Displaying 20 results from an estimated 10000 matches similar to: "the c implementation of loess"
2011 Oct 07
1
loess question
Hi All,
I am trying to use loess to smooth a 2D image, and also obtain the
standard error for every pixel. I see that the standard error does not
make sense. For example, running the following:
library(stats)
x <- array(c(1:100), dim=c(100,100))
y <- t(x)
v <- exp(-((x-50)^2+(y-50)^2)/30^2)
s <- v*0.02
g_noise <- rnorm(10000, mean = 0, sd = s)
f <- v + g_noise
f.loess <-
2012 May 03
1
cannot calculate standard estimate with predict on loess
Hi,
For some reason I have been unable to use the predict function when I
desire the standard error to be calculated too. For example, when I try
the following:
l<- loess(d~x+y, span=span, se=TRUE)
p<- predict(l, se=TRUE)
I get the following error message:
Error in vector("double", length) : vector size cannot be NA
In addition: Warning message:
In N * M1 : NAs produced by
1998 Nov 24
1
Loess & Tar file
Hi,
First time on this list. Here it goes
I am trying to find Loess. I could not find it on the windows version. Is
there one in either Unix version of R or some C program somewhere?
I tried one from http://netlib.bell-labs.com/netlib/a/, but I cannot get
it to compile due to problem with missing lib (I think):
cc -o gas.x gas.o loessc.o loess.o predict.o misc.o loessf.o -llinpack -lcor
-lm
2011 Jun 14
0
2d loess question
Hi,
We have been trying to use loess on 2D data (basically a matrix) in the
following way:
x <- 1:256
y <- 1:256
z <- data # input from data
z.loess = loess(z ~ x + y)
We get a 256 x 1 vector of fitted values with a 256 x 256 array of
residuals,
but not a 256 x 256 array of fitted values.
Why would this be? I think we are using loess incorrectly but can't
figure out what is
1999 Jul 16
0
Contractor needed for MSVC wrapper to Loess
Hi,
Our firm is looking to see if it is possible to wrap some of more advanced lib
in R like modreg.dll and specifically Loess function in there for both
regression and prediction into MSVC++. We will probably take it to either VB or
Python for implementation issues. Given that locfit has many utitlities built in
for data transformation, this would be a good thing.
If that's not
2010 May 05
0
A question regarding the loess function
Hello,
I was hoping that someone familiar with the implementation details of the
loess algorithm might be able to help me resolve some difficulties I am
having. I am attempting to reproduce some of the functionality of the
loess() function in C++. My primary motivation is that I would like to
understand the algorithm in detail.
So far I have managed to create a working port in C++ for the
2013 Mar 01
1
predict.loess() segfaults for large n?
Hi,
I am segfaulting when using predict.loess() (checked with r62092).
I've traced the source with the help of valgrind (output pasted
below) and it appears that this is due to int overflow when
allocating an int work array in loess_workspace():
liv = 50 + ((int)pow((double)2, (double)D) + 4) * nvmax + 2 * N;
where liv is an (global) int. For D=1 (one x variable), this
overflows at
2009 Jul 01
2
getOptions("max.print") in R
I am typing the following on the command prompt:
>variab = read.csv(file.choose(), header=T)
>variab
It lists 900,000 ( this is the total number of observations in "variab" )
minus 797124 observations and prompts the following message
[ reached getOption("max.print") -- omitted 797124 entries ]]
Is there a way to see the entire set of data, ie all of 900,000 obs, and
2006 Nov 23
1
loess lines in xyplot with two or more variables on the left side of a formula
Hello:
I recall something like this being discuss recently, but I can't seem
to locate an example in the archives. I have data like the following:
df <- expand.grid(1:4, 1992:2002)
names(df) <- c("MSA", "YEAR")
df$IDUPREV <- runif(44)
df$VALIDAT <- rnorm(44)
I want to create an xyplot() with separate loess lines for each series
(IDUPREV and VALIDAT) in
2009 Jul 11
2
Heckman Selection Model/Inverse Mills Ratio
I have so far used the following command
glm(formula = s ~ age + gender + gemedu + gemhinc + es_gdppc +
imf_pop + estbbo_m, family = binomial(link = "probit"))
My question is
1. How do i discard the non significant selection variables (one out of the
seven variables above is non-significant) and calculate the Inverse Mills
Ratio of the significant variables
2. I need the inverse
2006 Jul 07
0
User Error (was LOESS (PR#9064))
Please do as we ask (repeatedly) and study the help page before posting.
'family' is a separate argument, not part of loess.control, as the help
page correctly documents. If you use
cars.lo2 <- loess(dist ~ speed, cars, family = "symmetric",
control = loess.control(surface = "direct", iterations = 20))
cars.lo2$pars$iterations
it prints *20*, as it is
2009 Oct 18
2
How to create MULTILEVELS in a dataset??
Dear R users
I have a data set which has five variables. One depenedent variable y, and 4
Independent variables (education-level, householdincome, countrygdp and
countrygdpsquare). The first two are data corresponding to the individual
and the next two coorespond to the country to which the individual belongs
to. My data set does not make this distinction between individual level and
country
2007 Jul 25
3
loess prediction algorithm
Hello,
I need help with the details of loess prediction algorithm. I would like
to get it implemented as a part of a measurement system programmed in
LabView. My job is provide a detailed description of the algorithm. This
is a simple one-dimensional problem - smoothing an (x, y) data set.
I found quite a detailed description of the fitting procedure in the "white
book". It is also
2008 Jun 03
1
'asymmetric span' for 2D loess?
Hello,
I am interested in performing a 2D loess smooth on microarray data, i.e.
log2 ratios on a 2D grid, using different spans in the horizontal and
vertical directions (the immediate reason being that replicate spots are
laid out in the horizontal direction). Is it possible to do this in R?
Functions like loess(stats) seem to apply the same span for all
predictors, which carries over to
2011 Jun 11
0
Is there an implementation of loess with more than 3 parametric predictors or a trick to a similar effect? [re-posting as plain text to pass char-set filter]
Dear R experts,
I have a problem that is a related to the question raised in this earlier post
??? https://stat.ethz.ch/pipermail/r-help/2007-January/124064.html
My situation is different in that I have only 2 predictors
(coordinates x,y) for local regression but a number of global
("parametric") offsets that I need to consider.
Essentially, I have a spatial distortion overlaid over a
2011 Jun 16
0
Update: Is there an implementation of loess with more than 3 parametric predictors or a trick to a similar effect?
Dear R developers!
Considering I got no response or comments in the general r-help forum
so far, perhaps my question is actually better suited for this list? I
have added some more hopefully relevant technical details to my
original post (edited below).
Any comments gratefully received!
Best regards,
David Kreil.
----------
Dear R experts,
I have a problem that is a related to the question
2009 Jun 29
2
Large Stata file Import in R
Hi
I am using Stata 10 and I need to import a data set in stata 10 to R, I have
saved the dataset in lower versions of Stata as well by using saveold
command in Stata.
My RAM is 4gb and the stata file is 600MB, I am getting an error message
which says :
"Error: cannot allocate vector of size 3.4 Mb
In addition: There were 50 or more warnings (use warnings() to see the first
50)"
Thus
2011 Jun 24
2
Is there an implementation of loess with more than 3 parametric ...
Dear John,
> I suggest that you look at the abilities of the mgcv package.
> There are notes of mine at
>
> http://www.maths.anu.edu.au/%7Ejohnm/r-book/xtras/autosmooth.pdf
>
> that may help you get started.
Thank?you very much for the suggestion and the link to your write-up,
it was indeed very helpful!
I have experimented with this library for a while now and am really
happy
2011 Jun 11
1
Is there an implementation loess with more than 4 parametric predictors or a trick to similar effect?
Dear R experts,
I have a problem that is a related to the question raised in this earlier
post
https://stat.ethz.ch/pipermail/r-help/2007-January/124064.html
My situation is different in that I have only 2 predictors (coordinates x,y)
for local regression but a number of global ("parametric") offsets that I
need to consider.
Essentially, I have a spatial distortion overlaid over a
2009 Jul 12
2
Heckman Selection MOdel Help in R
Hi Saurav!
On Sun, Jul 12, 2009 at 6:06 PM, Pathak,
Saurav<s.pathak08 at imperial.ac.uk> wrote:
> I am new to R, I have to do a 2 step Heckman model, my selection equation is
> below which I was successful in running but I am unable to proceed further,
>
>
>
> I have so far used the following command
>
> glm(formula = s ~ age + gender + gemedu + gemhinc + es_gdppc +