Re: Same .m file: different results with different versions of Octave

[perseu.as]

Jaroslav Hajek-2 wrote:
> 
> On Sun, Apr 18, 2010 at 8:26 PM, Judd Storrs <address@hidden> wrote:
>> I agree. But I don't think correct results are beyond the scope of
>> octave. So many platforms may be broken in unique ways--and yet I
>> don't think I'm alone with the expectation that octave will work.
> 
> Octave is a system for *numerical* computations. The results of its
> computations are, in general, approximations. The fact that some
> approximations are not accurate enough for your purposes does not
> necessarily mean Octave doesn't work. It works well for me (in this
> case at least).
> 
> Btw, it may be just an issue with the complex division. I see this:
> 
> octave:1> arg = 710*(1+i)
> arg =  710 + 710i
> octave:2> sinh(arg) / cosh(arg)
> ans =  1
> octave:3> tanh(arg)
> ans = NaN
> 
>> When numerical accuracy/correctness matters, use Windows?
>> For example, the bug in glibc's implementation of tanh (the debian bug
>> report leading to the glibc bug report attributes the test code to
>> you, btw) was apparently fixed in 2005. It's not fixed now 2010.
>> Either it wasn't actually fixed or it has now regressed or perhaps
>> we're still waiting for a released version with the fix five years
>> later.
>>
>> What's so special about the C/C++ standard libraries numerics when
>> we've got a high-quality free numerics library? Would anyone be
>> shocked if GSL was a dependency of octave? Is there some problem with
>> GSL that makes its use unacceptable or why we should avoid it?
> 
> Let me reverse your question somewhat: What's so special about GSL
> that makes you think a regression in GSL is much less probable? And
> why can't the same be done for glibc/libstdc++?
> 
> -- 
> RNDr. Jaroslav Hajek, PhD
> computing expert & GNU Octave developer
> Aeronautical Research and Test Institute (VZLU)
> Prague, Czech Republic
> url: www.highegg.matfyz.cz
> 
I see Octave as a tool, not a "toy".

In serious applications, like academic or scientific research,
accuracy on numerical computations are very important
and essential to anyone that use the software.

I would like to see this great software reach
a maturity+accuracy level that I can use it with no doubts.

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