#11238: failing calculation of a symbolic integral
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Reporter: casamayou | Owner: burcin
Type: defect | Status: closed
Priority: major | Milestone: sage-5.0
Component: calculus | Resolution: fixed
Keywords: integrate | Merged in:
Authors: Michael Orlitzky | sage-5.0.beta12
Report Upstream: Fixed upstream, in a later | Reviewers: Karl-
stable release. | Dieter Crisman
Branch: | Work issues:
Dependencies: #11445 | Commit:
| Stopgaps:
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Comment (by kcrisman):
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
}}}
--
Ticket URL: <http://trac.sagemath.org/ticket/11238#comment:9>
Sage <http://www.sagemath.org>
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