Displaying 20 results from an estimated 900 matches similar to: "integration problem"
2002 Apr 20
2
integration of a discrete function
Dear R list
I am looking for a function in R that computes the integration of a
discrete curve, such as a power spectrum, in a specified interval (in my
case, that would be 'power in a certain frequency band'). I found only
functions, such as 'integrate', that perform adaptive quadrature on
analytic functions, and not on a curve specified as a set of (x,y) pairs.
I have the
2006 Jul 19
3
Fitting a distribution to peaks in histogram
Hello list!
I would like to fit a distribution to each of the peaks in a histogram, such
as this: http://photos1.blogger.com/blogger/7029/2724/1600/DU145-Bax3-Bcl-xL.png
.
The peaks are identified using Petr Pikal peaks function (
http://finzi.psych.upenn.edu/R/Rhelp02a/archive/33097.html), but after that
I am quite stuck.
Any idea as to how I can:
Fit a distribution to each peak
Integrate the
2010 Nov 09
2
Help with Iterator
Dear Experts,
The following is my "Iterator". When I try to write a new function with
itel, I got error.
This is what I have:
> supDist<-function(x,y) return(max(abs(x-y)))
>
> myIterator <- function(xinit,f,data=NULL,eps=1e-6,itmax=5,verbose=FALSE) {
+ xold<-xinit
+ itel<-0
+ repeat {
+ xnew<-f(xold,data)
+ if (verbose) {
+ cat(
+
2007 Jan 26
2
Using functions within functions (environment problems)
Hi everyone,
I've been having difficulty writing wrapper functions for some
functions where those same functions include other functions with
eval()
calls where the environment is specified. A very simple example using
function lmer from lme4:
lmerWrapper <- function(formula, data, family = gaussian, method =
c("REML",
"ML", "PQL", "Laplace",
2009 May 15
2
Using column length in plot gives error
Hi
I'm trying to write a generic script for processing some data which finishes
off with some plots. Given Im never sure how many columns will be in my
dataframe I wanted to using the following
plot(spectra.wavelength, cormat, type = "l", ylim=c(-1,1), xlab="Wavelength
(nm)", ylab="Correlation")
however even if I specify as type="l" it appears plot
2009 Oct 27
4
automatically adjusting axis limits
Dear R users,
I am a newbie. Just switched from MATLAB. So thanks a lot for your
patience.
I have 50000 spectra collected in field. Each spectra has two columns :
Wavelength (56) and the actual measurement.
Each measurement came in a different .txt file on disk (50000 files in
total). I wrote a script that reads every spectra in a for loop and
constructs two variables :
Wavelength (56) and
2013 Oct 31
1
Extracting values from a ecdf (empirical cumulative distribution function) curve
Hi R users,
I am a new user, still learning basics of R. Is there anyway to extract y
(or x) value for a known x (or y) value from ecdf (empirical cumulative
distribution function) curve?
Thanks in advance.
Mano.
[[alternative HTML version deleted]]
2006 Jan 26
2
Prediction when using orthogonal polynomials in regression
Folks,
I'm doing fine with using orthogonal polynomials in a regression context:
# We will deal with noisy data from the d.g.p. y = sin(x) + e
x <- seq(0, 3.141592654, length.out=20)
y <- sin(x) + 0.1*rnorm(10)
d <- lm(y ~ poly(x, 4))
plot(x, y, type="l"); lines(x, d$fitted.values, col="blue") # Fits great!
all.equal(as.numeric(d$coefficients[1] + m
2007 Nov 08
6
Extract correlations from a matrix
Dear R users,
suppose I have a matrix of observations for which I calculate all
pair-wise correlations:
m=matrix(sample(1:100,replace=T),10,10)
w=cor(m,use="pairwise.complete.obs")
How do I extract only those correlations that are >0.6?
w[w>0.6] #obviously doesn?t work,
and I can?t find a way around it.
I would very much appreciate any help!
Best wishes
Christoph
(using R
2005 Oct 04
3
Problem reading in external data and assigning data.frames within R
Hey there,
I apologize if this is an irritatingly simple question ... I'm a
new user. I can't understand why R flips the sign of all data values
when reading in external text files (tab delimited or csv) with the
read.delim or read.csv functions. The signs of data values also seem
to be flipped after assigning a new data.frame from within R (xnew <--
edit(data.frame()). What am
2011 Jun 10
2
How do I make proper use of the by() function?
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2010 Apr 22
1
Convert character string to top levels + NAN
Dear all,
I have several character strings with a high number of different levels.
unique(x) gives me values in the range of 100-200.
This creates problems as I would like to use them as predictors in a coxph
model.
I therefore would like to convert each of these strings to a new string
(x_new).
x_new should be equal to x for the top n categories (i.e. the top n levels
with the highest
2004 Oct 22
3
pgamma discontinuity (PR#7307)
Full_Name: Morten Welinder
Version: 2
OS: Solaris/space/gcc2.95.2
Submission from: (NULL) (65.213.85.217)
I changed src/nmath/standalone/test.c to read:
---------------------------------------------------------------------------------
#define MATHLIB_STANDALONE 1
#include <Rmath.h>
#include <stdio.h>
int
main()
{
double x;
for (x = 99990; x <= 100009; x++)
printf
2001 May 23
1
Passing a string variable to Surv
Hi,
I am trying to write a function to automate multiple graph
generation. My data looks like:
Table of numeric values with the following headers:
timeM1 statusM1 xM1 timeM2 statusM2 xM2 timeM3 statusM3 xM3
1
2
3
4
5
6
Where M1,M2, M3 hve no similarity except they have a max string length
of 7. Examples are mcw0045, adl0003, lei0101.
Now, what I want to do is
Function(M1, M2,
2005 Jan 07
6
coercing columns
Dear all,
I have a data frame that looks like this:
c1 c2 c3
A B C
B C A
A A B
and so on;
I?d like to produce one single vector consisting of the columns c1,c2,
c3, such that
vector=("A","B","A","B","C","A","C","A","B")
I guess it?s easy to do but I don?t know how...Can anyone
2002 Nov 22
4
Use of variables to reference to objects
Hi,
I'm new to R and looking for a way to use a variable to reference to an
object.
I'm plotting several graphs on top of each other and want to do this by
a for loop. The field I want to graph have names like a1,a2,a3, ...
I can't figure out how to get this working:
It should look like this:
lines(spectral$Wavelength,paste("spectral$a",j,sep=""),col=j)
but
2012 Apr 24
1
Nested longitudinal data
Hi,
I have some difficulty in figuring out whether I am doing correct or not.
A brief introduction about the work: It is a light/dark choice test
conducted in insect larvae. The response is binary (0- present in dark
area, 1-present in light area) and the experiment is run for 15 min, so
there are 15 repeated measurements per individual larva at 1 min
intervals. The factors which affect
2012 Jan 20
1
Calling Windows DLL using .C; function name not known but in exports.
First time ever that I try to call subroutines in a Win DLL using R.
Have done this before using VBA and Python.
The C code's function argument list contains only double pointers
(double *x). The function is declared void, the output value is one of
the arguments.
C calling sequence is used.
When inspecting the exports of the DLL with dumpbin I can see that the
function I need is
2008 Nov 06
2
replacing characters in formulae / models
Dear all,
How can I replace text in objects that are of class "formula"?
y="a * x + b"
class(y)="formula"
grep("x",y)
y[1]
Suppose I would like to replace the "x" by "w" in the formula object "y".
How can this be done? Somehow, the methods that can be used in character objects do not work 1:1 in
formula objects...
Many
2011 May 09
6
Posfix and Dovecot (dovecot like LDA) and no space left on the disk
Hi,
Please I have a question:
If my server is out of space (disk full) and the postfix is LDA, the new messages a deffered or refused,so postfix send 450 to sender ...
But When I use dovecot (1.2.16) like LDA, postfix accept message (even there is no space), forward to dovecot, dovecot REFUSE the message and message is lost !
How can I solve this ? I don't want tu use quota and the disk