Message-ID: <1429395252@web.de>
Date: 2009-11-27T16:32:17Z
From: Jens Oehlschlägel
Subject: questions on the ff package
> I wonder how efficiently it is to do the following command on a frequent basis.
> nrow(matFF) <- nrow(matFF)+1
Obviously there is overhead (closing file, enlarging file, openeing file).
I recommend you measure yourself whether this is acceptable for you.
> no large file copying is needed each time the nrow is changed?
With a decent filesystem there is *no* copying from smaller to larger file.
> would you think I can open 2000 large matrices and leave them open or I
need to close each after it is opened and used?
Not tested yet.
I guess the number of open files can be configured when compiling your OS.
Please test and let us know your experience.
Regards
Jens Oehlschl?gel