deepcopy: Produces a physical copy of a ``big.matrix''

Description

This is needed to make a duplicate of a big.matrix, with the new copy optionally filebacked.

Usage

deepcopy(
  x,
  cols = NULL,
  rows = NULL,
  y = NULL,
  type = NULL,
  separated = NULL,
  backingfile = NULL,
  backingpath = NULL,
  descriptorfile = NULL,
  binarydescriptor = FALSE,
  shared = options()$bigmemory.default.shared
)

Value

a big.matrix.

Arguments

x: a big.matrix.
cols: possible subset of columns for the deepcopy; could be numeric, named, or logical.
rows: possible subset of rows for the deepcopy; could be numeric, named, or logical.
y: optional destination object (matrix or big.matrix); if not specified, a big.matrix will be created.
type: preferably specified, "integer" for example.
separated: use separated column organization of the data instead of column-major organization; use with caution if the number of columns is large.
backingfile: the root name for the file(s) for the cache of x.
backingpath: the path to the directory containing the file-backing cache.
descriptorfile: we recommend specifying this for file-backing.
binarydescriptor: the flag to specify if the binary RDS format should be used for the backingfile description, for subsequent use with attach.big.matrix; if NULL of FALSE, the dput() file format is used.
shared: TRUE by default, and always TRUE if the big.matrix is file-backed. For a non-filebacked big.matrix, shared=FALSE uses non-shared memory, which can be more stable for large (say, >50\ fail in such cases due to exhausted shared-memory resources in the system.

Details

This is needed to make a duplicate of a big.matrix, because traditional syntax would only copy the object (the pointer to the big.matrix rather than the big.matrix itself). It can also make a copy of only a subset of columns.

Examples

Run this code

x <- as.big.matrix(matrix(1:30, 10, 3))
y <- deepcopy(x, -1)    # Don't include the first column.
x
y
head(x)
head(y)