[Maxima] Improper integral change in 5.20?

Karl-Dieter Crisman kcrisman at gmail.com
Tue Dec 22 09:55:50 CST 2009


Yes, I see what is going on - before Maxima was perhaps using the
limit as n->infinity of f(x)-f(-x), where f is an indefinite integral?
 We just report 'divergent' if we get the principal value statement.
Thank you for your help; we will have to make sure this doesn't stay
in the test suite as is!

On 12/22/09, Stavros Macrakis <macrakis at alum.mit.edu> wrote:
> Under the standard definitions, I believe this integral is divergent, so the
> new answer is better than the old.  In some cases, Maxima reports the
> 'principal value' of such integrals, with a warning message, which is
> problematic because it's not clear how to communicate the warning
> programmatically to systems like Sage.
>
>              -s
>
>
> On Tue, Dec 22, 2009 at 10:26 AM, Karl-Dieter Crisman <kcrisman at gmail.com>
> wrote:
> >
> > We are hoping to upgrade the version of Maxima in Sage to 5.20, to
> > take advantage of a number of recent improvements (particularly in
> > solving).  I am finding the following possible regression from 5.19.1
> > to 5.20.0 (also in 5.20.1):
> >
> > 5.19.1
> > (%i1) integrate(x*cos(-y*x),x,minf,inf);
> > (%o1) 0
> >
> > 5.20.0
> > (%i1) integrate(x*cos(-y*x),x,minf,inf);
> > (%o1) <ascii art indicating the integral is returned as a nounform>
> >
> > This is with SBCL and ECL; I've logged it at
> >
> http://sourceforge.net/tracker/?func=detail&aid=2919396&group_id=4933&atid=104933
> >
> > If there is an obvious easy patch for this, we can apply it ourselves
> > for now and still put 5.20.1 in soon, which we would like to.  Thanks
> > for any assistance you can provide so close to the holidays!
> > _______________________________________________
> > Maxima mailing list
> > Maxima at math.utexas.edu
> > http://www.math.utexas.edu/mailman/listinfo/maxima
> >
>
>


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