matter_mat-class {matter} | R Documentation

## Out-of-Memory Matrices

### Description

The `matter_mat` class implements out-of-memory matrices.

### Usage

    ## Instance creation
    matter_mat(data, datamode = "double", paths = NULL,
                filemode = ifelse(all(file.exists(paths)), "r", "rw"),
                offset = c(0, cumsum(sizeof(datamode) * extent)[-length(extent)]),
                extent = if (rowMaj) rep(ncol, nrow) else rep(nrow, ncol),
                nrow = 0, ncol = 0, rowMaj = FALSE, dimnames = NULL,
                chunksize = getOption("matter.default.chunksize"), ...)

    ## Additional methods documented below

### Arguments

`data` | An optional data matrix which will be initially written to the data in virtual memory if provided.
`datamode` | A 'character' vector giving the storage mode of the data in virtual memory. Allowable values are the C types ('char', 'uchar', short', 'ushort', 'int', 'uint', 'long', 'ulong', 'float') and their R equivalents ('raw', 'logical', 'integer', 'numeric'). See `?datatypes` for details.
`paths` | A 'character' vector of the paths to the files where the data are stored. If 'NULL', then a temporary file is created using `tempfile`.
`filemode` | The read/write mode of the files where the data are stored. This should be 'r' for read-only access, or 'rw' for read/write access.
`offset` | A vector giving the offsets in number of bytes from the beginning of each file in 'paths', specifying the start of the data to be accessed for each file.
`extent` | A vector giving the length of the data for each file in 'paths', specifying the number of elements of size 'datamode' to be accessed from each file.
`nrow` | An optional number giving the total number of rows.
`ncol` | An optional number giving the total number of columns.
`rowMaj` | Whether the data should be stored in row-major order (as opposed to column-major order) in virtual memory. Defaults to 'FALSE', for efficient access to columns. Set to 'TRUE' for more efficient access to rows instead.
`dimnames` | The names of the matrix dimensions.
`chunksize` | The (suggested) maximum number of elements which should be accessed at once by summary functions and linear algebra. Ignored when explicitly subsetting the dataset.
`...` | Additional arguments to be passed to constructor.

### Value

An object of class `matter_mat`.

### Slots

`data`:

  This slot stores the information about locations of the data in virtual memory and within the files.

`datamode`:

  The storage mode of the accessed data when read into R. This is a 'character' vector of with possible values 'raw', 'logical', 'integer', 'numeric', or 'virtual'.

`paths`:

  A 'character' vector of the paths to the files where the data are stored.

`filemode`:

  The read/write mode of the files where the data are stored. This should be 'r' for read-only access, or 'rw' for read/write access.

`chunksize`:

  The maximum number of elements which should be loaded into memory at once. Used by methods implementing summary statistics and linear algebra. Ignored when explicitly subsetting the dataset.

`length`:

  The length of the data.

`dim`:

  Either 'NULL' for vectors, or an integer vector of length one of more giving the maximal indices in each dimension for matrices and arrays.

`names`:

  The names of the data elements for vectors.

`dimnames`:

  Either 'NULL' or the names for the dimensions. If not 'NULL', then this should be a list of character vectors of the length given by 'dim' for each dimension. This is always 'NULL' for vectors.

`ops`:

  Delayed operations to be applied on atoms.

### Extends

`matter`

### Creating Objects

`matter_mat` instances can be created through `matter_mat()` or `matter()`.

### Methods

Standard generic methods:

`x[i, j, ..., drop], x[i, j] <- value`:

  Get or set the elements of the matrix. Use `drop = NULL` to return a subset of the same class as the object.

`x %*% y`:

  Matrix multiplication. At least one matrix must be an in-memory R matrix (or vector).

`crossprod(x, y)`:

  Alias for t(x) %*% y.

`tcrossprod(x, y)`:

  Alias for x %*% t(y).

`cbind(x, ...), rbind(x, ...)`:

  Combine matrices by row or column.

`t(x)`:

  Transpose a matrix. This is a quick operation which only changes metadata and does not touch the out-of-memory data.

### Author(s)

Kylie A. Bemis

### See Also

`matter`

### Examples

    x <- matter_mat(1:100, nrow=10, ncol=10)
    x

[Package matter version 1.20.0 Index]