clone: Cloning ff and ram objects

Description

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

Usage

clone(x, …)
# S3 method for 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
, …)
# S3 method for list
clone(x, …)
# S3 method for default
clone(x, …)

Arguments

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 1:length(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

Value

an ff or ram object

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.

Examples

Run this code

# NOT RUN {
  x <- ff(letters, levels=letters)
  y <- clone(x, length=52)
  rm(x,y); gc()
# }

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