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Re: floating-point efficiency: Lisp vs. Fortran
- To: hmadorf@eso.org
- Subject: Re: floating-point efficiency: Lisp vs. Fortran
- From: moon (David A. Moon)
- Date: Thu, 08 Oct 92 12:14:24 EDT
- Cc: Simon Spero <ses@sunsite.unc.edu>, info-mcl@cambridge.apple.com, info-dylan
> Date: Wed, 07 Oct 92 07:30:35 +0100
> From: hmadorf@eso.org
> ....
> Two versions of the CL code were tested, one without declarations,
> the other fully spiced with declarations. The CL-code was compiled
> with (speed 3) optimization. The Fortran code was not particularly
> optimized. My observations:
>
> 1. Declarations had little influence on CL-execution efficiency.
> .... (I still have to check out
> the optimization document in the /contrib directory in the Apple
> archive.)
This is a digression, however I'll mention it anyway.
It helps if you put in correct declarations. Unfortunately the MCL
compiler does not warn you if you put in declarations that don't make
any difference. If I remember your code, one problem was that you
said integer where you should have said fixnum; a common pitfall in
Common Lisp declarations. I think some other Common Lisp compilers
will tell you whether your declarations are working, which I think
is a good idea.