#14821: Weird error in exponential integral
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Reporter: ppurka | Owner: burcin
Type: defect | Status: new
Priority: major | Milestone: sage-5.12
Component: calculus | Resolution:
Keywords: | Work issues:
Report Upstream: N/A | Reviewers:
Authors: | Merged in:
Dependencies: | Stopgaps:
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Changes (by kcrisman):
* cc: nbruin (added)
Comment:
Wait, I'm confused. What does the value of the derivative have to do with
`keepfloat` and this behavior?
{{{
sage: H = exp(-.00001*x)
sage: H.integral(x,0,1)
<same error>
sage: plot(H,(x,0,1),ymin=0)
<essentially constant plot>
}}}
The reason why Nils and others consider this to be close to user error is
that it's not clear what a non-numerical integral of an integral with
floats in it should mean. The indefinite integral would be inaccurate by
definition. Or am I misrepresenting something, Nils?
One possible workaround I see is that we could catch this error and ask
the user whether they wanted a numerical integral, or even return a
numerical integral. We haven't seen this in circumstances without
exponentials of floats.
Another thing to note is that it's the ''endpoints'' being floats which
caused `keepfloat` to be necessary. We could investigate whether we want
to only use `keepfloat:true` in those situations.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/14821#comment:4>
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