bigmemory: sub.big.matrix – R documentation

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sub.big.matrix

Submatrix support

Description

This doesn't create a copy, it just provides a new version of the class which provides behavior for a contiguous submatrix of the big.matrix. Non-contiguous submatrices are not supported.

Usage

is.sub.big.matrix(x)

## S4 method for signature 'big.matrix'
is.sub.big.matrix(x)

sub.big.matrix(
  x,
  firstRow = 1,
  lastRow = NULL,
  firstCol = 1,
  lastCol = NULL,
  backingpath = NULL
)

## S4 method for signature 'big.matrix'
sub.big.matrix(
  x,
  firstRow = 1,
  lastRow = NULL,
  firstCol = 1,
  lastCol = NULL,
  backingpath = NULL
)

Arguments

`x`	either a `big.matrix` or a descriptor.
`firstRow`	the first row of the submatrix.
`lastRow`	the last row of the submatrix if not `NULL`.
`firstCol`	the first column of the submatrix.
`lastCol`	the last column of the submatrix if not `NULL`.
`backingpath`	required path to the filebacked object, if applicable.

Details

The sub.big.matrix function allows a user to create a big.matrix object that references a contiguous set of columns and rows of another big.matrix object.

The is.sub.big.matrix function returns TRUE if the specified argument is a sub.big.matrix object and return FALSE otherwise.

Value

A big.matrix which is actually a submatrix of a larger big.matrix. It is not a physical copy. Only contiguous blocks may form a submatrix.

Author(s)

John W. Emerson and Michael J. Kane

Examples

x <- big.matrix(10, 5, init=0, type="double")
x[,] <- 1:50
y <- sub.big.matrix(x, 2, 9, 2, 3)
y[,]
y[1,1] <- -99
x[,]
rm(x)

bigmemory

Manage Massive Matrices with Shared Memory and Memory-Mapped Files

v4.5.36

LGPL-3 | Apache License 2.0

Authors

Michael J. Kane <kaneplusplus@gmail.com>, John W. Emerson <jayemerson@gmail.com>, Peter Haverty <haverty.peter@gene.com>, and Charles Determan Jr. <cdetermanjr@gmail.com>

Initial release