Displaying 20 results from an estimated 10000 matches similar to: "Extracting the results of a gam smooth"
2005 Oct 12
1
step.gam and number of tested smooth functions
Hi,
I'm working with step.gam in gam package. I'm interested both in spline and
lowess functions and when I define all the models that I'm interested in I get
something like that:
> gam.object.ALC<-gam(X143S~ALC,data=dane,family=binomial)
>
2005 Sep 23
1
Smooth terms significance in GAM models
hi,
i'm using gam() function from package mgcv with default option (edf
estimated by GCV).
>G=gam(y ~ s(x0, k = 5) + s(x1) + s(x2, k = 3))
>SG=summary(G)
Formula:
y ~ +s(x0, k = 5) + s(x1) + s(x2, k = 3)
Parametric coefficients:
Estimate std. err. t ratio Pr(>|t|)
(Intercept) 3.462e+07 1.965e+05 176.2 < 2.22e-16
Approximate significance of smooth
2013 Mar 21
1
[mgcv][gam] Odd error: Error in PredictMat(object$smooth[[k]], data) : , `by' variable must be same dimension as smooth arguments
Dear List,
I'm getting an error in mgcv, and I can't figure out where it comes
from. The setup is the following: I've got a fitted GAM object called
"MI", and a vector of "prediction data" (with default values for
predictors). I feed this into predict.gam(object, newdata = whatever)
via the following function:
makepred = function(varstochange,val){
for
2005 Nov 23
1
1st derivative {mgcv} gam smooth
Dear R-hep,
I'm trying to get the first derivative of a smooth from a gam
model like:
model<-gam(y~s(x,bs="cr", k=5)+z) and need the derivative: ds(x)/dx. Since
coef(model) give me all the parameters, including the parameters of the
basis, I just need the 1st derivative of the basis s(x).1, s(x).2, s(x).3,
s(x).4. If the basis were generated with the function
2007 Apr 16
1
Does the smooth terms in GAM have a functional form?
Hi, all,
Does anyone know how to get the functional form of the smooth terms in GAM? eg. I fit y=a+b*s(x) where s is the smooth function.
After fitting this model with GAM in R, I want to know the form of the s(x). Any suggestion is appreciated.
Thanks,
Jin
---------------------------------
Ahhh...imagining that irresistible "new car" smell?
2003 Jul 24
1
scatterplot smoothing using gam
All:
I am trying to use gam in a scatterplot smoothing problem.
The data being smoothed have greater 1000 observation and have
multiple "humps". I can smooth the data fine using a function
something like:
out <- ksmooth(x,y,"normal",bandwidth=0.25)
plot(x,out$y,type="l")
The problem is when I try to fit the same data using gam
out <-
2009 May 05
1
A question about using “by” in GAM model fitting of interaction between smooth terms and factor
I am a little bit confusing about the following help message on how to fit a
GAM model with interaction between factor and smooth terms from
http://rss.acs.unt.edu/Rdoc/library/mgcv/html/gam.models.html:
?Sometimes models of the form:
E(y)=b0+f(x)z
need to be estimated (where f is a smooth function, as usual.) The
appropriate formula is:
y~z+s(x,by=z)
- the by argument ensures that the smooth
2008 Jan 03
1
GLM results different from GAM results without smoothing terms
Hi, I am fitting two models, a generalized linear model and a generalized
additive model, to the same data. The R-Help tells that "A generalized
additive model (GAM) is a generalized linear model (GLM) in which the linear
predictor is given by a user specified sum of smooth functions of the
covariates plus a conventional parametric component of the linear
predictor." I am fitting the GAM
2013 Jul 23
1
Help with using unpenalised te smooth in negative binomial mgcv gam
Hi,
I have been trying to fit an un-penalised gam in mgcv (in order to get more
reliable p-values for hypothesis testing), but I am struggling to get the
model to fit sucessfully when I add in a te() interaction. The model I am
trying to fit is:
gam(count~ s(x1, bs = "ts", k = 4, fx = TRUE) +
s(x2, bs = "ts", k = 4, fx = TRUE) +
te(x2, x3, bs =
2009 May 05
2
smoothing spline in package gam
dear all,
i have a little question, but it make me torment long time
hope you can help me and give some advices , thanks
i use smoothing spline in package gam
the model
> m1=gam(y~ost+wst+park10+sch50+comm+build+suite+y05+y06+y07+y99+y98+s(builarea)+s(age)+s(fl)+s(totfl)+s(cbd)+s(redl))
and summary(m1) can show the "s"(smoothing) variables' Signif. codes.
2003 Nov 22
0
: how to plot smooth function estimate from gam (mgcv package) in other program
Hi all,
I would like to export the smooth function estimate I got from gam to plot
it in another graphics software. In S-plus I use the function preplot() for
that, but it seems not to work in R.
Has somebody an idea how to solve that?
Thanks
Stephanie
********************************
Stephanie von Klot
Institut f?r Epidemiologie
GSF - Forschungszentrum
f?r Umwelt und Gesundheit
Ingolst?dter
2012 May 23
0
gam (mgcv) vs. multiple regression breakpoint analysis: inconsistencies?
Dear useRs,
I have a question with respect to fitting a non-linearity using gam
(mgcv package, version 1.7-16).
In a study I'm currently conducting, I'd like to find out if there is
a breakpoint after which the effect of Age of Acquisition (AOA) of the
second language changes. I.e. if the slope of AOA before the
breakpoint (at a certain AOA) is different from the slope past the
2011 Mar 07
0
Conflict between gam::gam and mgcv::gam
I am trying to compare and contrast the smoothing in the {mgcv} version
of gam vs. the {gam} version of gam but I get a strange side effects
when I try to alternate calls to these routines, even though I detach
and unload namespaces.
Specifically when I start up R the following code runs successfully
until the last line i.e. plot(g4,se=TRUE) when I get "Error in
dim(data) <- dim :
2011 Mar 11
0
variance explained by each term in a GAM
Picking up an ancient thread (from Oct 2007), I have a somewhat more complex
problem than given in Simon Wood's example below. My full model has more than
two smooths as well as factor variables as in this simplified example:
b <- gam(y~fv1+s(x1)+s(x2)+s(x3))
Judging from Simon's example, my guess is to fit reduced models to get
components of deviance as follows:
b1 <-
2004 Aug 06
2
gam --- a new contributed package
I have contributed a "gam" library to CRAN,
which implements "Generalized Additive Models".
This implementation follows closely the description in
the GAM chapter 7 of the "white" book "Statistical Models in S"
(Chambers & Hastie (eds), 1992, Wadsworth), as well as the philosophy
in "Generalized Additive Models" (Hastie & Tibshirani 1990,
2004 Aug 06
2
gam --- a new contributed package
I have contributed a "gam" library to CRAN,
which implements "Generalized Additive Models".
This implementation follows closely the description in
the GAM chapter 7 of the "white" book "Statistical Models in S"
(Chambers & Hastie (eds), 1992, Wadsworth), as well as the philosophy
in "Generalized Additive Models" (Hastie & Tibshirani 1990,
2018 Jan 17
1
mgcv::gam is it possible to have a 'simple' product of 1-d smooths?
I am trying to test out several mgcv::gam models in a scalar-on-function regression analysis.
The following is the 'hierarchy' of models I would like to test:
(1) Y_i = a + integral[ X_i(t)*Beta(t) dt ]
(2) Y_i = a + integral[ F{X_i(t)}*Beta(t) dt ]
(3) Y_i = a + integral[ F{X_i(t),t} dt ]
equivalents for discrete data might be:
1) Y_i = a + sum_t[ L_t * X_it * Beta_t ]
(2) Y_i
2010 Dec 08
1
I want to get smoothed splines by using the class gam
Hi all,
I try to interpolate a data set in the form:
time Erg
0.000000 48.650000
1.500000 56.080000
3.000000 38.330000
4.500000 49.650000
6.000000 61.390000
7.500000 51.250000
9.000000 50.450000
10.500000 55.110000
12.000000 61.120000
18.000000 61.260000
24.000000 62.670000
36.000000 63.670000
48.000000 74.880000
I want to get smoothed splines by using the class gam
The first way I tried , was
2007 Jun 22
1
two basic question regarding model selection in GAM
Qusetion #1
*********
Model selection in GAM can be done by using:
1. step.gam {gam} : A directional stepwise search
2. gam {mgcv} : Smoothness estimation using GCV or UBRE/AIC criterion
Suppose my model starts with a additive model (linear part + spline part).
Using gam() {mgcv} i got estimated degrees of freedom(edf) for the smoothing
splines. Now I want to use the functional form of my model
2008 Nov 15
1
GAMs and GAMMS with correlated acoustic data
Greetings
This is a long email.
I'm struggling with a data set comprising 2,278 hydroacoustic estimates of
fish biomass density made along line transects in two lakes (lakes
Michigan and Huron, three years in each lake). The data represent
lakewide surveys in each year and each data point represents the estimate
for a horizontal interval 1 km in length.
I'm interested in comparing