search for: vanderkogel

Hi all, I'm currently working with a dataset that has quite a few missing values and after some investigation I figured that multiple imputation is probably the best solution to handle the missing data in my case. I found several references to functions in S-Plus that perform multiple imputation (NORM, CAT, MIX, PAN). Does R have corresponding functions? I searched the archives but was not

Hi all, I am running a series of experiments where after manipulating my data I run several clustering algorithms (agnes, diana and a clustering method of my own) on the data. I wanted to determine which clustering method did the best job, so therefore I had defined my own quality measure using two criteria: compactness of the data within the clusters themselves and the amount of seperation

Hi all, I was wondering whether it is possible to plot math functions, for example sin, cos or a Gaussian type function, in R, and if so, how to do it. I have been searching through the archives and the R manual but had no luck in finding any hints on how to go about this. Any help is much appreciated! Thanks, Jonck

Hi all, I have (yet another) question about a function in R. What I would like to do is test for the presence of a certain value in a vector, and have the positions that this value is at returned to me. For example, let's say I have a vector: x <- c(1,1,2,2,3,3,4,4) Now I would like a function that would return positions 3 and 4 should I test for the value "2". Or 5 and 6

...ersity of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272860 (secr) Oxford OX1 3TG, UK Fax: +44 1865 272595 ------------------------------ Message: 8 Date: Thu, 26 Jun 2003 14:21:05 +0200 From: Jonck van der Kogel <jonck at vanderkogel.net> Subject: [R] GeneSOM viewer To: r-help at stat.math.ethz.ch Message-ID: <A8E39270-A7D0-11D7-85E0-0005026E2B43 at vanderkogel.net> Content-Type: text/plain; charset=US-ASCII; format=flowed Hi all, Recently I have written a small application, SOMviewer, that is able to graphically dis...

Hi all, I have a question about the SOM routine. You can either supply the initial representatives for the lattice yourself or else they are chosen randomly from the dataset. Is it possible to pass the random-seed as an argument somehow, when choosing the random initialisation of the lattice? As it is now, each time I run a SOM on a dataset with the same settings the resulting SOM will still

Hi all, I am having a bit of trouble with the array structure of R. What I want to do is dynamically add/remove elements to an array. For example: Let's say I have created an array: > myArray <- array(c(3,8), dim=c(1,2)) > myArray [,1] [,2] [1,] 3 8 And I now want to, for example, push an element (5,6) on to this array so it will read: [,1] [,2] [1,] 3 8

Hello everyone, I'm new to this list, so let me introduce myself: my name is Jonck van der Kogel and I am a graduate student at the Erasmus University of Rotterdam. I am currently working on my thesis which is on the use of artificial intelligence for large data-sets. To do an analysis of a certain data-set I want to use Kohonen's SOM algorithm. However, as I understand it, the SOM

Hi all, A short while ago I asked a question about multiple imputation and I got several helpful replies, thanks! I have untill now tried to use the packages mice and norm but both give me errors however. mice does not even run to start with and gives me the following error right away: iter imp variable 1 1 Liquidity.ratioError in chol((v + t(v))/2) : the leading minor of order 1 is not