Re: Omitting values for Leasqr

[Freddy López]

Hello AG,

This situation has not a direct solution. 

When you remove some data, you are changing the data's structure and it will be reflected in your fitting. In some situations (perhaps when prediction it is not neccesary) just the curve is enough. I don't know if this is your case. 

On other hand, I'm nearly sure that substitute the value by Na or NaN is not a good option (are those data removed?). 

A possible solution to reach convergence, is to use a bootstrapped sample. This site can be useful http://www.maths.lth.se/matstat/stixbox/Contents.html.

Cheers.

On Tue, Mar 8, 2011 at 20:21, aegreen <address@hidden> wrote:

I am trying to fit an exponential curve to data using the leasqr() function.
I can fit the data no problem. However my data has a lot of noise and our
policy is to remove data points that are outside of 2 standard deviations of
the mean of the residuals from an exponential curve that is initially fit to
the data. I have tried replacing the values with NA or NaN and it exits with
an error of "CONVERGENCE NOT ACHIEVED!" my temporary solution is to replace
the value with a local mean, however ideally I would like to omit the value
without changing the data.

Any help would be appreciated.

AG

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