[Maxima-bugs] [ maxima-Bugs-2036462 ] Very long calculation time, normal ?

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Bugs item #2036462, was opened at 2008-08-03 08:34
Message generated for change (Comment added) made by jnevins32
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Category: Lisp Core - Solving equations
Group: None
Status: Open
Resolution: None
Priority: 6
Private: No
Submitted By: thbesson (thbesson)
Assigned to: Nobody/Anonymous (nobody)
Summary: Very long calculation time, normal ?

Initial Comment:
wxMaxima 0.7.5 http://wxmaxima.sourceforge.net
Maxima 5.15.0 http://maxima.sourceforge.net
Using Lisp GNU Common Lisp (GCL) GCL 2.6.8 (aka 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) kill(all);
(%o0) done
(%i1) declare(a,constant);
(%o1) done
(%i2) declare(b,constant);
(%o2) done
(%i3) declare(c,constant);
(%o3) done
(%i4) solve(a*x^4/4!+a*x^2/2!+b*x-%pi*b+a+c);

running since 12 hours on a dualcore

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Comment By: Jason Nevins (jnevins32)
Date: 2008-09-01 22:52

Message:
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Hi, thanks, workaround helped.

Also, I have realized that I had support compiled for multiple Common Lisp
interpreters. Will try to reduce this to only one and see if it makes a
difference.

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Comment By: Jason Nevins (jnevins32)
Date: 2008-09-01 22:32

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Hi

I'm Having exact same problem (see: 2087495).

Also when doing exactly the above the problem is reproduced.

Maxima 5.16.2 http://maxima.sourceforge.net
Using Lisp CLISP 2.43 (2007-11-18)
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) declare(a,constant);
(%o1)                                done
(%i2) declare(b,constant);
(%o2)                                done
(%i3) declare(c,constant);
(%o3)                                done
(%i4) solve(a*x^4/4!+a*x^2/2!+b*x-%pi*b+a+c);
<<<<<<<<<<<<<<<<<<<< HANGS HERE.

Regards
Jason Nevins

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Comment By: Robert Dodier (robert_dodier)
Date: 2008-08-03 20:24

Message:
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user_id=501686
Originator: NO

Assign category.

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Comment By: Robert Dodier (robert_dodier)
Date: 2008-08-03 18:58

Message:
Logged In: YES 
user_id=501686
Originator: NO

Well, this is a bug.

Here is a workaround: omit the declare(..., constant) and tell solve to
solve for x specifically.

solve(a*x^4/4!+a*x^2/2!+b*x-%pi*b+a+c, x);
 => (quickly returns a long expression)

I can't tell what is the problem here; simpler examples seem to get solved
right away.

I've moved this to the bug tracker in hope of eventually resolving it.

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