Opened 4 years ago

Last modified 10 months ago

#17469 new defect

Maxima doesn't do an integral we thought was fixed

Reported by: kcrisman Owned by:
Priority: major Milestone: sage-6.5
Component: calculus Keywords:
Cc: Merged in:
Authors: Reviewers:
Report Upstream: Fixed upstream, but not in a stable release. Work issues:
Branch: Commit:
Dependencies: Stopgaps:

Description

#11238 is back.

;;; Loading #P"/Users/.../sage/local/lib/ecl/sb-bsd-sockets.fas"
;;; Loading #P"/Users/.../sage/local/lib/ecl/sockets.fas"
;;; Loading #P"/Users/.../sage/local/lib/ecl/defsystem.fas"
;;; Loading #P"/Users/.../sage/local/lib/ecl/cmp.fas"
Maxima 5.34.1 http://maxima.sourceforge.net
using Lisp ECL 13.5.1
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) display2d:false
;

(%o1) false
(%i2) integrate(exp(-x)*sinh(sqrt(x)),x,0,inf);

(%o2) -%e^(1/4)*(2*gamma_incomplete(1,1)-gamma_incomplete(1/2,1)-sqrt(%pi)-2)/4
 +%e^(1/4)*gamma_incomplete(1,1)/2-%e^(1/4)*gamma_incomplete(1/2,1)/4
 +%e^(1/4)*sqrt(%pi)/4-%e^(1/4)/2
(%i3) domain:complex;

(%o3) complex
(%i4) integrate(exp(-x)*sinh(sqrt(x)),x,0,inf);
^C
Maxima encountered a Lisp error:

 Console interrupt.

Automatically continuing.

Change History (6)

comment:1 Changed 4 years ago by kcrisman

To be precise,

sage: integrate(exp(-x)*sin(sqrt(x)), x, 0, oo)
integrate(e^(-x)*sin(sqrt(x)), x, 0, +Infinity)

This did work in Sage 5.2.

sage: integrate(exp(-x)*sinh(sqrt(x)), x, 0, oo)
1/2*sqrt(pi)*e^(1/4)
Last edited 4 years ago by kcrisman (previous) (diff)

comment:2 Changed 4 years ago by kcrisman

  • Summary changed from Maxima hangs on an integral we thought was fixed to Maxima doesn't do an integral we thought was fixed

comment:3 Changed 4 years ago by kcrisman

  • Report Upstream changed from N/A to Reported upstream. No feedback yet.

comment:4 Changed 4 years ago by kcrisman

Current doctest for this bites.

    Another symbolic integral, from :trac:`11238`, that used to return
    zero incorrectly; with Maxima 5.26.0 one gets
    ``1/2*sqrt(pi)*e^(1/4)``, whereas with 5.29.1, and even more so
    with 5.33.0, the expression is less pleasant, but still has the
    same value.  Unfortunately, the computation takes a very long time
    with the default settings, so we temporarily use the Maxima
    setting ``domain: real``::

        sage: sage.calculus.calculus.maxima('domain: real')
        real
        sage: f = exp(-x) * sinh(sqrt(x))
        sage: t = integrate(f, x, 0, Infinity); t            # long time
        1/4*sqrt(pi)*(erf(1) - 1)*e^(1/4) - 1/4*(sqrt(pi)*(erf(1) - 1) - sqrt(pi) + 2*e^(-1) - 2)*e^(1/4) + 1/4*sqrt(pi)*e^(1/4) - 1/2*e^(1/4) + 1/2*e^(-3/4)
        sage: t.simplify_exp()  # long time
        1/2*sqrt(pi)*e^(1/4)
        sage: sage.calculus.calculus.maxima('domain: complex')
        complex

And the 'long time' is not kidding.

comment:5 Changed 4 years ago by kcrisman

  • Report Upstream changed from Reported upstream. No feedback yet. to Fixed upstream, but not in a stable release.

Apparently fixed again upstream, though still looooong time...

comment:6 Changed 10 months ago by charpent

Sorry, wrong ticket (and I don't know how to delete a comment in Trac...)

Last edited 10 months ago by charpent (previous) (diff)
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