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Given a matrix B, where B=A'A, how can I find A? In other words, if I have a matrix B which I know is another matrix A times its transpose, can I find matrix A? Thanks, Mike

...may need some development packages? What is a good place to find these packages? I am running R version 2.5.1 on a Linux machine running Redhat Enterprise 3. Let me know if you need any more info on the operating system and if there are any ideas on how to resolve these issues. Thanks, Michael Gormley [[alternative HTML version deleted]]

I have created a data frame using the read.table command. I want to be able to access the rows by the row name, or a vector of row names. I know that you can access columns by using the data.frame.name$col.name. Is there a way to access row names in a similar manner? [[alternative HTML version deleted]]

I am trying to preprocess a large dataset of affymetrix data. Creating an affybatch is not possible with the computer I am running it on, so I have used the justRMA command to run RMA. I have read the affy document describing the justRMA command and the help documentation but I am unclear as to whether this command uses median polish after normalization. I assume this is the case but would like

The offset argument used in glm and other functions seems to have been removed from the argument list for coxph. I am wondering if there is a reason for this and if there is a possible work-around in order to produce a cox-ph object without fitting coefficients? Thanks, Mike

Hi all. I have an issue that I cannot resolve. I am trying to read in lots of data that are stored in xml files. But after I read them in and copy the relevant data, then remove the document etc, it doesn't free up the memory. When I monitor it in windows task manager the memory usage just climbs with each iteration until R crashes. I can replicate the problem with the small example:

I am trying to run a monte carlo process using snow with a MPI cluster. I have ~thirty processors to run the algorithm on and I want to run it 5000 times and take the average of the output. A very simple way to do this is to divide 5000 by the number of processors to get a number n and tell each processor to run the algorithm n times. I realize there are more efficient ways to manage the

...0 (0x0) smb_vwv[ 3]= 9 (0x9) smb_bcc=89 SPNEGO login failed: Logon failure session setup failed: NT_STATUS_LOGON_FAILURE ====================================================== any help appreciated many thanks ________________________________________________________________________ Clinton Gormley clinton@traveljury.com www.TravelJury.com - For travellers, By travellers