Displaying 20 results from an estimated 2000 matches similar to: "spline with multiple predictor vars?"
2003 Apr 21
3
significant terms in spline model using GAM
Hi.. I'm using gam() to fit a spline model for a data set that has two predictor
variables (say A and B). The results indicate that the higher order interaction
terms are significant. The R^2 jumps from .5 to .9 when I change the maximum
order for the interaction from 10 to 15 (i.e. (AB)^10 to (AB)^15). Is there any
way of finding out which of the terms in the model are really
2003 Nov 19
2
Difference in ANOVA results - R vs. JMP/Minitab
Hi,
I ran a small data set from a factorial experiment through R, Minitab
and JMP... the result from R is significantly different from what
Minitab or JMP give... The data set is at the following link:
http://www.personal.psu.edu/nug107/Uploads/2x3_16repsANOVA.txt
The first 5 columns are the factors and the next three are responses.
In particular, for the response beta11MSE, two of the
2000 Jul 28
4
gremlin in rep()
the following occurred inadvertently and brought R-1.1.0 down
rep(1:3, c(4,2,-6))
Segmentation Fault (core dumped)
platform i686-pc-linux-gnu
arch i686
os linux-gnu
system i686, linux-gnu
status
major 1
minor 1.0
year 2000
month June
day 15
language R
2003 Nov 25
1
Y axis scale in plot.gam
Hi,
Is there any way to change the y axis range of values in a plot.gam()? I
need that two different GAM plots to be of the same scale.
Also, it is possible to change the labels?
I tried with "ylab" and "ylim" and did not work
Thanks in advance
Ricardo Lopes
Ricardo Lopes
.............................................
Instituto do Mar
Departamento de Zoologia
2003 Oct 31
1
constrained nonlinear optimisation in R?
Hello. I have searched the archives but have not found anything. I
need to solve a constrained optimisation problem for a nonlinear
function (“maximum entropy formalism”). Specifically,
Optimise: -1*SUM(p_ilog(p_i)) for a vector p_i of probabilities,
conditional on a series of constraints of the form:
SUM(T_i*p_i)=k_i for given values of T_i and k_i (these are
constraints on
2003 Jun 03
1
S+ style implementation of GAM for R?
Hi,
I've got the R library "mgcv" for GAM written by Simon Wood which works well
in many instances. However, over the years I
got attached to the S+ implementation of GAM which allows loess smoothing in
more than 1 dimension as well as spline smoothing.
Has anyone ported the S+ GAM library to R?
Regards,
Doug Beare.
Fisheries Research Services,
Marine Laboratory,
Victoria Road,
2003 Jun 05
1
partial residuals in plot.gam()
All,
Sorry for bombarding you with GAM related questions, but...
I know a partial residual option in plot.gam() is on Simon Wood's todo
list, but since I'm in the midst of a project and not yet having acquired
sufficient R knowledge to code something usable myself I'll have to put my
trust in you. Anybody got some code lying around for doing this? Or if
someone can supply me with
2003 Jul 14
1
gam and step
hello,
I am looking for a step() function for GAM's.
In the book Statistical Computing by Crawley and a removal of predictors has
been done "by hand"
model <- gam(y ~s(x1) +s(x2) + s(x3))
summary(model)
model2 <- gam(y ~s(x2) + s(x3)) # removal of the unsignificant variable
#then comparing these two models if an significant increase occurs.
anova(model, model2,
2003 Sep 26
1
least squares regression using (inequality) restrictions
Dear R Users,
I would like to make a lesast squares regression similar to that what is
done by the command "lm". But additionally, I would like to impose some
restrictions:
1) The sum of all regression coefficients should be equal to 1.
2) Each coefficient should assume a value between 0 and 1. (inequality
restrictions)
Which command is the best to use in order to solve this problem
2004 Mar 12
1
GCV UBRE score in GAM models
hello to everybody:
I would to know with ranges of GCV or UBRE values can be considered as
adequate to consider a GAM as correct
Thanks in advance
--
David Nogu?s Bravo
Functional Ecology and Biodiversity Department
Pyrenean Institute of Ecology
Spanish Research Council
Av. Monta?ana 1005
Zaragoza - CP 50059
976716030 - 976716019 (fax)
2004 Jun 16
2
gam
hi,
i'm working with mgcv packages and specially gam. My exemple is:
>test<-gam(B~s(pred1)+s(pred2))
>plot(test,pages=1)
when ploting test, you can view pred1 vs s(pred1, edf[1] ) & pred2 vs
s(pred2, edf[2] )
I would like to know if there is a way to access to those terms
(s(pred1) & s(pred2)). Does someone know how?
the purpose is to access to equation of smooths terms
2005 Feb 27
1
prediction, gam, mgcv
I fitted a GAM model with Poisson distribution
using the function gam() in the mgcv package.
My model is of the form:
mod<-gam(y~s(x0)+s(x1)+s(x2),family=poisson).
To extract estimates at a specified set of covariate
values I used the gam `predict' method.
But I want to get
estimate and standard error of the difference of two fitted values.
Can someone explain what should I do?
Thank
2005 Jan 13
2
GAM: Remedial measures
I fitted a GAM model with Poisson distribution to a data with about 200
observations. I noticed that the plot of the residuals versus fitted values
show a trend. Residuals tend to be lower for higher fitted values. Because,
I'm dealing with count data, I'm thinking that this might be due to
overdispersion. Is there a way to account for overdispersion in any of the
packages MGCV or GAM?
2004 Mar 09
4
help
Hello,
I am a new member, and I need your help.
For my work (thesis), I use the package rpart to construct trees.
But, to continu my studies, I need to calcule the 'variable importance'. But, I
don't find a program to do this in the implementation of R.
Is there someone who know if there exist a program which calculate the 'variable
importance', notion defined by Breiman and
2003 May 16
2
glm and gam confidence intervals
How can I obtain the values of confidence intervals from gam anf glm
objects?
Thanks in advance
--
David Nogu?s Bravo
Functional Ecology and Biodiversity Department
Pyrenean Institute of Ecology
Spanish Research Council
Av. Monta?ana 1005
Zaragoza - CP 50059
976716030 - 976716019 (fax)
2004 Dec 01
2
step.gam
Dear R-users:
Im trying (using gam package) to develop a stepwise analysis. My gam
object contains five pedictor variables (a,b,c,d,e,f). I define the
step.gam:
step.gam(gamobject, scope=list("a"= ~s(a,4), "b"= ~s(b,4), "c"= ~s(c,4),
"d"= ~s(d,4), "e"= ~s(e,4), "f"= ~s(f,4)))
However, the result shows a formula containing the whole
2005 Feb 14
1
gam(mgcv) starting values
Hi all!
I?ve got some problems with the function gam (library mgcv). For some
models I get the error message :
Error: no valid set of coefficients has been found:please supply
starting values
In addition: Warning message:
NaNs produced in: log(x)
This is a shortened code I used:
gam(y ~ M1 + M3 + M4 + M5 + M6 + sex + M1*M3 + s(age),
family=Gamma(link ="identity"),
weights=days)
If
2004 Sep 24
3
geographically weighted glm
Hi all,
I am interested in obtaining R code related to geographically weighted
regression.
In particular, I am interested in building geographically weighted
Poisson GLMs. The model will contain categorical and continuous x
independent variables, with interaction effects between categorical and
continuous variables.
Anybody have anything I can look at?
thanks,
Mark.
--
2004 Oct 12
3
need help on GAM
Get some question about the function "gam".
Suppose I have a semiparametric model,
Y~x1+x2+s(z1).
Using "gam", how could I get the estimates for the parametric part and
nonparametric part respectively?
And another question: we could find the coefficients for both
parametric term and nonparametric term, what do these coefficients
for the nonparametric term stand for, the
2003 Jun 03
3
gam questions
Dear all,
I'm a fairly new R user having two questions regarding gam:
1. The prediction example on p. 38 in the mgcv manual. In order to get
predictions based on the original data set, by leaving out the 'newdata'
argument ("newd" in the example), I get an error message
"Warning message: the condition has length > 1 and only the first element
will be used in: if