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

[Hans W Borchers]

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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