Message-ID: <2213A07C-E9A8-4EA2-B62E-2027A2E7A9D6@comcast.net>
Date: 2011-04-24T22:25:10Z
From: David Winsemius
Subject: Multi-dimensional non-linear fitting - advice on best method?
In-Reply-To: <20110424003813.GB9726@d-and-j.net>
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