Re: [R] Multi-dimensional non-linear fitting - advice on best method?

From: David Winsemius <>
Date: Sun, 24 Apr 2011 18:25:10 -0400

On Apr 23, 2011, at 8:38 PM, Julian Gilbey wrote:

> Hello!
> I have a set of data of the form (x, y1, y2) where x is the
> independent variable and (y1, y2) is the response pair. The model is
> some messy non-linear function:
> (y1, y2) = f(x; param1, param2, ..., paramk) + (y1error, y2error)
> where the parameters param1, ..., paramk are to be estimated, and I'll
> assume the errors to be normal for sake of simplicity.
> If there were only one response per input, I would use the nls()
> function, but what can I do in this case?

I wonder it would be sensible or at least informative to consider solving for the "inverse case". i.e. solve for:

x = f(y1, y2)

David Winsemius, MD
West Hartford, CT

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Received on Sun 24 Apr 2011 - 22:29:20 GMT

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