describe,big.matrix-method {bigmemory} | R Documentation |
The describe
function returns the information needed by
attach.big.matrix
to reference a shared or file-backed
big.matrix
object.
The attach.big.matrix
and attach.resource
functions create a
new big.matrix
object based on the descriptor information referencing
previously allocated shared-memory or file-backed matrices.
## S4 method for signature 'big.matrix' describe(x) attach.big.matrix(obj, ...)
x |
a |
obj |
an object as returned by |
... |
possibly |
The describe
function returns a list of the information needed to
attach to a big.matrix
object.
A descriptor file is automatically created when a new filebacked
big.matrix
is created.
describe
returns a list of of the information needed to attach to
a big.matrix
object.
attach.big.matrix
return a new instance of type big.matrix
corresponding to a shared-memory or file-backed big.matrix
.
Michael J. Kane and John W. Emerson <bigmemoryauthors@gmail.com>
bigmemory
, big.matrix
, or the class
documentation big.matrix
.
# The example is quite silly, as you wouldn't likely do this in a # single R session. But if zdescription were passed to another R session # via SNOW, foreach, or even by a simple file read/write, # then the attach of the second R process would give access to the # same object in memory. Please see the package vignette for real examples. z <- big.matrix(3, 3, type='integer', init=3) z[,] dim(z) z[1,1] <- 2 z[,] zdescription <- describe(z) zdescription y <- attach.big.matrix(zdescription) y[,] y z zz <- attach.resource(zdescription) zz[1,1] <- -100 y[,] z[,]