#15789: Translation from Maxima seems to fail on some big big numbers
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Reporter: kcrisman | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-6.2
Component: interfaces | Keywords:
Merged in: | Authors:
Reviewers: | Report Upstream: N/A
Work issues: | Branch:
Commit: | Dependencies:
Stopgaps: |
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At [http://ask.sagemath.org/question/3499/looong-computation-by-
desolve_rk4 this ask.sagemath question], the following issue came up.
{{{
sage: desolve_rk4(f(t,y), y, ivar=t, ics=[0,-4], end_points=[0,.4])
[[0, -4],
[0.1, -6.44026308551],
[0.2, -18.4360863753],
[0.3, -9638.98851821],
[0.4, -2.29907718472e+44]]
}}}
works, but
{{{
sage: desolve_rk4(f(t,y), y, ivar=t, ics=[0,-4], end_points=[0,.5])
TypeError: unable to make sense of Maxima expression
'[[0,-4],[0.1,-6.440263085506939],[0.2,-18.436086375306434],[.30000000000000004,-9638.988518207414],[0.4,-229907718471530700000000000000000000000000000.],[0.5,-.000000000000000.000000000000000]]'
in Sage
}}}
and indeed `-.000000000000000.000000000000000` makes no sense inside of
Sage. I'm not sure what it's supposed to mean in Maxima, either!
Here is the problem, in Maxima.
{{{
(%i1) rk(6+y-y^2,y,-4,[t,0,.5,.1]);
(%o1) [[0, - 4], [0.1, - 6.440263085506939], [0.2, -
18.436086375306434],
[.30000000000000004, - 9638.988518207414], [0.4, -
2.2990771847153071e+44],
[0.5, - .000000000000000e+4932]]
}}}
I'm not sure exactly what is going on in Sage here, because
{{{
sage: a = maxima('- 2.2990771847153071e+44')
sage: a._sage_()
-2.29907718472e+44
sage: b = maxima(' - .000000000000000e+4932')
sage: b._sage_()
0.0
}}}
so it must be something about how these are translated.
--
Ticket URL: <http://trac.sagemath.org/ticket/15789>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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