ff: clone.ff – R documentation

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clone.ff

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` `vmode`s, 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

Examples

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

ff

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

v4.0.4

GPL-2 | GPL-3 | file LICENSE

Authors

Daniel Adler [aut], Christian Gläser [aut], Oleg Nenadic [aut], Jens Oehlschlägel [aut, cre], Martijn Schuemie [aut], Walter Zucchini [aut]

Initial release

2020-10-13