big.matrix-class: Class "big.matrix"
In bigmemory: Manage Massive Matrices with Shared Memory and Memory-Mapped Files

big.matrix-class

R Documentation

Class "big.matrix"

Description

The big.matrix class is designed for matrices with elements of type double, integer, short, or char. A big.matrix acts much like a traditional R matrix, but helps protect the user from many inadvertent memory-consuming pitfalls of traditional R matrices and data frames. The objects are allocated to shared memory, and if file-backing is used they may exceed virtual memory in size. Sadly, 32-bit operating system constraints – largely Windows and some MacOS versions –will be a limiting factor with file-backed matrices; 64-bit operating systems are recommended.

Objects from the Class

Unlike many R objects, objects should not be created by calls of the form new("big.matrix", ...). The functions big.matrix() and filebacked.big.matrix() are intended for the user.

Slots

address:: Object of class "externalptr" points to the memory location of the C++ data structure.

Methods

As you would expect:

[<-: signature(x = "big.matrix", i = "ANY", j = "ANY"): ...
[<-: signature(x = "big.matrix", i = "ANY", j = "missing"): ...
[<-: signature(x = "big.matrix", i = "missing", j = "ANY"): ...
[<-: signature(x = "big.matrix", i = "missing", j = "missing"): ...
[<-: signature(x = "big.matrix", i = "matrix", j = "missing"): ...
[: signature(x = "big.matrix", i = "ANY", j = "ANY", drop = "missing"): ...
[: signature(x = "big.matrix", i = "ANY", j = "ANY", drop = "logical"): ...
[: signature(x = "big.matrix", i = "ANY", j = "missing", drop = "missing"): ...
[: signature(x = "big.matrix", i = "ANY", j = "missing", drop = "logical"): ...
[: signature(x = "big.matrix", i = "matrix", j = "missing", drop = "logical"): ...
[: signature(x = "big.matrix", i = "missing", j = "ANY", drop = "missing"): ...
[: signature(x = "big.matrix", i = "missing", j = "ANY", drop = "logical"): ...
[: signature(x = "big.matrix", i = "missing", j = "missing", drop = "missing"): ...
[: signature(x = "big.matrix", i = "missing", j = "missing", drop = "logical"): ...

The following are probably more interesting:

describe: signature(x = "big.matrix"): provide necessary and sufficient information for the sharing or re-attaching of the object.
dim: signature(x = "big.matrix"): returns the dimension of the big.matrix.
length: signature(x = "big.matrix"): returns the product of the dimensions of the big.matrix.
dimnames<-: signature(x = "big.matrix", value = "list"): set the row and column names, prohibited by default (see bigmemory to override).
dimnames: signature(x = "big.matrix"): get the row and column names.
head: signature(x = "big.matrix"): get the first 6 (or n) rows.
as.matrix: signature(x = "big.matrix"): coerce a big.matrix to a matrix.
is.big.matrix: signature(x = "big.matrix"): return TRUE if it's a big.matrix.
is.filebacked: signature(x = "big.matrix"): return TRUE if there is a file-backing.
is.separated: signature(x = "big.matrix") : return TRUE if the big.matrix is organized as a separated column vectors.
is.sub.big.matrix: signature(x = "big.matrix"): return TRUE if this is a sub-matrix of a big.matrix.
ncol: signature(x = "big.matrix"): returns the number of columns.
nrow: signature(x = "big.matrix"): returns the number of rows.
print: signature(x = "big.matrix"): a traditional print() is intentionally disabled, and returns head(x) unless options()$bm.print.warning==FALSE; in this case, print(x[,]) is the result, which could be very big!
sub.big.matrix: signature(x = "big.matrix"): for contiguous submatrices.
tail: signature(x = "big.matrix"): returns the last 6 (or n) rows.
typeof: signature(x = "big.matrix"): return the type of the atomic elements of the big.matrix.
write.big.matrix: signature(bigMat = "big.matrix", fileName = "character"): produce an ASCII file from the big.matrix.
apply: signature(x = "big.matrix"): apply() where MARGIN may only be 1 or 2, but otherwise conforming to what you would expect from apply().