[Maxima-bugs] [ maxima-Bugs-1162505 ] specint returns Lisp symbol other-defint-to-follow-negtest

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Bugs item #1162505, was opened at 2005-03-13 18:13
Message generated for change (Comment added) made by crategus
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Category: Lisp Core
Group: None
>Status: Closed
Resolution: None
Priority: 5
Private: No
Submitted By: Robert Dodier (robert_dodier)
Assigned to: Nobody/Anonymous (nobody)
Summary: specint returns Lisp symbol other-defint-to-follow-negtest 

Initial Comment:
specint returns a Lisp symbol,
other-defint-to-follow-negtest, when it fails. Example:

  specint (1/(1+exp(-u)),u);  
yields other-defint-to-follow-negtest

   specint (1/(1+exp(-u))*exp(-s*u),u); 
yields other-defint-to-follow-negtest

The return value should be a noun in these cases,
although it's not clear what the noun should be --
integrate or specint ?? My suggestion is that the
return value should be an integrate noun (with the
limits of integration specified as zero and infinity).


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>Comment By: Dieter Kaiser (crategus)
Date: 2008-08-06 13:07

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The code is changed as suggested.
Closing the bug report.

Dieter Kaiser

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Comment By: Dieter Kaiser (crategus)
Date: 2008-07-18 22:49

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The changed code of $specint (Rev. 1.40) gives for the second integral of
this bug report a noun form, but the symbol
'other-definit-to-follow-negtest for the first integral.

The reason is, that the routine NEGTEST don't signal the return of a noun
form.

With the introduced global flag *hyp-return-noun-form-flag* this can be
easy corrected:

===================================================================
RCS file: /cvsroot/maxima/maxima/src/hypgeo.lisp,v
retrieving revision 1.40
diff -u -r1.40 hypgeo.lisp
--- hypgeo.lisp   4 Jul 2008 14:12:52 -0000   1.40
+++ hypgeo.lisp   18 Jul 2008 20:34:55 -0000
@@ -1108,7 +1108,8 @@
                 ;; We forget the rule after finishing the calculation.
                 (mfuncall '$forget `((mgreaterp) psey 0))))))
 
-     (return 'other-defint-to-follow-negtest)))
+     (return 
+       (setq *hyp-return-noun-form-flag*
'other-defint-to-follow-negtest))))
===================================================================

The results after the change are:

(%i6) specint(1/(1+exp(-u)),u);
(%o6) specint(%e^u/(%e^u+1),u)
(%i7) specint(1/(1+exp(-u))*exp(-u),u);
(%o7) specint(1/(%e^u+1),u)

There a lot of other places this mechanism can be used to create a nice
noun form.

Should I commit this change? After this change the bug report could be
closed.

Dieter Kaiser

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Comment By: Raymond Toy (rtoy)
Date: 2005-03-14 22:55

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Since integrate doesn't know about Laplace transforms, I
would prefer specint be used since that's what I typed.

Having said that, I think specint was never really finished
and needs more work, and I rather like the symbols because
they tell me at least where to look to find out why it
failed.  specint is complicated enough that this little bit
of info is rather nice.

Eventually, though, a noun form should be returned.

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