Displaying 20 results from an estimated 400 matches similar to: "basic cubic spline smoothing (resending because not sure about pending)"
2009 Sep 24
1
basic cubic spline smoothing
Hello,
I come from a non statistics background, but R is available to me,
and I needed to test an implementation of smoothing spline that I have
written in c++, so I would like to match the results with R (for my unit
tests)
I am following
http://www.nabble.com/file/p25569553/SPLINES.PDF SPLINES.PDF
where we have a list of points (xi, yi), the yi points are random such that:
y_i = f(x_i) +
2010 Apr 19
0
Natural cubic splines produced by smooth.Pspline and predict function in the package "pspline"
Hello,
I am using R and the smooth.Pspline function in the pspline package to
smooth some data by using natural cubic splines. After fitting a
sufficiently smooth spline using the following call:
(ps=smooth.Pspline(x,y,norder=2,spar=0.8,method=1)
[the values of x are age in years from 1 to 100]
I tried to check that R in fact had fitted a natural cubic spline by
checking that the resulting
2003 Oct 23
1
Variance-covariance matrix for beta hat and b hat from lme
Dear all,
Given a LME model (following the notation of Pinheiro and Bates 2000) y_i
= X_i*beta + Z_i*b_i + e_i, is it possible to extract the
variance-covariance matrix for the estimated beta_i hat and b_i hat from the
lme fitted object?
The reason for needing this is because I want to have interval prediction on
the predicted values (at level = 0:1). The "predict.lme" seems to
2002 Mar 29
1
help with lme function
Hi all,
I have some difficulties with the lme function and so this is my problem.
Supoose i have the following model
y_(ijk)=beta_j + e_i + epsilon_(ijk)
where beta_j are fixed effects, e_i is a random effect and
epsilon_(ijk) is the error.
If i want to estimate a such model, i execute
>lme(y~vec.J , random~1 |vec .I )
where y is the vector of my data, vec.J is a factor object
2008 Feb 14
1
Winbind problem with more details.
Everyone,
One of our developers was kind enough to insert some bug checking into the mod_auth_pam and mod_auth_sys_group so that we could see a little more of what was going on with our authentication failures. Here is what we just saw. Two of our users NA\connelmp and NA\guminssa both started getting messages that they were not part of the required group. Here is the log for
2003 Mar 29
1
Goodness of fit tests
I have a dataset which I want to model using a Poisson distribution, with a given parameter. I would like to know what is the proper way to do a ''goodness of fit'' test using R.
I know the steps I''d take if I were to do it ''manually'': grouping the numbers into classes, calculating the expected frequencies using ''ppois'', then
2006 Nov 21
3
Fitting mixed-effects models with lme with fixed error term variances
Dear R users,
I am writing to you because I have a few question on how to fix
the error term variances in lme in the hope that you could help me. To
my knowledge, the closest possibility is to fix the var-cov structure,
but not the whole var-cov matrix. I found an old thread (a few years
ago) about this, and it seems that the only alternative is to write the
likelihood down and use optim or a
2001 Dec 13
1
Code for Hodrick-Prescott Filter: Special Case of smooth. spline?
I've had a play with this and, due to my own short-comings, remain none the
wiser.
In particular, I'm not sure what value of 'spar' is consistent with the
magic lambda=1/1600 for quarterly data.
I initially interpreted spar as lambda and tried setting spar=1/1600. This
results in almost no smoothing while spar=1600 causes an error. The
smooth.spline function seems to want
2007 Jun 14
0
random effects in logistic regression (lmer)-- identification question
Hello R users!
I've been experimenting with lmer to estimate a mixed model with a
dichotomous dependent variable. The goal is to fit a hierarchical
model in which we compare the effect of individual and city-level
variables. I've run up against a conceptual problem that I expect one
of you can clear up for me.
The question is about random effects in the context of a model fit
with a
2006 Feb 10
1
Lmer with weights
Hello!
I would like to use lmer() to fit data, which are some estimates and
their standard errors i.e kind of a "meta" analysis. I wonder if weights
argument is the right one to use to include uncertainty (standard
errors) of "data" into the model. I would like to use lmer(), since I
would like to have a "freedom" in modeling, if this is at all possible.
For
2008 Feb 13
1
Problem with winbind not seeing a user as part of a group
Everyone,
Here is a challenge for all of you samba experts! Lately I have been seeing a problem where winbind is not correctly identifying a user as a member of a group he most certainly belong to. This is with a Domain Local group so I know samba should support it.
Users access a HTTPS (SSL) webpage that is secured by a Domain Local group. Sometimes they get in,
2010 Jun 18
1
ow to apply a panel function to each of several data series plotted on the same graph in lattice
Hi
is it possible to fit a trend line (or some other panel function) through each of multiple data series plotted on the same graph? Specifically, while one can do something like
xyplot(a+b+c~x)
which plots three series, a,b & c, but can one automatically fit lines through each of them?
I suppose one could generate three more variables afit, bfit, and cfit with a model & predict and
2004 Apr 09
1
loess' robustness weights in loess
hi!
i want to change the "robustness weights" used by loess. these
are described on page 316 of chambers and hastie's "statistical models in S"
book as
r_i = B(e_i,6m)
where B is tukey's biweight function, e_i are the residulas, and m is the
median average distance from 0 of the residuals. i want to
change 6m to, say, 3m.
is there a way to do this? i cant
2008 Oct 10
0
Problems and bugs in vgam()
Hello R-Users,
I have recently run into several problems using vgam() in the VGAM
package. I am hoping someone might have some solutions...
Briefly, I have been trying to fit GAM models for zero-altered negative
binomial models.
1. When fitting smoothed parameters (e.g. s(X, df=2)) changing the
degrees-of-freedom has no effect on the level of smoothing (e.g. number
of knots for the
2006 Apr 21
1
Linker problem in installing 64-bit R
Hi,
I am trying to compile R-2.2.1 on Solaris 2.9 with a 64-bit build. Following
the instructions in "R Installation and Adminstration", I changed the
following settings in "config.site":
CC="gcc -m64"
F77="g77 -64"
CXX="g++ -m64"
LDFLAGS="-L/usr/local/lib/sparcv9 -L/usr/local/lib"
But I got the following error messages:
1999 Jan 21
2
scoping problem?
Dear R-helpers: (this is part of a bigger program)
the following fails as a function, but runs OK
if we comment out the fnfn_ function() line.
Any hint would be appreciated. -Yudi-
R : Copyright 1998, The R Development Core Team
Version 0.63.0 Beta (Nov 13, 1998) -- on WIndows3.11
fnfn _ function (m=10,n=10,spar=2)
{
fn _ function(u,v){
uc_ u-floor(m/2)-1
vc_ v-floor(n/2)-1
2003 Apr 01
2
predict in Pspline package (PR#2714)
To whom it may concern,
I don't know whether this is really a bug with the Pspline package or
only a problem with my installation. Things work fine in Linux but
not in Mac OS X (Darwin). Both system run the latest public versions
of R and Pspline.
predict.smooth.Pspline produces only NaN instead of predicted values
when norder>2:
> library (Pspline)
> tt <- seq
2009 Apr 04
2
Help using smooth.spline with zoo object
Can someone please show me how to smooth time series data that I have in the form of a zoo object?
I have a monthly economies series and all I really need is to see a less jagged line when I plot it.
If I do something like
s <- smooth.spline(d.zoo$Y, spar = 0.2)
plot(predict(s,index(d.zoo)), xlab = "Year")
# not defined for Date objects
and if I do something like
2004 Nov 08
1
how lambda is computed in smoot.spline given _df_
Hi,
I posted some days ago a question concerning the computation of lambda in the smooth.spline function (which I repreat at the bottom of the mail) given _df_ .
Unfortunately the documentation is not clear to me. Maybee someone can help to answer in my view the basic question:
If the penalized log likelihood is L = (y - f)' W (y - f) + lambda c' Sigma c
how the _lambda_ in the above
2007 Jul 16
0
Spline - frequency response
Please preemptively excuse my ignorance.
I'm trying to fit a cubic smoothing spline to a time series according to a
method encountered in a paper. The authors state that they fit a spline
whose frequency response is 50% at a wavelength of n years where n is 67% of
the length of the time series. Is it possible to fit a spline like this in R
using the spar parameter in smooth.spline? Or is