[R] bivariate function in gam model

[Chong Gu]

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   Date: Thu, 17 May 2001 09:54:03 -0500
   From: Stephen Ellner <spe2 at cornell.edu>
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   I don't think this actually is a GAM model
    >       logit(p) = a + f(x1) + f(x2) + f(x1,x2)
   unless you mean f(x1*x2) or something like that instead of a
   completely general f(x1,x2); in particular it is equivalent to
   (*)     logit(p) = f(x1,x2)
   with f(x1,x2) a surface. I'm not aware of anything for R that
   includes nonparametric bivariate logistic regression, unless
   maybe one of the fitting options in nnet would be appropriate for
   your data? tps in funfits can fit a bivariate surface but the only
   fitting option is least squares.

    >
    > R-users --
    >
    > I would be interested in tools in R to fit the following gam model:
    >
    > logit(p) = a + f(x1) + f(x2) + f(x1,x2),
    >
    > where f(x1,x2) defines a surface.
    >
    > I have looked into the mgcv library, but it seems only to fit models of
    > the form:
    >
    > logit(p) = a + f(x1) + f(x2)
    >
    > Any ideas?
    >
    > Cheers,
    > Dan
    >



   -------------------------------------------------------
   Stephen P. Ellner (spe2 at cornell.edu)
   Dept. of Ecology and Evolutionary Biology
   Corson Hall, Cornell University, Ithaca NY 14853-2701
   Phone (607) 254-4221    FAX (607) 255-8088


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You may want to check out the gss package.
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