#14976: integration with non symbolic bounds broken
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Reporter: burcin | Owner:
Type: defect | Status: new
Priority: critical | Milestone: sage-5.12
Component: symbolics | Resolution:
Keywords: integration | Merged in:
Authors: | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Dependencies:
Stopgaps: |
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Comment (by nbruin):
Replying to [comment:3 charpent]:
> So ? If this was tre source of the error, it shouldn't happen with
symbolic lower and upper bounds (see my slightly generalized example), but
it does. Furrthermore, declaring the bounds as real allows for completing
the task (bothh from maxima and from sage)...
It's the source of the errors reported in the ticket. The problems
reported in the ticket arise without interaction with maxima.
You're diagnosing a different problem, that integration with certain
''symbolic'' bounds is ''also'' broken. Compare:
{{{
sage: var('x,t,a,b')
(x, t, a, b)
sage: function('f')
f
sage: function('g')
g
sage: integrate(f(x),x,a,b)
integrate(f(x), x, a, b)
sage: integrate(f(x),x,sin(t),b)
integrate(f(x), x, sin(t), b)
sage: integrate(f(x),x,sin(1+i*t),b)
RuntimeError: ECL says: Error executing code in Maxima: defint: lower
limit of integration must be real; found sin(%i*t+1)
sage: integrate(f(x),x,g(t),b)
RuntimeError: ECL says: Error executing code in Maxima: defint: lower
limit of integration must be real; found g(t)
}}}
Indeed, for definite integrals, maxima seems to want to know if the
integration bounds are real.
However, Maxima seems to assume quite happily by itself that `a,b,sin(t)`
are real, but doesn't think `sin(1+i*t)` is real and for some reason
refuses to assume anything about `g(t)`.
Your workaround is interesting in that it shows that maxima's "assume"
facility can be of some help to nudge maxima into the desired direction.
It seems to me the problem you're diagnosing is best addressed by working
mainly on maxima. As far as I've seen, sage is offering reasonable input
to maxima.
--
Ticket URL: <http://trac.sagemath.org/ticket/14976#comment:4>
Sage <http://www.sagemath.org>
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