Dear R-listers, 

I  have been using Snowfall (version 1.84) for parallel computing on a quad-PC running Windows 7 for a month or so without much problem. I started having problems runnnig R with Snowfall over our network when a new Novell client was installed for Windows 7. I experinenced network mapping problem with this new client. Our network colleague provided a fix which worked but a little unstable. So I decided to copy every file that I need from the networked drive to my local drive and ran R locally instead. I had no problem with R running locally for many long R jobs until this morning when Snowfall has stopped working completely. PLease note my R is installed locally. 

Snowfall has been complaining about not being able to open a connection. I am not sure what it means as I am not a network person. Any advice will be very welcome. Many thanks in advance.  See output and the error message below. 

Best wishes, 
Edmond 

************** OUTPUT AND ERROR MESSAGE *******************
 > # initialize Snowfall parameters
> sfInit(parallel=TRUE, cpus=2, type="SOCK") 
snowfall 1.84 initialized (using snow 0.3-3): parallel execution on 2 CPUs.

> # perform parallel calculations 
> rr <- list() 
> date()
[1] "Thu Jun 24 09:17:56 2010"
> el.time <- system.time(
+ 
+ for (i in 1:(n.sims/everyout)) {
+  loop.start <- i*everyout -(everyout-1) 
+  loop.end <- i*everyout 
+  print(paste("loop.start = ",loop.start)) 
+  print(paste("loop.end = ",loop.end)) 
+ 
+  rr[[i]] <- sfClusterApplyLB(loop.start:loop.end,wrapper1,reps) 
+  a<-rr[[i]]
+  save(a,file=paste("rr_",i,".RData",sep=""))
+ }
+ )
[1] "loop.start =  1"
[1] "loop.end =  10"
Error in checkForRemoteErrors(val) : 
  10 nodes produced errors; first error: cannot open the connection
Timing stopped at: 0 0 0.06
************** END OF OUTPUT AND ERROR MESSAGE *******************


++++++++++++++++++++++++++++++++++
Edmond Ng, MSc CStat
Lecturer in Medical Statistics
Department of Health Services Research and Policy
Faculty of Public Health and Policy
London School of Hygiene and Tropical Medicine 
15-17 Tavistock Place
London WC1H 9SH, UK 
Tel: +44 (0)20 7927 2366 (direct line: ext 2065)  Fax: +44 (0)20 7927 2701
Website: http://www.lshtm.ac.uk/hrsu
++++++++++++++++++++++++++++++++++

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