split.HDF5Matrix

split.HDF5Matrix

OTHER

1 Description

S3 method of base::split() for HDF5Matrix objects. Divides the matrix into blocks along rows (default) or columns.

Provide exactly ONE of n_blocks or block_size.

2 Usage

split.HDF5Matrix(...)

3 Arguments

Parameter	Description
`x`	An .
`f`	Ignored (kept for S3 signature compatibility).
`n_blocks`	Integer. Number of (roughly equal) blocks; -1 = unused.
`block_size`	Integer. Max rows (or cols) per block; -1 = unused.
`bycols`	Logical. If , split by columns (default = by rows).
`out_group`	Character. HDF5 group for output blocks (default ).
`out_dataset`	Character or NULL. Base dataset name.
`overwrite`	Logical. Overwrite existing blocks (default ).
`drop`	Ignored (S3 compatibility).

4 Value

Named list of objects: , , …

5 Examples

\donttest{

fn <- tempfile(fileext = ".h5")
X  <- hdf5_create_matrix(fn, "data/X", data = matrix(rnorm(2000000), 20000, 100))

X      <- hdf5_matrix( fn, "data/X")   # 20000 × 1000
blocks <- split(X, n_blocks = 4)             # 4 row-blocks of ~5000 rows each
}

---
title: "split.HDF5Matrix"
subtitle: "split.HDF5Matrix"
---

<span class="category-badge other">OTHER</span>

## Description

S3 method of `base::split()` for `HDF5Matrix` objects.
Divides the matrix into blocks along rows (default) or columns.

Provide exactly ONE of `n_blocks` or `block_size`.

## Usage

```r
split.HDF5Matrix(...)
```
## Arguments

::: {.param-table}
| Parameter | Description |
|-----------|-------------|
| `x` | An \code{HDF5Matrix}. |
| `f` | Ignored (kept for S3 signature compatibility). |
| `n_blocks` | Integer. Number of (roughly equal) blocks; -1 = unused. |
| `block_size` | Integer. Max rows (or cols) per block; -1 = unused. |
| `bycols` | Logical. If \code{TRUE}, split by columns (default = by rows). |
| `out_group` | Character. HDF5 group for output blocks (default \code{"SPLIT"}). |
| `out_dataset` | Character or NULL. Base dataset name. |
| `overwrite` | Logical. Overwrite existing blocks (default \code{FALSE}). |
| `drop` | Ignored (S3 compatibility). |
:::

## Value

::: {.return-value}
Named list of \code{HDF5Matrix} objects:
  \code{block_0}, \code{block_1}, …

:::
## Examples
```{r}
#| eval: false
#| warning: false

\donttest{

fn <- tempfile(fileext = ".h5")
X  <- hdf5_create_matrix(fn, "data/X", data = matrix(rnorm(2000000), 20000, 100))

X      <- hdf5_matrix( fn, "data/X")   # 20000 × 1000
blocks <- split(X, n_blocks = 4)             # 4 row-blocks of ~5000 rows each
}

```