Displaying 20 results from an estimated 800 matches similar to: "Fitting a distribution to peaks in histogram"
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 15
1
Find peaks in histograms / Analysis of cumulative frequency
Hello all,
I have some histograms of amount of DNA in some cells (DU145 cells
overexpressing Bax and Bcl-xL for those who wish to know). The histograms
show not only two peaks as expected, but three, indicating that some cells
have more than normal amounts of DNA.
I am interested in knowing how much of the cell populations are in each peak
as well as between.
I am not really sure how to go
2004 Oct 26
2
integration problem
Dear R users,
I have spectral data (say, wavelength vs. extinction coefficient) for
which I??d like to calculate an integral (i.e. the area underneath the
curve).
Suppose the (artificial) dataset is
lambda E
1 2
2 4
3 5
4 8
5 1
6 5
7 4
8 9
9 8
10 2
How can I calculate an integral for these values using R?
Many thanks for any help!
Regards
Christoph
2011 Jun 10
2
How do I make proper use of the by() function?
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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
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
2011 Feb 18
1
Find peaks in dataset(x,y) and area for each peak
http://r.789695.n4.nabble.com/file/n3312061/x_and_y_values.txt
x_and_y_values.txt
I have the absorbance values form HPLC Chromatogram. I need to find the
peaks in datapoints and area under each peak.
I am not sure how how to find the peaks, I tried couple of libraries and
peak function but they return me a list of values which when computed from
area turns out to be huge nnumbers. In the
2009 Oct 07
1
inconsistency in return value of peaks() {splus2R} (PR#13988)
Full_Name: Benny van der Vijgh
Version: 2.7.2
OS: Windows Vista
Submission from: (NULL) (194.171.252.108)
The return value of peaks() in package splus2R is not consistent.
This is because of the call to max.col() without additional parameters which
peaks() makes.
max.col() has a parameter 'ties.method' which specifies how ties are handled,
with "random" by default.
This means
2010 Dec 23
1
Finding flat-topped "peaks" in simple data set
Hello,
Thank you to all those great folks that have helped me in the past
(especially Dennis Murphy).
I have a new challenge. I often generate time-series data sets that look
like the one below, with a variable ("Phase") which has a series of
flat-topped peaks (sample data below with 5 "peaks"). I would like to
calculate the phase value for each peak. It would be great to
2013 Aug 29
1
Problem with "Peaks" package - followup…
Hi,
I apologize for not following the posting rules?
Here is the text from my previous post:
"I started evaluating the 'Peaks' package a couple of months ago and found it to be quite
useful. Getting back to it last week I had to set up my R environment due to hardware
changes again. The Peaks package loads with no problem.
After successfully reinstalling all packages (RedHat
2002 May 28
2
peaks
I am looking for a function in R that is equivalent to the function
"peaks" in
Splus. This function gives the local maxima of a vector.
I do not find it using the help and I 'm not sure it exits in R.
Could someone help me ?
Thanks,
Herve Cardot
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2006 Jan 04
1
Selecting significant peaks in periodograms
Greetings all,
I am using Fourier analysis to search for periodicities in IP network traffic by generating periodograms and then visually examining them for large, distinct peaks.
However, in many cases it is not readily apparent where there are periodicities. I have no experience with discrete maths so I've come up against a block here: How do I define what the "noise floor"
2007 Feb 08
1
Suggestion about "R equivalent of Splus peaks() function"
In 2004 there was this R-Help posting from Jan 2004:
http://finzi.psych.upenn.edu/R/Rhelp02a/archive/33097.html
R equivalent of Splus peaks() function?
The peaks function there has worked well for me on a couple of projects, but
some code using "peaks" failed today, which had worked fine in the past.
I was looking for a peak in a test case that was a sine curve over one
2003 Jan 16
7
X11 device now needs to be explicitly started?
_
platform i686-pc-linux-gnu
arch i686
os linux-gnu
system i686, linux-gnu
status
major 1
minor 6.2
year 2003
month 01
day 10
language R
>
Until this version, I've not had to explicitly start the x11 device.
Now,
2001 May 29
2
Using "R" to find peaks in sampled data
This is probably a trivial question, but I did
not see it in the FAQs. Perhaps I simply need
to be pointed to some URLs.
In any case, I have some sampled data that has peaks,
and I would like to extract peak height, location, and
width, according to almost any statistical model.
Gaussian would seem to make the most sense.
There can also be "steps" increasing the amplitude
over a
2003 Nov 26
5
multiple peaks in data frame
Hello, it wanted to know how I can extract of a dates frame the values
peaks according to an interval that I
establish. For example if dates are:
1 23
2 4
3 56
4 7
5 99
6 33
extract the date i wanted to divide into intervals of 2 an
d to take alone the numbers 23, 56 and 99 of those 3 intervals. Thanks
Ruben
2004 Jan 14
1
R equivalent of Splus peaks() function?
If there something available in R that has the
functionality of the S-PLUS peaks() function?
Thanks,
Mirka
2007 Oct 13
2
How to identify the two largest peaks in a trimodal distribution
Hello all
I'm trying to do a simulation that involves identifying the minimum
point between two peaks of a (usually) bimodal distribution. I can do
this easily if there are only two peaks:
CnBdens<-density(Ys/Xs) #probability density function for ratio of Ys
to Xs
for(p in 1:512) ifelse(CnBdens$y[p]>CnBdens$y[p-1],peak1<-p,break)
#identifies first peak in probability
2005 Nov 23
5
finding peaks in a simple dataset with R
I've been asked in private,
(and am replying BCC to the asker),
>> I saw your post on the R-help archives page about the possibility of
>> porting a function from S-Plus called peaks() to R. I am looking for
>> some way to locate peaks in a simple x,y data set, and thought that R
>> might be the way to go.
"of course" it is the way to go, don't get
2001 Jun 15
1
R equivalent for Splus "peaks"
Hi, all.
Does anyone have an equivalent to Splus "peaks", which finds local maxima
(with locality defined by a parameter "span")? I thought I'd check
whether anyone has done it already before trying to put something together
myself.
Thanks,
Matt Wiener
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