[R] R nls results different from those of Excel ??

[Jeff Newmiller]

I use Excel regularly, and do not consider this a "slam"... it is a fact. I am aware of Solver, but the query was about trend lines generated by Excel. In general it is possible to do arbitrarily complex computations with a four function calculator, but we don't describe that as something the calculator does. Setting up a Solver sheet to obtain trend coefficients is not a typical way to obtain them in Excel... that would be the user's doing, not Excel's. 
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Sent from my phone. Please excuse my brevity.

Hans W Borchers <hwborchers at googlemail.com> wrote:

>Jeff Newmiller <jdnewmil <at> dcn.davis.ca.us> writes:
>> 
>> Excel definitely does not use nonlinear least squares fitting for
>power
>> curve fitting. It uses linear LS fitting of the logs of x and y.
>There
>> should be no surprise in the OP's observation.
>
>May I be allowed to say that the general comments on MS Excel may be
>alright,
>in this special case they are not.  The Excel Solver -- which is made
>by an
>external company, not MS -- has a good reputation for being fast and
>accurate.
>And it indeed solves least-squares and nonlinear problems better than
>some of
>the solvers available in R.
>There is a professional version of this solver, not available from
>Microsoft,
>that could be called excellent. We, and this includes me, should not be
>too 
>arrogant towards the outside, non-R world, the 'barbarians' as the
>ancient 
>Greeks called it.
>
>Hans Werner
>
>>
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>> Jeff Newmiller                        The     .....       .....  Go
>Live...
>> DCN:<jdnewmil <at> dcn.davis.ca.us>   Basics: ##.#.       ##.#.  Live
>Go...
>>                                       Live:   OO#.. Dead: OO#.. 
>Playing
>> Research Engineer (Solar/Batteries            O.O#.       #.O#.  with
>> /Software/Embedded Controllers)               .OO#.       .OO#. 
>rocks...1k
>>
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>
>> Sent from my phone. Please excuse my brevity.
>
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