clone.ff: Cloning ff and ram objects

In ff: Memory-Efficient Storage of Large Data on Disk and Fast Access Functions

Cloning ff and ram objects

Description

clone physically duplicates ff (and ram) objects and can additionally change some features, e.g. length.

Usage

## S3 method for class 'ff'
clone(x
, initdata = x
, length = NULL
, levels = NULL
, ordered = NULL
, dim = NULL
, dimorder = NULL
, bydim = NULL
, symmetric = NULL
, fixdiag = NULL
, names = NULL
, dimnames = NULL
, ramclass = NULL
, ramattribs = NULL
, vmode = NULL
, update  = NULL
, pattern = NULL
, filename = NULL
, overwrite = FALSE
, pagesize = NULL
, caching = NULL
, finalizer = NULL
, finonexit = NULL
, FF_RETURN = NULL
, BATCHSIZE = .Machine$integer.max
, BATCHBYTES = getOption("ffbatchbytes")
, VERBOSE = FALSE
, ...)

Arguments

x	x
initdata	scalar or vector of the .vimplemented vmodes, recycled if needed, default 0, see also as.vmode and vector.vmode
length	optional vector length of the object (default: derive from 'initdata' or 'dim'), see length.ff
levels	optional character vector of levels if (in this case initdata must be composed of these) (default: derive from initdata)
ordered	indicate whether the levels are ordered (TRUE) or non-ordered factor (FALSE, default)
dim	optional array dim, see dim.ff and array
dimorder	physical layout (default seq_along(dim)), see dimorder and aperm
bydim	dimorder by which to interpret the 'initdata', generalization of the 'byrow' paramter in matrix
symmetric	extended feature: TRUE creates symmetric matrix (default FALSE)
fixdiag	extended feature: non-NULL scalar requires fixed diagonal for symmetric matrix (default NULL is free diagonal)
names	see names
dimnames	NOT taken from initdata, see dimnames
ramclass	class attribute attached when moving all or parts of this ff into ram, see ramclass
ramattribs	additional attributes attached when moving all or parts of this ff into ram, see ramattribs
vmode	virtual storage mode (default: derive from 'initdata'), see vmode and as.vmode
update	set to FALSE to avoid updating with 'initdata' (default TRUE) (used by ffdf)
pattern	root pattern for automatic ff filename creation (default "ff"), see also physical
filename	ff filename (default tmpfile with 'pattern' prefix), see also physical
overwrite	set to TRUE to allow overwriting existing files (default FALSE)
pagesize	pagesize in bytes for the memory mapping (default from getOptions("ffpagesize") initialized by getdefaultpagesize), see also physical
caching	caching scheme for the backend, currently 'mmnoflush' or 'mmeachflush' (flush mmpages at each swap, default from getOptions("ffcaching") initialized with 'memorymap'), see also physical
finalizer	name of finalizer function called when ff object is removed, (default "deleteIfOpen" from getOptions("fffinalizer"))), standard finalizers are close.ff, delete.ff and deleteIfOpen.ff, see also reg.finalizer
finonexit	logical scalar determining whether finalizer is also called when R is closed via q, (default TRUE from getOptions("fffinonexit"))
FF_RETURN	logical scalar or ff object to be used. The default NULL creates a ff or ram clone, TRUE returns a ff clone, FALSE returns a ram clone. Handing over an ff object here uses this or stops if not ffsuitable
BATCHSIZE	integer scalar limiting the number of elements to be processed in update.ff when length(initdata)>1, default from getOption("ffbatchsize")
BATCHBYTES	integer scalar limiting the number of bytes to be processed in update.ff when length(initdata)>1, default from getOption("ffbatchbytes"), see also .rambytes
VERBOSE	set to TRUE for verbosing in update.ff when length(initdata)>1, default FALSE
...	further arguments to the generic

Details

clone is generic. clone.ff is the workhorse behind as.ram and as.ff. For creating the desired object it calls ff which calls update for initialization.

Value

an ff or ram object

Author(s)

Jens Oehlschlägel

See Also

ff, update, as.ram, as.ff

Examples

  x <- ff(letters, levels=letters)
  y <- clone(x, length=52)
  rm(x,y); gc()

ff documentation built on Sept. 30, 2024, 9:38 a.m.