similar to: Using "R" to find peaks in sampled data

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

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

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

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

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

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

I have a seasonal time series. I want to calculate the annual mean value of the time series at its peak (say the mean of the three values before the peak, the peak, and the three values after the peak). The peak of the time series might change cycle slightly from year to year. # E.g., nPts <- 254 foo <- sin((2 * pi * 1/24) * 1:nPts) foo <- foo + rnorm(nPts, 0, 0.05) bar <- ts(foo,

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

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 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read

Hi All, I apologise if this question has been answered before, but my background is a little different from most people using R, and the language we use seems to be different! I am trying to analyse some nuclear physics data, which consists of an ensemble of "energy" readings in a detector that, when binned, form a number of Gaussian shaped peaks superimposed on a varying background

Hi I went through some extensive search to find suitable method (package, function) to fit multiple peaks. The best I found is ALS package but it requires rather complicated input structure probably resulting from GC-MS experimental data and seems to be an overkill to my problem. I have basically simple two column data frame with columns time and sig dput(temp) structure(list(time = c(33, 34,

I'm sure there must be various peak-finding algorithms out there. Not knowing of any, I have written one myself*, but I thought I'd ask to see what's out there. Basically, I have a 2-dimensional data set and I want to identify local peaks in the data, while ignoring "trivial" peaks. My naive algorithm first identifies every peak and valley (point of inflection change

Dear useRs, I have a curve which is a mixture of Gaussian curves (for example UV emission or absorption spectrum). Do you have any suggestions how to implement searching for optimal set of Gaussian peaks to fit the curve? I know that it is very complex problem, but maybe it is a possibility to do it? First supposement is to use a nls() with very large functions, and compare AIC value, but it is

Hi, I was wondering if anyone knows of a package that contains the ability for peak/valley detection. Here is an example of what I'm looking for, only problem is that it's written in Matlab. http://www.billauer.co.il/peakdet.html Thanks for any help in advance. -Joe

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

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

Grrr ... new trial with code here: http://pastebin.com/RjHNNG9J Maybe the amount of inline-code prevented posting? Hello, I am writing a simple peak detector and it works quite well ... however there's one special case below, that I can't get my head wrapped around ... the problem is in the "Deal with not fully qualified peaks at the sequence extremes" section, but I cannot

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"

Hi, I am sorry for this question, but I am trying to speed up an application.... I will need to fit many x-y data sets (input from text files) to 4-parameter Pseudo-Voigt peak function. Until now I used SigmaPlot macro to do it (enclosed just in case...) peaksign(q) = if(total(q)>q[1], 1, -1) xatymin(q,r) = xatymax(q,max(r)-r) [Parameters] a = if(peaksign(y)>0, max(y), min(y))

Hi, I'm trying to match peaks between chromatographic runs. I'm able to match peaks when they are chromatographed with the same method, but not when there are different methods are used and spectra comes in to play. While searching I found the ALS package which should be usefull for my application, but I couldn't figure it out. I made some dummy chroms with R, which mimic my actual