Am 05.05.2011 21:32, schrieb Ethan A Merritt:
> On Thursday, May 05, 2011 12:01:53 am Bastian Märkisch wrote:
>>> I may be missing something, but why not just report both
>>> absolute and relative errors? The user is free to pick whichever
>>> is relevant to the particular case at hand. No extra options needed.
>>>
>>> Ethan
>>
>> I think you just proved that the name may be misleading ;). This is
>> about the interpretation of data errors (input), and the resulting
>> scaling with FIT_STDFIT of reported variable errors (output). This is
>> not about reporting relative errors as in a_err/a.
>
> From Thomas Mattison's mail that you linked to
> http://thread.gmane.org/gmane.comp.graphics.gnuplot.devel/3737/focus=3740
>
> Gnuplot already does the right calculation internally, it just doesn't
> report it. It reports only a non-standard, fluctuation-sensitive error
> (although I will grant that it is possible in most cases to recover the
> standard error from the fit log by some simple hand calculations).
>
> I took this to mean that the issue is ultimately one of reporting.
> Right now we report errors calculated under one set of assumption;
> he is asking that we also report errors calculated under a different
> set of assumption. My question is why not just report both?
> The current values become a set of "FIT_*_SCALED_*" output parameters
> and the new ones become a parallel set of "FIT_*_UNSCALED_*" parameters.
>
> But I admit to saying this without having thought deeply about the
> underlying issue. Just ignore me if I'm not making sense :-)
>
To me, adding a user option still seems to be a good solution, since
there's also the issue of error variables ('set fit errorvariables'). I
am not sure gnuplot already had that feature back then. Imho, data
errors are either one or the other.
>> Not only is scaling the errors wrong in certain cases, but these error
>> values are also saved to variables for further processing, e.g. in
>> labels. Since, the user should be able to select. With `set fit abs`
>> gnuplot reports the same errors as e.g. CERN Minuit.
>>
>> Any other ideas about the names? weights|errors? scaling|noscaling?
>> weights|real?
>>
>> Bastian
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