[R] Better way to find function

[nuvo nuvo]

   >From: "Liaw, Andy"
   >To: "'nuvo nuvo'" ,r-help at stat.math.ethz.ch
   >Subject: RE: [R] Better way to find function
   >Date: Wed, 21 Jan 2004 09:10:06 -0500
   >
   >For #1, could you clarify what you mean by `function', an R function,
   or a

   >regression function?

   I mean to choose a functional form automatically, e.g. 1/(
   a+exp[b+cx]), a+bx, ... [ I saw some of the commercial software can do
   it ]. 
   >For #2, there are several packages on CRAN (and in the R distribution
   >itself) that fit regression splines, if that's what you meant by
   `piecewise
   >regression'.  For logistic regression, you can either use the bs()
   term in

   >glm(), or gam() in the `mgcv' package.

   I don't want to use Spline, because I need the functional form and
   also parameters. Moreover I have 3 independent variables, not only
   one. 

   I want to do only 2 piecewise regression by using the logistic
   function i.e. c/( 1+exp[a+bx]). Then it will be difficult where to put
   the knot and also it may not be continuous at the knot.
   >
   >HTH,
   >Andy
   >
   > > From: nuvo nuvo
   > >
   > > To whom it may concern,
   > >
   > > 1. I would like to know if there is a command in R to choose
   > > a function for
   > > a given dataset. I am facing a difficult question about how
   > > to fit the data
   > > [ please attachment ]
   > >
   > > 2. Are there any function that will allow users to do the
   piecewise
   > > regression?
   > >
   > > If not, is it going to be provide in the new updated version?
   > > What I am
   > > using is the piecewise logistic regression, but it doesn't
   > > have a continuous
   > > function though. I hope that R would have a specific command
   > > to do the
   > > piecewise (non)linear regression.
   > >
   > > I would apprecaite your suggestion.
   > >
   > > Sincerely yours,
   > >
   > > Nhum
   > >
   > > _________________________________________________________________
   > > Rethink your business approach for the new year with the
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   > >
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   > >
   >
   >
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