R help - May 2011 - Problems saving ff objects

Dear list,


I am trying to understand and use the ff package. As I had some problems saving
some ff objects, and as I did not fully manage to understand the whole concept
of *.ff, *.ffData and *.RData with the help of the documentation, I tried to
reproduce the examples from the help of ffsave.

When I ran, however : (copied from the help)

 message("let's create some ff objects")
  n <- 8e3
  a <- ff(sample(n, n, TRUE), vmode="integer", length=n,
filename="d:/tmp/a.ff")
  b <- ff(sample(255, n, TRUE), vmode="ubyte", length=n,
filename="d:/tmp/b.ff")
  x <- ff(sample(255, n, TRUE), vmode="ubyte", length=n,
filename="d:/tmp/x.ff")
  y <- ff(sample(255, n, TRUE), vmode="ubyte", length=n,
filename="d:/tmp/y.ff")
  z <- ff(sample(255, n, TRUE), vmode="ubyte", length=n,
filename="d:/tmp/z.ff")
  df <- ffdf(x=x, y=y, z=z)
  rm(x,y,z)

  message("save all of them")
  ffsave.image("d:/tmp/x")

I get:

Error in ffsave(list = ls(envir = .GlobalEnv, all.names = TRUE), file = outfile,
:
  the previous files do not match the rootpath (case sensitive)


Whats wrong here? Should this not be working as I did not change anything in the
code?



Cheers
Jannis

> sessionInfo()
R version 2.12.0 (2010-10-15)
Platform: i386-pc-mingw32/i386 (32-bit)

locale:
[1] LC_COLLATE=English_United States.1252 
[2] LC_CTYPE=English_United States.1252   
[3] LC_MONETARY=English_United States.1252
[4] LC_NUMERIC=C                          
[5] LC_TIME=English_United States.1252    

attached base packages:
[1] tools     stats     graphics  grDevices utils     datasets  methods  
[8] base     

other attached packages:
[1] ff_2.2-2   bit_1.1-7  rj_0.5.2-1

loaded via a namespace (and not attached):
[1] rJava_0.8-8

Just did some more testing.....May the problem be due to the fact that I am
using a windows machine? I just ran the same code on a Linux machine and
everything worked fine.

If windows (or the file system of the disk) caused the problem, is there any way
to resolve it? I know that using Linux would be a better choice ;-) but
unfortunatley this in no option at the moment....


Best
Jannis

--- Jannis <bt_jannis at yahoo.de> schrieb am Mi, 4.5.2011:
> Von: Jannis <bt_jannis at yahoo.de>
> Betreff: [R] Problems saving ff objects
> An: r-help at r-project.org
> Datum: Mittwoch, 4. Mai, 2011 13:17 Uhr
> Dear list,
> 
> 
> I am trying to understand and use the ff package. As I had
> some problems saving some ff objects, and as I did not fully
> manage to understand the whole concept of *.ff, *.ffData and
> *.RData with the help of the documentation, I tried to
> reproduce the examples from the help of ffsave.
> 
> When I ran, however : (copied from the help)
> 
>  message("let's create some ff objects")
> ? n <- 8e3
> ? a <- ff(sample(n, n, TRUE), vmode="integer",
> length=n, filename="d:/tmp/a.ff")
> ? b <- ff(sample(255, n, TRUE), vmode="ubyte",
> length=n, filename="d:/tmp/b.ff")
> ? x <- ff(sample(255, n, TRUE), vmode="ubyte",
> length=n, filename="d:/tmp/x.ff")
> ? y <- ff(sample(255, n, TRUE), vmode="ubyte",
> length=n, filename="d:/tmp/y.ff")
> ? z <- ff(sample(255, n, TRUE), vmode="ubyte",
> length=n, filename="d:/tmp/z.ff")
> ? df <- ffdf(x=x, y=y, z=z)
> ? rm(x,y,z)
> 
> ? message("save all of them")
> ? ffsave.image("d:/tmp/x")
> 
> I get:
> 
> Error in ffsave(list = ls(envir = .GlobalEnv, all.names > TRUE), file =
outfile,? :
> ? the previous files do not match the rootpath (case
> sensitive)
> 
> 
> Whats wrong here? Should this not be working as I did not
> change anything in the code?
> 
> 
> 
> Cheers
> Jannis
> 
> 
> > sessionInfo()
> R version 2.12.0 (2010-10-15)
> Platform: i386-pc-mingw32/i386 (32-bit)
> 
> locale:
> [1] LC_COLLATE=English_United States.1252 
> [2] LC_CTYPE=English_United States.1252???
> [3] LC_MONETARY=English_United States.1252
> [4] LC_NUMERIC=C? ? ? ? ? ?
> ? ? ? ? ? ? ? 
> [5] LC_TIME=English_United States.1252? ? 
> 
> attached base packages:
> [1] tools? ???stats?
> ???graphics? grDevices utils?
> ???datasets? methods? 
> [8] base? ???
> 
> other attached packages:
> [1] ff_2.2-2???bit_1.1-7? rj_0.5.2-1
> 
> loaded via a namespace (and not attached):
> [1] rJava_0.8-8
> 
> 
> 
> 
> ______________________________________________
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http://www.R-project.org/posting-guide.html
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>