#12152: Maxima fails to properly convert some floats to rationals
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Reporter: ddrake | Owner: burcin
Type: defect | Status: new
Priority: major | Milestone:
sage-5.6
Component: calculus | Resolution:
Keywords: maxima keepfloat integration | Work issues:
Report Upstream: Reported upstream. No feedback yet. | Reviewers:
Authors: | Merged in:
Dependencies: | Stopgaps:
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Comment (by kcrisman):
Interestingly, we never considered the following from an old sage-devel
conversation.
{{{
No, it means that you have not noticed the value set for ratepsilon,
which governs the tolerance
for conversion of floats to rationals. It is by default set to
2.0e-8, presumably for "single float"
systems. It should probably be set to something more like 10e-16 for
double float systems.
Ah, that is very helpful. In this case the numerical approximations
do indeed agree up to the output of n(). Perhaps we could potentially
go back to keepfloat:false but with whatever the standard precision in
Sage would equate to - Jason, would that help things with matrices?
}}}
This would probably keep a lot of problems away, especially since, as Nils
says elsewhere, floats and symbolic integrals don't really mix.
Anyway, see also https://sourceforge.net/p/maxima/bugs/2510/#fd1d
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/12152#comment:3>
Sage <http://www.sagemath.org>
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