#15921: work around Maxima fpprintprec bug and other ARM-specific problems
-------------------------------------+-------------------------------------
Reporter: dimpase | Owner:
Type: defect | Status: needs_review
Priority: major | Milestone: sage-6.3
Component: calculus | Resolution:
Keywords: Maxima, | Merged in:
fpprintprec, ARM | Reviewers:
Authors: | Work issues:
Report Upstream: Reported | Commit:
upstream. Developers acknowledge | 079bb9af4f12892268a19f0d218ac96bd72466f4
bug. | Stopgaps:
Branch: |
u/dimpase/arm_fixes_etc |
Dependencies: |
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Comment (by dimpase):
Replying to [comment:17 pbruin]:
> I'm starting to think that we shouldn't try to limit `fpprintprec` after
all, because this will only introduce unnecessary rounding errors. A more
robust solution would be to leave it as 0 and to set `maxfpprintprec`
(which is 16 by default) to 20 or some other sufficiently high value, so
that the output precision is only controlled by the Lisp implementation
(and the platform). At least on x86_64 with ECL, both the length and the
least significant digits are unpredictable: dividing some powers of 10 by
3 gives a result that looks like
> {{{
> 3.333333333333333493e-5
> 3.333333333333333222e-4
> 0.003333333333333333
> 0.03333333333333333
> 0.3333333333333333
> 3.3333333333333335
> 33.333333333333336
> 333.3333333333333
> 3333.3333333333335
> 33333.333333333336
> 333333.3333333333
> 3333333.3333333335
> 3.3333333333333332093e+7
> 3.3333333333333331347e+8
> }}}
how do you get this output?
Is it printed by Sage, or by Maxima, or by ECL?
For me ECL prints something like
{{{
>> (float (/ (expt 10. 3) 3))
333.33334
}}}
even though
{{{
>> (float-precision (float (/ (expt 10. 3) 3)))
24
}}}
--
Ticket URL: <http://trac.sagemath.org/ticket/15921#comment:18>
Sage <http://www.sagemath.org>
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