LowRankMatrix {BiocSingular} | R Documentation

## The LowRankMatrix class

### Description

Definitions of the LowRankMatrixSeed and LowRankMatrix classes and their associated methods. These classes are designed to provide a memory-efficient representation of a low-rank reconstruction, e.g., after a principal components analysis.

### Usage

    LowRankMatrixSeed(rotation, components)

    LowRankMatrix(rotation, components)

### Arguments

`rotation` | A matrix-like object where each row corresponds to a row of the LowRankMatrix object. This can alternatively be a LowRankMatrixSeed, in which case any value of `components` is ignored.
`components` | A matrix-like object where each row corresponds to a column of the LowRankMatrix object.

### Value

The `LowRankMatrixSeed` constructor will return a LowRankMatrixSeed object.

The `LowRankMatrix` constructor will return a LowRankMatrix object equivalent to `tcrossprod(rotation, components)`.

### Methods for LowRankMatrixSeed objects

LowRankMatrixSeed objects are implemented as DelayedMatrix backends. They support standard operations like `dim`, `dimnames` and `extract_array`.

Passing a LowRankMatrixSeed object to the `DelayedArray` constructor will create a LowRankMatrix object.

### Methods for LowRankMatrix objects

LowRankMatrix objects are derived from DelayedMatrix objects and support all of valid operations on the latter. Subsetting, transposition and replacement of row/column names are specialized for greater efficiency when operating on LowRankMatrix instances, and will return a new LowRankMatrix rather than a DelayedMatrix.

All other operations applied to a LowRankMatrix will use the underlying DelayedArray machinery. Unary or binary operations will generally create a new DelayedMatrix instance containing a LowRankMatrixSeed.

### Author(s)

Aaron Lun

### See Also

`runPCA` to generate the rotation and component matrices.

### Examples

    a <- matrix(rnorm(100000), ncol=20)
    out <- runPCA(a, rank=10)

    lr <- LowRankMatrix(out$rotation, out$x)

[Package BiocSingular version 1.0.0 Index]