02:41:16 1987
Date-Received: Tue, 3-Mar-87 20:21:48 EST
Organization: Stanford University
Lines: 18
Keywords: floating point, efficiency, LISP


    Floating point computations in current LISP implementations tend to
be unnecessarily slow.  While PDP-10 MACLISP may have exhibited excellent
floating point performance, several of today's popular LISP implementations
definitely do not.  Although Common LISP contains means of providing the
compiler with enough information to permit the generation of in-line code
for floating point operations, many compilers do not use this information
effectively.

    So I pose the following question:
    Is there a Common LISP for SUN or VAXen which, given enough declarations,
will generate code for, say, a matrix multiply which does not contain any
subroutine calls, boxing, unboxing, storage allocation, type checking, tests,
stack manipulation, or other unwanted fooling around within the inner loop?
I'm not asking for the strength reductions for nested loops one expects from
a good FORTRAN compiler; just good clean code.
    
					John Nagle