[Maxima-bugs] [ maxima-Bugs-1450722 ] operatorp(expr,derivative)

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Bugs item #1450722, was opened at 2006-03-15 21:40
Message generated for change (Comment added) made by agarate
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Category: None
Group: Fix for 5.9.2
Status: Closed
Resolution: Wont Fix
Priority: 5
Submitted By: Araceli Gárate García (agarate)
Assigned to: Nobody/Anonymous (nobody)
Summary: operatorp(expr,derivative)

Initial Comment:
Hi, the problem is that i need to identify when a
derivative is present. 

(%i211) m:diff(x(t),t);
										 d
(%o211) 									 -- (x(t))
										 dt
(%i212) op(m);
(%o212) 									 derivative
(%i213) if op(m)=derivative then(disp(hi));
(%o213) 									   false
(%i214) if op(m)="derivative" then(disp(hi));
(%o214) 									   false
(%i215) if op(m)=diff then(disp(hi));
(%o215) 									   false
(%i216) if op(m)='derivative then(disp(hi));

the operatorp(m,derivative) doesn't work either. 

Thanks in advance

Araceli Gárate
ga...@ci...


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>Comment By: Araceli Gárate García (agarate)
Date: 2006-03-16 07:15

Message:
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Thank you very much for your quickly answer. 

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Comment By: Robert Dodier (robert_dodier)
Date: 2006-03-16 06:21

Message:
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user_id=501686

Try this --

is (op(m) = nounify(derivative));

if (op(m) = nounify(derivative)) then <do something>;

The problem is that the derivative expression constructed by
diff is a so-called "noun". You have to explicitly make a
noun symbol with nounify, otherwise 'derivative is a verb
symbol. 

Hope this helps, and closing this report as a non-bug.
Robert Dodier

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