Re: range of fitted variable

For sophisticated data analysis, please consider use other tools.
Python +SciPy+NumPy+Matplotlib on Jupyter-Lab, GNU Octave, or Scilab.

gnuplot is a basically plotting tool and do not expect to use it for complicated cases.

Tatsuro



----- Original Message -----
> From: Patrick Dupre 
> To: tmacchant3
> Cc: 
> Date: 2019/6/30, Sun 16:52
> Subject: Re: [Gnuplot-info] range of fitted variable
> 
> Yes, It is interesting. Thanks.
> Finally, used the conditional ()?{}:{} to restrict the parameter range.
> 
> ===========================================================================
> Patrick DUPRÉ                                 | | email: [email protected]
> Laboratoire interdisciplinaire Carnot de Bourgogne
> 9 Avenue Alain Savary, BP 47870, 21078 DIJON Cedex FRANCE
> Tel: +33 (0)380395988
> ===========================================================================
> 
> 
>>  Sent: Sunday, June 30, 2019 at 1:44 AM
>>  From: "Tatsuro MATSUOKA" <[email protected]>
>>  To: "Patrick Dupre" <[email protected]>
>>  Cc: [email protected]
>>  Subject: Re: [Gnuplot-info] range of fitted variable
>> 
>>  Tricks are given in the below
>> 
>>  http://gnuplot-tricks.blogspot.com/2009/12/restricting-fit-parameters.html 
>> 
>> 
>> 
>>  Tatsuro
>> 
>> 
>>  ----- Original Message -----
>>  > From: Tatsuro MATSUOKA
>>  > To: Patrick Dupre 
>>  > Cc: gnuplot-info> Date: 2019/6/30, S
>>  un 08:17
>>  > Subject: Re: [Gnuplot-info] range of fitted variable
>>  > 
>>  >>  Even with Marquardt-Levenberg method, you can constrain 
> parameters.
>>  > 
>>  > OK. This is just my ignorance.
>>  > Anyway, gnuplot fit uses unconstrained least square method.
>>  > 
>>  >>  Anyway, you can always does it in the function, and put the 
> constrains here
>>  >>  since conditional statement are accepted. 
>>  > 
>>  > help fit says
>>  > gnuplot> help fit
>>  >  The `fit` command fits a user-supplied real-valued expression to a 
> set of
>>  >  data points, using the nonlinear least-squares Marquardt-Levenberg
>>  >  algorithm. There can be up to 12 independent variables, there is 
> always 1
>>  >  dependent variable, and any number of parameters can be fitted.
>>  >  Optionally, error estimates can be input for weighting the data 
> points.
>>  > 
>>  >  The basic use of `fit` is best explained by a simple example:
>>  > 
>>  >        f(x) = a + b*x + c*x**2
>>  >        fit f(x) 'measured.dat' using 1:2 via a,b,c
>>  >        plot 'measured.dat' u 1:2, f(x)
>>  > 
>>  >  Syntax:
>>  >        fit {<ranges>} <expression>
>>  >            '<datafile>' {datafile-modifiers}
>>  >            {{unitweights} | {y|xy|z}error | errors 
>>  > <var1>{,<var2>,...}}
>>  >            via '<parameter file>' | 
>>  > <var1>{,<var2>,...}
>>  > 
>>  > 
>>  > ----- Original Message -----
>>  > 
>>  >>  From: Patrick Dupre 
>>  >>  To: Tatsuro MATSUOKA 
>>  >>  Cc: gnuplot 
>>  >>  Date: 2019/6/30, Sun 07:18
>>  >>  Subject: Re: [Gnuplot-info] range of fitted variable
>>  >> 
>>  >>  Hello,
>>  >> 
>>  >>  I am not sure that it is a helfull response.
>>  >>  Even with Marquardt-Levenberg method, you can constrain 
> parameters.
>>  >>  Anyway, you can always does it in the function, and put the 
> constrains here
>>  >>  since conditional statement are accepted.
>>  >> 
>>  >>  Regards.
>>  >> 
>>  >>>   Subject: Re: [Gnuplot-info] range of fitted variable
>>  >>> 
>>  >>>   --- pdupre
>>  >>>   > Hello,
>>  >>>   >
>>  >>>   > Can I set a range to the fitted variable ?
>>  >>>   > An option could be to set a if (condition) in the 
> fitting 
>>  > function. Is 
>>  >>  it possible?
>>  >>>   >
>>  >>>   > Thanks
>>  >>>   >
>>  >>> 
>>  >>>   fit of gnuplot use Marquardt-Levenberg method.
>>  >>>   Marquardt-Levenberg method is a uncostrained method. You 
> cannot set 
>>  > bounds 
>>  >>  of parameters.
>>  >>> 
>>  >>>   Tatsuro
>>  >>> 
>>  >>> 
>>  >> 
>>  > 
>> 
>> 
> 



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