Opened 5 years ago
Last modified 5 years ago
#15789 new defect
Translation from Maxima seems to fail on some big big numbers
Reported by: | kcrisman | Owned by: | |
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Priority: | major | Milestone: | sage-6.4 |
Component: | interfaces | Keywords: | |
Cc: | Merged in: | ||
Authors: | Reviewers: | ||
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description
At 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.
Change History (3)
comment:1 Changed 5 years ago by
comment:2 Changed 5 years ago by
- Milestone changed from sage-6.2 to sage-6.3
comment:3 Changed 5 years ago by
- Milestone changed from sage-6.3 to sage-6.4
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Does this help?
it seems to be ECL's own IEEE negative infinity, which seems to get handled a little strange by maxima.