#13427: Numerical noise causing sage/numerical/optimize.py to fail on SPARC
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Reporter: drkirkby | Owner: jason, jkantor
Type: defect | Status: new
Priority: major | Milestone: sage-5.4
Component: numerical | Resolution:
Keywords: solaris, glpk | Work issues:
Report Upstream: N/A | Reviewers:
Authors: | Merged in:
Dependencies: | Stopgaps:
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Description changed by drkirkby:
Old description:
> Using:
>
> * Sage 5.3.rc0 built with gcc 4.5.0 (i.e. NOT the gcc in Sage)
> * Solaris 10 3/05 s10_74L2a SPARC
> * Sun Blade 2000 with two 1200 MHz UltraSPARC III CPUs
>
> {{{
> File "/export/home/drkirkby/sage-5.3.rc0/devel/sage-
> main/sage/numerical/optimize.py", line 135:
>
> sage: find_local_maximum(fast_float(8*e^ (-x)*sin(x) - 1, x), 0, 8)^
>
> Expected:
>
> (1.579175535558..., 0.78539817...)
>
> Got:
>
> (1.5791755355586758, 0.78539816111340355)
> }}}
> Actually, the result returned on SPARC is more accurate in this instance,
> as according to Mathematica 7 at least,
>
> {{{
> In[3]:= FindMaximum[8 E^(-x) Sin[x] -1,{x,0,8},WorkingPrecision->50]
>
> Out[3]= {1.5791755355586755940189354764810356787023224274029,
>
> > {x -> 0.78539816339744830961566077712689095303902649201882}}
>
> In[4]:=
> }}}
> So on SPARC, the relative error is 2.91x10^-9^ and the absolute error of
> -2.28x10^-9^ So the test needs changing to '0.7853981...' rather than
> '0.78539817...'
>
> I'll attach a patch later.
>
> Dave
New description:
Using:
* Sage 5.3.rc0 built with gcc 4.5.0 (i.e. NOT the gcc in Sage)
* Solaris 10 3/05 s10_74L2a SPARC
* Sun Blade 2000 with two 1200 MHz UltraSPARC III CPUs
{{{
File "/export/home/drkirkby/sage-5.3.rc0/devel/sage-
main/sage/numerical/optimize.py", line 135:
sage: find_local_maximum(fast_float(8*e^ (-x)*sin(x) - 1, x), 0, 8)^
Expected:
(1.579175535558..., 0.78539817...)
Got:
(1.5791755355586758, 0.78539816111340355)
}}}
Actually, the result returned on SPARC is more accurate in this instance,
as according to Mathematica 7 at least,
{{{
In[3]:= FindMaximum[8 E^(-x) Sin[x] -1,{x,0,8},WorkingPrecision->50]
Out[3]= {1.5791755355586755940189354764810356787023224274029,
> {x -> 0.78539816339744830961566077712689095303902649201882}}
In[4]:=
}}}
So on SPARC, the relative error is -2.91x10^-9^ and the absolute error of
-2.28x10^-9^ So the test needs changing to '0.7853981...' rather than
'0.78539817...'
I'll attach a patch later.
Dave
--
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/13427#comment:1>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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