similar to: Suggestions: Terminology & Pkgs for following spectra over time

Displaying 20 results from an estimated 2000 matches similar to: "Suggestions: Terminology & Pkgs for following spectra over time"

2012 Apr 27
1
Hyperspec package: need to change spectra names in a stacked plot
Hi all, I need to insert the name of spectra in a stacked plot obtained with hyperspec. I use this command plot(spectra [c(-1:-4, -6:-8, -10:-12, -14:-16)], stacked = T) but, in this way R draw nameless spectra on the Y axis. How can I solve the problem? Thank you for any suggestion. Best regards, Roberto -- View this message in context:
2006 Jul 11
3
least square fit with non-negativity constraints for absorption spectra fitting
I would really appreciate it if someone can give suggestions on how to do spectra fitting in R using ordinary least square fitting and non-negativity constraints. The lm() function works well for ordinary least square fitting, but how to specify non-negativity constraints? It wouldn't make sense if the fitting coefficients coming out as negative in absorption spectra deconvolution. Thanks.
2007 Feb 01
3
Lining up x-y datasets based on values of x
Hi, I was wondering if there is a direct approach for lining up 2-column matrices according to the values of the first column. An example and a brute-force approach is given below: x <- cbind(1:10, runif(10)) y <- cbind(5:14, runif(10)) z <- cbind((-4):5, runif(10)) xx <- seq( min(c(x[,1],y[,1],z[,1])), max(c(x[,1],y[,1],z[,1])), 1) w <- cbind(xx, matrix(rep(0, 3*length(xx)),
2009 Feb 17
2
Chromatogram deconvolution and peak matching
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
2011 Mar 30
0
Package ChemoSpec 1.46 Now Available on CRAN
I'm pleased to announce that the ChemoSpec package is available on CRAN for the first time (as version 1.46-4). ChemoSpec is a collection of functions for plotting spectra (NMR, IR etc) and carrying out various forms of top-down exploratory data analysis, such as HCA, PCA and model-based clustering. The design permits comparison of data from samples which fall into groups such as
2011 Mar 30
0
Package ChemoSpec 1.46 Now Available on CRAN
I'm pleased to announce that the ChemoSpec package is available on CRAN for the first time (as version 1.46-4). ChemoSpec is a collection of functions for plotting spectra (NMR, IR etc) and carrying out various forms of top-down exploratory data analysis, such as HCA, PCA and model-based clustering. The design permits comparison of data from samples which fall into groups such as
2009 Nov 16
4
Where are usages like "== 2L" documented?
Gurus: I keep seeing other people?s code that contain ideas like If (x == 2L) X[-1L] X - 1L I have some idea of what?s going on, but where is the use of concepts like ?2L? documented? Thanks, Bryan ************* Bryan Hanson Acting Chair Professor of Chemistry & Biochemistry DePauw University, Greencastle IN USA
2008 Mar 30
2
Definition of "wrapper"?
I think I more or less understand what a ?wrapper? is, but I?d like to hear how more experienced R users define it, and especially I'd like to know if there is a formal definition. In my reading, it seems like there are a fairly wide range of meanings, but they are all conceptually similar. I've looked in a couple of the classic R texts, the extensions and developers' manuals, and R
2010 Nov 29
3
Replacing several rows of a matrix at once
Hello Folks. This must be a silly question with a (not) obvious (to me) answer. Consider this: tmp <- matrix(1:200, nrow = 20) vec <- 300:309 tmp[9,] <- vec # replacing one row works fine p <- c(3, 11, 17) tmp[p,] <- vec # replacing multple rows pastes the values down a column and recycles vec. What I want to do is replace multiple rows simultaneously at once. I suppose I can
2020 Oct 19
1
spec.pgram returns different spectra when fast=TRUE and the number of samples is odd
Dear all, This is potentially a bug in spec.pgram, when the number of samples is odd,spec.pgramreturns a different result withfast = TRUE, the example below contains the two varieties with a reference spectrum calculated manually. the number of returned spectra is also larger (50 compared to 49) whenfast = TRUE x <- rnorm( 99 ) plot(spec.pgram(x, taper = 0 , detrend = FALSE , plot =
2010 Mar 14
2
Why doesn't vec[-real.number] give an error or warning? Kids do the darndest things!
Hi all... My students were conflating grepping for a value in a vector to get the index, and then removing it with [-index], for instance like this: set.seed(17) v <- rnorm(20) s <- v[-1.18] They were trying to remove the 12th value in v, which is -1.18 or so. But the result is, as documented in ?Extract, to coerce 1.18 to the next lowest integer, and remove the 1st value of v, not the
2009 Sep 07
1
xyplot {lattice} are different types possible for each panel?
Hello R Folks... Using the example below, I¹d like two of the panels to be plotted with type = ³p² but the third to be done with type = ³h². I can¹t use type = c(³p², ³p², ³h²) because this syntax applies all given types to every panel. I don¹t think I can use groups and distribute.type because these are intended for different styles of plotting within a single panel. As you can see, I tried
2009 Dec 29
1
ggplot2, building a simple formula interface
I?m trying to build a simple formula interface to work with a function using ggplot2. The following scheme ?works? up until the plot(p) request, at which point there are complaints about xlim?s and a blank graphics window. Looking at str(p) I do see the limits are NULL, plus layer 1 claims to have an empty data frame (but df is reproduced correctly). I'm sure I'm missing something really
2009 Sep 16
2
Teasing out logrank differences *between* groups using survdiff or something else?
R Folk: Please forgive what I'm sure is a fairly na?ve question; I hope it's clear. A colleague and I have been doing a really simple one-off survival analysis, but this is an area with which we are not very familiar, we just happen to have gathered some data that needs this type of analysis. We've done quite a bit of reading, but answers escape us, even though the question below
2009 Aug 11
1
Selecting/Accessing the last vector in a list of a list of data.frames
Hello Again R Folks: I?m trying to clean up some code. Suppose I have an object like this: > str(test) List of 2 $ G:List of 2 ..$ cls:'data.frame': 101 obs. of 2 variables: .. ..$ V1: num [1:101] -0.0019 -0.0019 -0.00189 -0.00188 -0.00186 ... .. ..$ V2: num [1:101] 0.000206 0.000247 0.000288 0.000329 0.000371 ... ..$ rob:'data.frame': 101 obs. of 2
2009 Oct 23
1
ggplot2: stat_bin ..count.. with geom_text when NA is present
One for the ggplot2 gurus... I have a function which makes a plot just fine if the response vector (res in the example; fac1 is a factor) has no NA in it. It plots the data, then makes a little annotation at the bottom with the data counts using: p <- p + geom_text(aes(x = fac1, y = min(res) - 0.1 * diff(range(res)), label = paste("n = ", ..count.. , sep =
2010 Jul 12
2
findInterval and data resolution
Hello Wise Ones... I need a clever way around a problem with findInterval. Consider: vec1 <- 1:10 vec2 <- seq(1, 10, by = 0.1) x1 <- c(2:3) a1 <- findInterval(x1, vec1); a1 # example 1 a2 <- findInterval(x1, vec2); a2 # example 2 In the problem I'm working on, vec* may be either integer or numeric, like vec1 and vec2. I need to remove one or more sections of this vector;
2011 May 20
3
Downloading a csv from Dropbox using the shareable link
Hello Kindred R Spirits... I'm trying to get a file (csv) from Dropbox using their shareable link concept. They issue a short URL that goes to a web page where you see a button that says "Download File". They don't really give you the URL of the file itself, just this page. Is there a way to coax R into getting such a file? I don't even really want the file per
2009 Aug 10
3
Need Advice: Considering Converting a Package from S3 to S4
Hello R Folks... Not a technical question, but I need some advice and perspective. I?ve got a set of functions I?m planning to put together into a package. The main hunk of data that gets used by different functions is currently an S3 list. I?ve been reading about S4 objects, and I see the (numerous) advantages of them. I have seen the recommendation that all new packages be done with S4.
2009 Dec 07
1
rgl keyboard shortcut for translation on Mac?
Hello Everyone. I?m on a Mac, using rgl. Thanks to all the developers and maintainers on it! If I drag the mouse, I can rotate the view, if I hold down the option key or the ctrl key and drag, I get scaling (though at times I seem to alter the perspective?). Adding the shift key doesn't seem to modify anything. So, what I can't find is a key combination that translates the object.