similar to: element wise opertation between a vector and a list

Hello, I work on large matrices and found something interesting. For multiplication of matrices, the order has a huge influence on computing time when one of them is a sparse matrix. In the below example, M is a full matrix and A is a sparse matrix in a regular matrix class. A %*% M takes much more time than M %*% A; moreover, t(t(M) %*% t(A)) is much faster than A %*% M with same result. I

I want to know how to get trace of product of matrices **faster** when the matrices are really big. Unfortunately the matrices are not symmetric. If anybody know how to get the trace of it, please help me. An example is as below. n <- 2500 a <- matrix(rnorm(n*n),n,n) b <- matrix(rnorm(n*n),n,n) tr1 <- sum(diag(a %*% b)) tr2 <- sum(diag(a %*% b %*% a %*% b)) Thanks, Yongwan Chun

Hello, I was trying to build R from source on Windows XP. I installed software which are mentioned from the follow web page http://www.murdoch-sutherland.com/Rtools/ (Last accessed on Nov. 13th, 2006) . Unfortunately, I got error messages whenever I run 'make all recommended' without modifying 'MkRules' file. I have removed software and reinstalled them several times but I still

Now, I am working with some design matrices. My problem is to set "contrasts" option. Now I want to use "contr.sum" as the option, and it works properly. However, this option sets the last element of a factor as -1. For example, if I have a factor which has 5 elements and want to use the "contr.sum" option, the 5th elements is always set to -1. I want set -1 to other

Dear R users: I have a problem about catch the value from function. I have following two functions (part): fbolus1 <- function() {......... par<-data.frame(Parameter=c("kel","Vd"),Initial=c(0)) check(par) .....} check<-function(par) { if (par[ ,2] <= 0){ cat("\nEnter again (y/n) ?\n\n") ans<-readline() if (ans == "n" ){

Dear All, I have Centos 5.1 and sendmail mail server running for over a year and been workin fine i also use mailscanner + clamav now some remote users have been complaing that the mail sometimes time out i have even tried to stop the mail scanner and jus test my sendmail but the problem exists now i would apprecite if someone cd help me or let me know of a link where i could test the mail

Dear All, I have been using -- shorewall-4.0.14-1 on Centos 5.2 and its been working just great. i would like to monitor shorewall traffic ( i mean the allowed and dropped traffic passing through my firewall )with a browser from any location apprecite if someone could help me or advice me which software or add on utility would do the above. really apprecite thanks nd regards simon

Hi, I am looking for a one-liner code for the following situation say I have a vector r of 0 and 1's, and another vector v of equal length. I want to assign v[i]-1 to v[i] if r[i]=1, for all i. How would I do that using mapply or any other batch processing keywords? thanks. John -- View this message in context:

Dear All, I have 2 server with almost identical configuration nd would like to mirror them bascillay i would like to use it as a firewall. i was thinking of linux HA but could not really find clear examples if it could achive my purpose apprecite if someone can help me of any site with examples on how to mirror 2 centos servers so i one fails the other works perfect thanks and really

Dear All, its a offtopic question but really apprecite if someone would advise n help i have been running a mil server with sendmail and have sbl-xbl.spamhaus.org as my dnsbl. i had other servers which are alredy out now that is relays.ordb.org and dsbl.org have already been out of my sendmail config. any one knows of ny other servers i could add in my sendmail config apprecite ur help

Dear All, i have the following setup CentOS 5 server running as a primary DNS server for a long time and is working perfectly fine the server is on public IP and we have abt 5 zones apart from the reverse n local zone now our sister company have recently setup their own DNS and we are supposed to use it. earlier our cleints were using a host file now on my master dns server in /etc/named.conf

Dear R users, I need to analyze data generated from a partial two-by-two factorial design: two levels for drug A (yes, no), two levels for drug B (yes, no); however, data points are available only for three groups, no drugA/no drugB, yes drugA/no drugB, yes drugA/yes drug B, omitting the fourth group of no drugA/yes drugB. I think we can not investigate interaction between drug A and drug B,

Hi! I have a problem with access to svcctl functions from MMC. It quickly (since 23pre1) shows list of services and statuses, but any opertation ends with "Access denied". On .22pre everything (except very-very slow access) works. It is very critical for me. Can anyone help? /aTan

Dear All, Im sorry for posting this query here but was helpless.. as i am not able to subscribe to sendmail mailing list i have jus installed CentOS 5 and the following software sendmail 8.13 bind 9.3 this machine is used as a primary DNS and out mail server and is been workin perfect we jus have a new domain and i want to have virtual mail hosting on the smae machine for our new domain

David: I believe your response on SO is incorrect. This is a standard OFAT (one factor at a time) design, so that assuming additivity (no interactions), the effects of drugA and drugB can be determined via the model you rejected: For example, if baseline control (no drugs) has a response of 0, drugA has an effect of 1, drugB has an effect of 2, and the effects are additive, with no noise we

Dear All, I am sorry for this post if at all i used the wrong forum but I guess someone out there will be there to advise me and help me out and would be really apprecite and be grateful i have new to xen and has setup my first virtual machine I have a centos 5.5 xen server working perfect and have installed a virtual 2008 server and its working fine . Actually i created the virtual machine in

Hi, I am writing a kernel module which works with netfilter. If a certain condition matches, I want to create a qdisc, a class and a filter inside the kernel module. How can I create qdisc, class, and filter inside the kernel? Thanks, Byung-Gon Chun _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com

Dear ALl, Sorry for my posting here but do apprecite if u guys help me.. I have already CenOS 5 and been used as my Primary DNS and primary sendmail mail server and is working perfectly fine i also have another Centos MAchine being used as my secondary DNS server and been workin fine.. i want to use this machine as my backup mail server and has gone to the DOCS have configured DNS and

Dear All, apprecite ur kind help n advice I have a Centos 5 server running only squid for sometime and its workin great. i am concerned about security so i have a shorewall firewall on the machine runnign squid n works grt now i would like to know the follwing 1) does anyone one know of any good antivirus software i could install on the centos OS squid server so as to scan for viruses so i cd

Hi Bert, I am very sorry to bother you again. For the following question, as you suggested, I posted it in both Biostars website and stackexchange website, so far no reply. I really hope that you can do me a great favor to share your points about how to explain the coefficients for drug A and drug B if run anova model (response variable = drug A + drug B). is it different from running three