R help - Apr 2004 - Weird Error

R-Users,

I hope this is not a uniformed question, but I am a little lost.

I ran into a problem this morning and I was wondering if anyone had
seen it before.  I was trying to summarize each column of a data set
(150,000 rows, ~50mb, so it was a relatively big file) imported from a text
file using the below code;

data.summary <- read.csv("c:/summary.txt", sep="")
data.summary <- as.matrix(data.summary)
my.summary <- function(x){
    return(c(min=min(x),max=max(x), mean=mean(x)))}
apply(data.summary, 2, my.summary)


And I got this weird error that I can not find out anything about?


"Process R unknown signal at Wed Apr 14 08:17:22 2004"


Have you seen anything like this before?  Do you think it is the size of
the dataset that is causing the problem, since the same code works for
25000 rows (~17mb) and gives the correct results (I cross-checked in SAS 
and EXCEL).

I was using R 1.8.0 in Xemacs.


TIA,

Bret Collier

Bret Collier <bacolli at uark.edu> writes:
> R-Users,
> 
> I hope this is not a uniformed question, but I am a little lost.
Don't worry, they all look alike... ;-)
 
> I ran into a problem this morning and I was wondering if anyone had
> seen it before.  I was trying to summarize each column of a data set
> (150,000 rows, ~50mb, so it was a relatively big file) imported from a text
> file using the below code;
> 
> data.summary <- read.csv("c:/summary.txt", sep="")
> data.summary <- as.matrix(data.summary)
> my.summary <- function(x){
>     return(c(min=min(x),max=max(x), mean=mean(x)))}
> apply(data.summary, 2, my.summary)
> 
> 
> And I got this weird error that I can not find out anything about?
> 
> 
> "Process R unknown signal at Wed Apr 14 08:17:22 2004"
> 
> 
> Have you seen anything like this before?  Do you think it is the size of
> the dataset that is causing the problem, since the same code works for
> 25000 rows (~17mb) and gives the correct results (I cross-checked in
> SAS and EXCEL).
Running out of memory and having the OS intervening could give that
kind of message. Or bad RAM. In the first case look up how to set the
memory limits, in the other, change machines to verify.

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907

Bret Collier <bacolli at uark.edu> writes:
> I hope this is not a uniformed question, but I am a little lost.
> 
> I ran into a problem this morning and I was wondering if anyone had
> seen it before.  I was trying to summarize each column of a data set
> (150,000 rows, ~50mb, so it was a relatively big file) imported from a text
> file using the below code;
> 
> data.summary <- read.csv("c:/summary.txt", sep="")
> data.summary <- as.matrix(data.summary)
> my.summary <- function(x){
>     return(c(min=min(x),max=max(x), mean=mean(x)))}
> apply(data.summary, 2, my.summary)
Peter responded about the error.   You may be able to circumvent the
error by using

apply(data.summary, 2, range)

to get the minimum and maximum and 

colMeans(data.summary)

to get the means.  Those are internal functions and will generate less
overhead (and fewer copies) than calls to your own function.