Displaying 20 results from an estimated 9000 matches similar to: "Predicted points in splines"
2012 Jun 05
1
Do YOU know an equation for splines (ns)?
Hi,
I am looking at the change in N concentration in plant roots over 4 time
points and I have fit a spline to the data using ns and lme:
fit10 <- lme( N~ns(day, 3), data = rcn10G)
I may want to adjust the model a little bit, but for now, let's assume it's
good. I get output for the fixed effects:
Fixed: N ~ ns(day, 3)
(Intercept) ns(day, 3)1 ns(day, 3)2 ns(day, 3)3
2011 Feb 05
3
spline interpolation
Hello R-help
I have the following data for a standard curve
concentration(nM),fluorescence
0,48.34
2,58.69
5,70.83
10,94.73
20,190.8
50,436.0
100, 957.9
(1)Is there function in R to plot a spline.
(2)How can I interpolation,say 1000 point from 0nM-100nM and store this as a
data frame of concentration,fluorescence
(3)How can I modify the code below so that instead of retrieving a concentration
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
2012 May 31
0
splines and ns equation
Hi,
I am looking at the change in N concentration in plant roots over 4 time
points and I have fit a spline to the data using ns and lme:
fit10 <- lme( N~ns(day, 3), data = rcn10G)
I may want to adjust the model a little bit, but for now, let's assume it's
good. I get output for the fixed effects:
Fixed: N ~ ns(day, 3)
(Intercept) ns(day, 3)1 ns(day, 3)2 ns(day, 3)3
1.15676524
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
2011 Jan 20
1
Inverse Prediction with splines
Hello, I have fit a simple spline model to the following data.
Data
x y
0 1.298
2 0.605
3 0.507
4 0.399
5 0.281
6 0.203
7 0.150
8 0.101
Model
Sp.1=lm(y~bs(x,df=4))
Now I wish to inverse predict the x for y=.75, say. Optimize works fine
for a polynomial but I can figure out how to get the spline model into
the function argument.
Can anyone help me out.
Thanks!!
Jeff
Jeff Morris
Sanofi
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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2006 Nov 07
1
multivariate splines
Hi,
I am looking for an R package that would calculate multivarite (mostly
2d and 3d, tensor) cubic interpolating splines, so that I could
evaluate these splines (and their derivatives) at many points (unkown
at the time of calculating the spline polynomials) repeatedly.
To make things concrete, I have an array V with
dim(V) = k
and gridpoint vectors grid=list(...), length(grid[[i]])==k[i],
2010 May 11
1
Splines under tension
Does anyone know if R has a function for splines under tension. I know there
are numerous packages for spline interpolation within R i just can't find
one that lets you determine the tension factor.
Any help would be much appreciated!
Sam
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2004 Apr 09
2
Regression models w/ splines
Hi - I am fitting various Cox PH models with spline predictors. After
fitting the model, I would like to use termplot() to examine the
functional form of the fitted model (e.g., to obtain a plot of the
relative risk (or log r.r.) versus the predictors).
When there is only 1 predictor in the model, termplot returns a "?".
In this case, I have not been able to figure out how to create
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
2006 Jun 24
2
smoothing splines and degrees of freedom
Hi,
If I set df=2 in my smooth.spline function, is that equivalent to running
a linear regression through my data? It appears that df=# of data points
gives the interpolating spline and that df = 2 gives the linear
regression, but I just want to confirm this.
Thank you,
Steven
2007 Oct 05
2
Splines
I want to fit a cubic spline of x on y. where :
x
[1] 467 468 460 460 450 432 419 420 423 423
y
[1] 1 2 3 4 5 6 7 8 9 10
using the syntax
spline(y, x)
I got following output :
$x
[1] 1.000000 1.310345 1.620690 1.931034 2.241379 2.551724 2.862069
[8] 3.172414 3.482759 3.793103 4.103448 4.413793 4.724138 5.034483
[15] 5.344828 5.655172
2002 May 02
1
splines
I've got a problem with the R function spline.des.
I use the following arguments:
x_seq(0,1,length=200)
knot_quantile(x,(1:8)/9)
ord_3
k_sort(c(rep(range(x),ord,knot)))
derivs_rep(2,200)
When I do spline.des(k,x,ord,derivs)$design on Splus and on R, I don't
have the same results.
However, if I take an order ord=4 (ie a spline of degree 3), then, I
have the same
2011 Jul 19
2
Incorrect degrees of freedom for splines using GAMM4?
Hello,
I'm running mixed models in GAMM4 with 2 (non-nested) random intercepts and
I want to include a spline term for one of my exposure variables. However,
when I include a spline term, I always get reported degrees of freedom of
less than 1, even when I know that my spline is using more than 1 degree of
freedom. For example, here is the code for my model:
>
2009 Jul 05
2
integrar resultado de splines cubicos
hola soy nuevo usuario de R y necesito crear un objeto p tal que,
p=lambda*integral[f´´(x)^2 dx ]
donde "lambda" es uno de los parametros que resultan de la funcion
"smooth.spline()" y la integral es sobre la derivada 2 de esa misma
funcion...
dos cuestiones:
1) como extraigo lambda de los resultados de smooth.spline() para usarlo
como objeto cuando lo requiera y
2) como
2013 Apr 23
1
GAM Penalised Splines - Intercept
Hey all,
I'm using the gam() function inside the mgcv package to fit a penalised spline to some data. However, I don't quite understand what exactly the intercept it includes by default is / how to interpret it.
Ideally I'd like to understand what the intercept is in terms of the B-Spline and/or truncated power series basis representation.
Thanks!
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 Jan 09
1
What is the function for "smoothing splines with the smoothing parameter selected by generalized maximum likelihood?
Dear all,
I am new to R, and I am a biotechnologist, I want to fit a smoothing spline
with smoothing parameter selected by generalized maximum likelihood. I was
wondering what function implement this, and, if possible how I can find the
fitted results for a certain point (or predict from the fitted spline if
this is the correct language)
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2008 May 01
1
Optimal knot locations for splines
Suppose I have two variables, x and y. For a fixed number of knots, I want
to create a spline transformation of x such that a loss function is
minimized. Presumably, this loss function would be least squares, i.e. sum
(f(x)-y)^2. The spline transformations would be linear, quadratic or
cubic. I know I can solve this problem using some optimization function in
R, but I was wondering if anyone