[Maxima-bugs] [ maxima-Bugs-2984863 ] Two problems with specint

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Bugs item #2984863, was opened at 2010-04-10 03:30
Message generated for change (Comment added) made by crategus
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Category: Lisp Core - Integration
Group: None
>Status: Closed
>Resolution: Fixed
Priority: 5
Private: No
Submitted By: Dieter Kaiser (crategus)
Assigned to: Nobody/Anonymous (nobody)
Summary: Two problems with specint

Initial Comment:
Working on the code of hypgeo.lisp I have detected two general problems for almost all implemented special functions. The following is an example.

Maxima does not recognize that the special function does not contain the integration variable. A correct result is bessel_j(0,x)/s.

(%i11) specint(exp(-s*t)*bessel_j(0,x),t);
(%o11) specint(bessel_j(0,x)*%e^-(s*t),t)

Maxima does not recognize that the special function contains the parameter. A correct result is a noun form.

(%i12) specint(exp(-s*t)*bessel_j(0,s*t),t);
(%o12) 1/(sqrt(2)*s)

To correct the first problem the pattern to match the functions have to be more special. The second problem is a bit more difficult to solve. We have to find a general working check, that after scaling the integrand into a form u*exp(-p*t+e*f), u is free of the parameter.

Dieter Kaiser

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>Comment By: Dieter Kaiser (crategus)
Date: 2010-04-10 17:34

Message:
The first problem has been solved with revision 1.77 of hypgeo.lisp. The
pattern to match a special function are more specific.

The second problem is invalid. Of course, the parameter s is a constant of
the integral.

Closing this bug report as fixed for problem 1.
Dieter Kaiser

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