split_dataset

split_dataset

AGGREGATIONS

1 Description

Splits an HDF5Matrixinto equal-sized sub-matrices stored as separate datasets in the same HDF5 file.

Output datasets are named <out_group>/<out_dataset>.0, <out_group>/<out_dataset>.1, (0-based index).

Exactly one of n_blocks or block_size must be provided.

2 Usage

split_dataset(...)

3 Arguments

Parameter	Description
`x`	An .
`n_blocks`	Integer or . Number of blocks.
`block_size`	Integer or . Rows or columns per block.
`bycols`	Logical. Split by columns () or rows (default ).
`out_group`	Character. Output HDF5 group (default ).
`out_dataset`	Character or NULL. Base dataset name.
`overwrite`	Logical. Overwrite existing blocks (default ).

4 Value

A named list of objects.

5 Examples

\donttest{
tmp  <- tempfile(fileext = ".h5")
M    <- hdf5_create_matrix(tmp, "data/M", data = matrix(1:60, 6, 10))
blks <- split_dataset(M, n_blocks = 3L)
length(blks)
lapply(blks, close)
close(M)
unlink(tmp)
}

6 See Also

\link[BigDataStatMeth]{cbind.HDF5Matrix}

---
title: "split_dataset"
subtitle: "split_dataset"
---

<span class="category-badge aggregations">AGGREGATIONS</span>

## Description

Splits an `HDF5Matrix`into equal-sized sub-matrices
stored as separate datasets in the same HDF5 file.

Output datasets are named `<out_group>/<out_dataset>.0`,
`<out_group>/<out_dataset>.1`, \ldots (0-based index).

Exactly one of `n_blocks` or `block_size` must be provided.

## Usage

```r
split_dataset(...)
```
## Arguments

::: {.param-table}
| Parameter | Description |
|-----------|-------------|
| `x` | An \code{HDF5Matrix}. |
| `n_blocks` | Integer or \code{NULL}. Number of blocks. |
| `block_size` | Integer or \code{NULL}. Rows or columns per block. |
| `bycols` | Logical. Split by columns (\code{TRUE}) or rows (default \code{FALSE}). |
| `out_group` | Character. Output HDF5 group (default \code{"SPLIT"}). |
| `out_dataset` | Character or NULL. Base dataset name. |
| `overwrite` | Logical. Overwrite existing blocks (default \code{FALSE}). |
:::

## Value

::: {.return-value}
A named list of \code{HDF5Matrix} objects.

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

\donttest{
tmp  <- tempfile(fileext = ".h5")
M    <- hdf5_create_matrix(tmp, "data/M", data = matrix(1:60, 6, 10))
blks <- split_dataset(M, n_blocks = 3L)
length(blks)
lapply(blks, close)
close(M)
unlink(tmp)
}

```
## See Also

::: {.see-also}
`\link[BigDataStatMeth]{cbind.HDF5Matrix`}
:::