Exponentiation used in division? & Some extrordinary slowness is some problems.
Subject: Exponentiation used in division? & Some extrordinary slowness is some problems.
From: Dennis Darland - student
Date: Tue, 31 Dec 2013 02:57:37 -0600
Exponentiation is very inefficient compared to division!
Why is it used here in maxima? (or appear to be)
Example:
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Maxima 5.30.0 http://maxima.sourceforge.net
using Lisp GNU Common Lisp (GCL) GCL 2.6.8 (a.k.a. GCL)
Distributed under the GNU Public License. See the file COPYING.
Dedicated to the memory of William Schelter.
The function bug_report() provides bug reporting information.
(%i1) (4.0/0.0);
expt: undefined: 0 to a negative exponent.
-- an error. To debug this try: debugmode(true);
(%i2)
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I do not expect maxima to be comparable to c at number crunching,
but there are two examples in my tests that it appears would take over
one day to complete using maxima, but take only 4 and 5 seconds
respectively in c. Most of my tests take under one minute even in maxima.
The algorithms are the same for maxima and c.
As I don't know the internals of maxima, I cannot tackle it. Perhaps it
is worth someones time to look into. I wouldn't be surprised if it were
related to the problem above, but do not know.
My test results and source code are at:
http://sode.sourceforge.net/
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Dennis Darland
student at dennisdarland.com