Displaying 20 results from an estimated 10000 matches similar to: "Spline"
2009 Oct 12
3
help with the use of mtext to create main title over multiple plots
I'm trying to use mtext to create a main title over multiple plots. Below is
a simple self-contained example and my sessionInfo (I should note I've also
tried this with R-2.8.1 with the same results). When I execute the code
chunk below, I get the plots, but no title. I've tried this using the screen
driver, pdf, and postscript. I've used different sizes of paper. I suspect I
am
2009 Dec 19
1
model matrix with a spline
Hi all
I want to get the design matrix for a model, evaluated at a single value.
For example, if I pass in a data frame with a=2, b=2, y=3, and my
model is y ~ a+b+a:b, then I would like to get
the values 3, 2, 2, 4 out. I can do this with:
tmp <- model.matrix(fit, data=mydata)
or
tmp <- predict(fit, newdata=mydata, type="terms")
However, if the fit had a smoothing spline
2003 Aug 14
2
Using spline parameters to generate data
# I need to generate some data. I'm modeling some time series that follow
a
# negative exponential decay (mostly). I have 20 samples that can easily
be fit with cubic splines.
# What I want to do is generate many thousands of similar samples using
the parameters from the splines
# For instance one data sample looks not unlike this:
foo.curve <- 1 * exp(-0.01 * 1:500) + 0.5
2011 Sep 20
2
Multivariate spline regression and predicted values
Hello,
I am trying to estimate a multivariate regression of Y on X with
regression splines. Y is (nx1), and X is (nxd), with d>1. I assume the
data is generated by some unknown regression function f(X), as in Y =
f(X) + u, where u is some well-behaved regression error. I want to
estimate f(X) via regression splines (tensor product splines). Then, I
want to get the predicted values for some new
2013 Mar 06
1
Constrained cubic smoothing spline
Hello everone,
Anyone who knows how to force a cubic smoothing spline to pass through a particular point?
I found on website someone said that we can use "cobs package" to force the spline pass through certain points or impose shape constraints (increasing, decreasing). However, this package is using B-spline and can only do linear and quadratic
2000 Sep 04
2
bug in spline()? (PR#653)
BUG IN SPLINE()?
Version R-1.0.1, system i486,linux
If the spline(x,y,method="natural") function is given values outside the
range of the data, it does not give a warning. Moreover, the extrapolated
value reported is not the ordinate of the natural spline defined by (x,y).
Example. Let x <- c(2,5,8,10) and y <- c(1.2266,-1.7606,-0.5051,1.0390).
Then interpolate/extrapolate with
2012 Mar 12
1
Fwd: Re[2]: B-spline/smooth.basis derivative matrices
--- On Mon, 3/12/12, aleksandr shfets <a_shfets at mail.ru> wrote:
> From: aleksandr shfets <a_shfets at mail.ru>
> Subject: Fwd: Re[2]: [R] B-spline/smooth.basis derivative matrices
> To: "Vassily Shvets" <shv736 at yahoo.com>
> Received: Monday, March 12, 2012, 5:15 PM
>
>
>
> -------- ???????????? ?????????
> --------
> ?? ????:
2006 Jul 31
1
questions regarding spline functions
Greetings,
A couple general questions regarding the use of splines to interpolate depth
profile data.
Here is an example of a set of depths, with associated attributes for a given
soil profile, along with a function for calculating midpoints from a set of
soil horizon boundaries:
#calculate midpoints:
mid <- function(x) {
for( i in 1:length(x)) {
if( i > 1) {
a[i] = (x[i] -
2001 Dec 05
4
Questions about piecewise spline fitting
Hi All,
I want to fit a piecewise spline of degree 1, i.e. a spline consisting of a
straight line over each piece. I downloaded the R package pspline, then I
have following questions:
1. in the program, the degree of the spline is specified by 2*norder-1. Why
do they adopt such scheme that we can only fit a spline with odd degree?
2. norder cannot be set to 1. Is there any specific reason
2008 Jul 17
1
smooth.spline
I like what smooth.spline does but I am unclear on the output. I can see from the documentation that there are fit.coef but I am unclear what those coeficients are applied to.With spline I understand the "noraml" coefficients applied to a cubic polynomial. But these coefficients I am not sure how to interpret. If I had a description of the algorithm maybe I could figure it out but as it
2008 Dec 16
1
Application b-spline basis for polynomial splines
Hai everbody, Is there anyone have simple application b-spline in r language? I need it for make me understanding about b-spline for polynomial spline.
thank u
Arif
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2010 Apr 09
1
How to get the penalty matrix for natural cubic spline?
Hi, all
I am trying to get the basis matrix and penalty matrix for natural
cubic splines. In the "splines" package of R,"ns" can
generate the B-spline basis matrix for a natural cubic spline. How can
I get the basis matrix and penalty matrix for natural cubic
spline.
Thanks a lot!
Lee
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2001 Apr 26
3
Installing smooth.spline command
Hello
I have installed R-0.90.1 on my Linux (Redhat 6.2) machine,
unfortunately I am not able to use a number of commands like e.g.
smooth.spline and predict.smooth.spline.
The error messages being given by is:
Error: Object "smooth.spline" not found
With the command library() I have checked or the libraries for the
smoothing functions are there, as shown below.
--------
>
2012 Feb 24
1
B-spline/smooth.basis derivative matrices
Hello,
I've noticed that SPLUS seems to have a function for evaluating derivative matrices of splines. I've found the R function that evaluates matrices from 'smooth.spline'; maybe someone has written something to do the same with smooth.basis?
regards,
s
2003 Apr 07
3
spline with multiple predictor vars?
Hi, is there a way in R to generate a polynomial spline with multiple predictor
variables? I have one response and two predictors and I'm trying to fit a
spline model for this...
Please cc me on the reply..
Thanks,
nirmal
1998 Apr 07
3
R-beta: spline problems(?)
Hi,
I am a total beginner with this whole thing so please have patience!
I am trying to run an S-plus program with a certain line:
spline(1:nrow(y), y[,1],n=100);
This crashes with:
Error: NAs in foreign function call (arg 8)
Apparently, this is caused by the last command of spline:
u <- seq(xmin, xmax, length.out = n)
.C("spline_eval", z$method, length(u), x = u, y =
2011 Aug 06
1
How to estimate confidential intervals for the derivatives of cubic smoothing spline
Dear all,
I want to use smooth.spline to construct a cubic smoothing spline and its first
derivative to my data. However, the predict.smooth.spline does not seem to
provide a SE for both the fitted values and their derivatives. How should I
calculate it?
Thank you very much,
Bingzhang
2012 Feb 24
1
evaluating derivative matrices of spline functions
Hello,
I've noticed that SPLUS has a function for evaluating the derivative matrices of splines.
I've also noticed that there's a function in R for evaluating matrices from smooth.spline;
maybe someone knows if something has been written to evaluate matrices from 'smooth.basis'?
regards,
s
2009 Mar 31
2
How to generate natural cubic spline in R?
Suppose I have two var x and y,now I want to fits a natural cubic
spline in x to y,at the same time create new var containing the
smoothed values of y. How can I get it?
2002 Feb 20
2
How to get the penalized log likelihood from smooth.spline()?
I use smooth.spline(x, y) in package modreg and I would like to get
value of penalized log likelihood and preferable also its two parts. To
make clear what I am asking for (and make sure that I am asking for the
right thing) I clarify my problem trying to use the same notation as in
help(smooth.spline):
I want to find the natural cubic spline f(x) such that
L(f) = \sum_{k=1}{n} w[k](y[k] -