RE: nonlin_min function

[steph]

-----Original Message-----
From: Kai Torben Ohlhus <address@hidden> 
Sent: Thursday, April 23, 2020 09:53
To: Steph Bredenhann <address@hidden>
Cc: address@hidden
Subject: Re: nonlin_min function

On 4/20/20 6:28 PM, Steph Bredenhann wrote:
> Dear Kai
> 
> In the mean time I have read the manuals again and again and searched 
> Google and I have made the suggested change to MaxFunEvals already, 
> have now increased to 4000 as you suggest, see the options as I have it now.
> 
> GPL_options =
> 
>   scalar structure containing the fields:
> 
>     AutoScaling = off
>     ComplexEqn = off
>     FunValCheck = off
>     FinDiffType = forward
>     Jacobian = off
>     MaxFunEvals =  4000
>     MaxIter =  1000
>     OutputFcn = [](0x0)
>     Updating = off
>     TolFun =  0.0000000010000
>     TolX =  0.0000000010000
>     TypicalX = [](0x0)
> 
> The outcome has now changed to:
> 
> fsolve outcome: GPL_info = 3:  improvement in objective function less 
> than specified
> 
> As you can see I have made TolFun and TolX very small.
> 
> I have also changed my FUN to have a zero RHS as per the manual.
> 
> It seems to me that the model I am investigating just don’t have a 
> solution with this search algorithm.
> 
> Thanks for your assistance, it is much appreciated.
> 
> --
> */Steph /*
> 


Dear Steph,

Can you attach the latest version of your m-files for debugging?

Thanks,
Kai

Dear Kai

m-files attached as requested.

I must just mention that, as the problem is intrinsically a curve fitting 
problem I have also tried lsqcurvefit function with no improvement, as with 
fsolve my "guess" must be very close to the real solution (which I have from 
Excel) and then only 3-5 iterations are completed.

Looking forward to your feedback

Steph

fn_GPL_model.m
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call_script.m
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fn_BBR_GPL.m
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