colOrderStats {DelayedMatrixStats} | R Documentation

## Gets an order statistic for each row (column) in a matrix

### Description

Gets an order statistic for each row (column) in a matrix.

### Usage

    colOrderStats(x, rows = NULL, cols = NULL, which, dim. = dim(x), ...)

    rowOrderStats(x, rows = NULL, cols = NULL, which, dim. = dim(x), ...)

    ## S4 method for signature 'DelayedMatrix'
    colOrderStats(x, rows = NULL, cols = NULL, which,
      dim. = dim(x), force_block_processing = FALSE, ...)

    ## S4 method for signature 'DelayedMatrix'
    rowOrderStats(x, rows = NULL, cols = NULL, which,
      dim. = dim(x), force_block_processing = FALSE, ...)

### Arguments

`x` | A NxK DelayedMatrix.
`rows` | A `vector` indicating subset of rows (and/or columns) to operate over. If `NULL`, no subsetting is done.
`cols` | A `vector` indicating subset of rows (and/or columns) to operate over. If `NULL`, no subsetting is done.
`which` | An `integer` index in [1,K] ([1,N]) indicating which order statistic to be returned.
`dim.` | An `integer` `vector` of length two specifying the dimension of `x`, also when not a `matrix`.
`...` | Additional arguments passed to specific methods.
`force_block_processing` | `FALSE` (the default) means that a seed-aware, optimised method is used (if available). This can be overridden to use the general block-processing strategy by setting this to `TRUE` (typically not advised). The block-processing strategy loads one or more (depending on `getOption("DelayedArray.block.size")`) columns (`colFoo()`) or rows (`rowFoo()`) into memory as an ordinary base::array.

### Details

The implementation of `rowOrderStats()` is optimized for both speed and memory. To avoid coercing to `double`s (and hence memory allocation), there is a unique implementation for `integer` matrices.

### Value

Returns a `numeric` `vector` of length N (K).

### Missing values

This method does not handle missing values, that is, the result corresponds to having `na.rm = FALSE` (if such an argument would be available).

### See Also

See `rowMeans()` in `colSums`().

### Examples

    # A DelayedMatrix with a 'Matrix' seed
    dm_Matrix <- DelayedArray(Matrix::Matrix(c(rep(1L, 5),
                                               as.integer((0:4) ^ 2),
                                               seq(-5L, -1L, 1L)),
                                             ncol = 3))
    # Only using columns 2-3
    colOrderStats(dm_Matrix, cols = 2:3, which = 1)

    # Different algorithms, specified by `which`, may give different results
    rowOrderStats(dm_Matrix, which = 1)
    rowOrderStats(dm_Matrix, which = 2)

[Package DelayedMatrixStats version 1.0.3 Index]