similar to: Variance explained by cluster analysis

Hi, I went ahead and implemented something. However: - I cannot garantie it gives correct results since, unfortunately, the data used in Syrjala 1996 is not published along with the paper. To avoid mistakes, I started by coding things in a fast and simple way and then tried to optimize the code. At least all versions given the same results. - As expected, the test is still quite slow

Dear R people, I need to do some work with clustering, but know next to nothing about it at present. R has (at least) three clustering packages, cluster, mclust, cclust. I was wondering if someone can direct me to some good books where I could find documentation and background on the functions in these packages. The html help in these packages lists the following as references. Can people

Dear All, I am attempting to use the FANNY fuzzy clustering function in R (Kaufman & Rousseeuw, 1990), found in the "cluster" package. I have run into a variety of difficulties; the two most crucial difficulties are enumerated below. 1. Where is the 'm' parameter in FANNY? In _Finding Groups in Data: An Introduction to Cluster Analysis_ (1990) by Kaufman & Rousseeuw,

Hi, I'm trying to use a similarity matrix (triangular) as input for pam() or fanny() clustering algorithms. The problem is that this algorithms can only accept a dissimilarity matrix, normally generated by daisy(). However, daisy only accept 'data matrix or dataframe. Dissimilarities will be computed between the rows of x'. Is there any way to say to that your data are already a

Hello everyone, I am (happily) using ggplot2 for all my plotting now and I wondered is there is an easy way to specify xlim and ylim somewhere when using the ggplot syntax, as opposed to the qplot syntax. Eg. qplot(data=mtcars,y=wt, x=qsec,xlim=c(0,30)) <-> ggplot(mtcars, aes(y=wt, x=qsec)) + geom_point() + ??? Indeed the ggplot syntax is in general more flexible and powerful and

Hello everybody, This is probably a classic but I cannot find an answer to this on the mailing list (i.e. with a google search restricted to the mailing list archive). Setting: par(new=T) plot(x,y) works but plot(x,y,new=T) doesn't while it is said in plot's help that ... arguments are passed to par. What am I missing? JiHO --- http://jo.irisson.free.fr/

Hello, I would like to use my own dissimilarity matrix in a PAM clustering with method "pam" (cluster package) instead of a dissimilarity matrix created by daisy. I read data from a file containing the dissimilarity values using "read.csv". This creates a matrix (alternatively: an array or vector) which is not accepted by "pam": A call

Hi everyone, Hi ggplot users in particular, ggplot makes it very easy to plot things given their names when you use it interactively (and therefore can provide the names of the columns). qplot(x,foo,data=A) where A has columns (x,y,foo,bar) for example but I would like to use this from inside a function to which the name of the column is given. I cannot find an elegant way to make this

Hello everyone, I have two data.frames that look like calib: place zoom scale left 0.65 8 left 0.80 5.6 left 1.20 3 right 0.65 8.4 right 0.80 6 right 1.20 2.9 X: ... place zoom .... ... left 0.80 .... ... left 1.20 .... ... right 0.65 .... ... NA NA .... ... right 0.8 .... ... left 1.20 .... and I want to get the corresponding values of 'scale' in a new column

Hello everyone, A recent (in 2.5 I suspect) change in R is giving me trouble. I want to apply a function (tolower) to all the columns of a data.frame and get a data.frame in return. Currently, on a data.frame, both apply (for arrays) and lapply (for lists) work, but each returns its native class (resp. matrix and list): apply(mydat,2,tolower) # gives a matrix lapply(mydat,tolower) # gives

Hello all, I discovered that the pdf device uses fonts to represent "points" symbols (as in plot(...,type="p",...) ). Namely it uses ZapfDingbats with symbol U+25cf. This can lead to problems when the font is not available, or available in another version (such as points being replaced by other symbols, or worst: slightly displaced). Furthermore, it also causes

Hello all, I am sure I am missing something obvious but I cannot find the function I am looking for. I have a data frame with three columns: X, Y and Z, with X and Y being grid coordinates and Z the value associated with these coordinates. I want to transform this data frame in a matrix of Z values, on the grid defined by X and Y (and, as a plus, fill the X.Y combinations which do no

Hello eveybody, I am studying the vertical distribution of plankton and want to study its variations relatively to several factors (time of day, species, water column structure etc.). So my data is special in that, at each sampling site (each observation), I don't have *one* number, I have *several* numbers (abundance of organisms in each depth bin, I sample 5 depth bins) which

Hi everyone, Hi Hadley, I am a heavy user of coord_equal() in ggplot2 since most of my data is spatial, on x,y coordinates. Everything works. However by enforcing an aspect ratio of 1 for the plotting region, coord_equal() usually wastes a lot of space if the region of interest is not a perfect square. For example: x=runif(10) a=data.frame(x=x*3,y=x) ggplot(data=a, aes(x=x,y=y)) +

Dear List, I am trying to get R's terminal output to a file and to the terminal at the same time, so that I can walk through some tests and keep a log concurrently. The function 'sink' with the option split=TRUE seems to do just that. It works fine for most output but for objects of class htest, the terminal output is incomplete (the lines are there but empty). Here is an

Hello, I am facing a problem with lapply which I ''''think''' may be a bug. This is the most basic function in which I can reproduce it: myfun <- function() { foo = data.frame(1:10,10:1) foos = list(foo) fooCollumn=2 cFoo = lapply(foos,subset,select=fooCollumn) return(cFoo) } I am building a list of dataframes, in each of which I want to keep only column

Hello everyone, I often create some local "libraries" of functions (.R files with only functions in them) that I latter call. In scripts that call a function from such library, I would like to be able to test whether the function is already known in the namespace and, only if it is not, source the library file. I.e. what `require` does for packages, I want to do with my local

Dear Lists, At several stations distributed regularly in space[1], we sampled repeatedly (4 times) the abundance of organisms and measured environmental parameters. I now want to compare the spatial distribution of various species (and test wether they differ or not), or to compare the distribution of a particular organism with the distribution of some environmental variable.

Hello everyone (and Hadley in particular), I often need to plot data from multiple datasets on the same graph. A common example is when mapping some values: I want to plot the underlying map and then add the points. I currently do it with base graphics, by recording the maximum region in which my map+point will fit, plotting both with these xlim and ylim parameters, adding par (new=T)

Hello everyone, I've been advised to use merge to extract information from two data.frames with a number of common columns, but I cannot get a grasp on how it sorts the result. With sort=FALSE, I would expect it to give the result back sorted exactly as the input was but it seems it is not always the case, especially when there are repeats in the input. For example: > a =