#11238 closed defect (fixed)
failing calculation of a symbolic integral
Reported by: | casamayou | Owned by: | burcin |
---|---|---|---|
Priority: | major | Milestone: | sage-5.0 |
Component: | calculus | Keywords: | integrate |
Cc: | zimmerma, kcrisman | Merged in: | sage-5.0.beta12 |
Authors: | Michael Orlitzky | Reviewers: | Karl-Dieter Crisman |
Report Upstream: | Fixed upstream, in a later stable release. | Work issues: | |
Branch: | Commit: | ||
Dependencies: | #11445 | Stopgaps: |
Description
With a symbolic calculation, Sage returns 0 for the integral integrate(exp(-x)*sinh(sqrt(x)), x, 0, oo) instead of exp(1/4) * sqrt(pi) / 2
sage: integrate(exp(-x)*sinh(sqrt(x)), x, 0, oo) 0 sage: integral_numerical(exp(-x)*sinh(sqrt(x)), 0, oo) (1.1379378972322944, 3.1822014179283542e-07) sage: (exp(1/4) * sqrt(pi) / 2).n() 1.13793789723437 sage: plot(exp(-t)*sinh(sqrt(t)), t, 0, 10)
Attachments (1)
Change History (11)
comment:1 Changed 10 years ago by
- Report Upstream changed from N/A to Reported upstream. Little or no feedback.
comment:2 Changed 9 years ago by
- Report Upstream changed from Reported upstream. Little or no feedback. to Fixed upstream, in a later stable release.
This is NOT fixed in 5.24, so we can't yet do it, but it is now fixed in Maxima 5.26.
(%i2) display2d:false; (%o2) false (%i3) integrate(exp(-x)*sinh(sqrt(x)),x,0,inf); (%o3) %e^(1/4)*sqrt(%pi)/2
comment:3 Changed 9 years ago by
- Cc kcrisman added
- Status changed from new to needs_review
Here's another one I found fixed by the Maxima upgrade. The patch will apply cleanly on top of #11445. I put the test in the same place as that one, but I could of course copy/paste them out together.
comment:4 Changed 9 years ago by
- Dependencies set to #11445
- Reviewers set to Karl-Dieter Crisman
- Status changed from needs_review to positive_review
Looks good. No worries about the cut/paste. However, let's try to put others in the symbolic integration ones... Maybe we should even separate some of them out into one of our "tests" files in calculus/ or something.
comment:5 Changed 9 years ago by
- Merged in set to sage-5.0.beta12
- Resolution set to fixed
- Status changed from positive_review to closed
comment:6 Changed 9 years ago by
This seems to be back with maxima-5.27.0, but only with domain: complex;
Maxima 5.27.0 http://maxima.sourceforge.net using Lisp ECL 12.2.1 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)*sqrt(%pi)/2 (%i3) domain:complex; (%o3) complex (%i4) integrate(exp(-x)*sinh(sqrt(x)),x,0,inf); (%o4) 0
Reported upstream at https://sourceforge.net/tracker/?func=detail&aid=3529144&group_id=4933&atid=104933.
comment:7 Changed 9 years ago by
thank you Michael, the new doctest will bump when/if we upgrade to Maxima 5.27.
Paul
comment:8 Changed 9 years ago by
This is fixed upstream, again. It should make it into maxima-5.28.
comment:9 Changed 7 years ago by
I won't reopen this one, but it is definitely still there - to the point that I don't see how we can be passing doctests!
(%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); <hangs>
See #17469. Weirdly, the doctest does pass, but we had to change things at some point, which is a regression on Maxima's part:
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
comment:10 Changed 7 years ago by
with 6.0 both work but take a long time:
sage: sage.calculus.calculus.maxima('domain: real') real sage: integrate(exp(-x)*sinh(sqrt(x)), x, 0, oo) 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: sage.calculus.calculus.maxima('domain: complex') complex sage: integrate(exp(-x)*sinh(sqrt(x)), x, 0, oo) 1/4*(sqrt(pi)*(erf(1) - 1) + sqrt(pi) + 2*e^(-1) - 2)*e^(1/4) - 1/4*(sqrt(pi)*(erf(1) - 1) - sqrt(pi) + 2*e^(-1) - 2)*e^(1/4)
Paul
This is also present in the latest Maxima. This is now reported at this Maxima bug artifact.