hdf5_reduce

hdf5_reduce

AGGREGATIONS

1 Description

Applies a binary reduction ("+" or "-") across all datasets stored in a given HDF5 group and writes the result as a new dataset. Delegates to bdReduce_hdf5_dataset().

2 Usage

hdf5_reduce(...)

3 Arguments

Parameter	Description
`filename`	Path to the HDF5 file.
`group`	Group path containing the datasets to reduce.
`func`	Character. Reduction operator: (default) or .
`outgroup`	Character or . Output group (default: same as ).
`outdataset`	Character or . Output dataset name (default: same as ).
`overwrite`	Logical. Overwrite existing output dataset.
`remove`	Logical. Remove input datasets after reduction.

4 Value

An pointing to the result dataset.

5 Examples

\donttest{
fn <- tempfile(fileext = ".h5")
hdf5_create_matrix(fn, "blocks/A", data = matrix(1:6, 2, 3))
hdf5_create_matrix(fn, "blocks/B", data = matrix(1:6, 2, 3))
hdf5_create_matrix(fn, "blocks/C", data = matrix(1:6, 2, 3))
result <- hdf5_reduce(fn, group = "blocks", func = "+")
as.matrix(result)
hdf5_close_all()
unlink(fn)
}

6 See Also

hdf5_apply, cbind.HDF5Matrix

---
title: "hdf5_reduce"
subtitle: "hdf5_reduce"
---

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

## Description

Applies a binary reduction (`"+"` or `"-"`) across all
datasets stored in a given HDF5 group and writes the result as a new
dataset. Delegates to `bdReduce_hdf5_dataset()`.

## Usage

```r
hdf5_reduce(...)
```
## Arguments

::: {.param-table}
| Parameter | Description |
|-----------|-------------|
| `filename` | Path to the HDF5 file. |
| `group` | Group path containing the datasets to reduce. |
| `func` | Character. Reduction operator: \code{"+"} (default)   or \code{"-"}. |
| `outgroup` | Character or \code{NULL}. Output group   (default: same as \code{group}). |
| `outdataset` | Character or \code{NULL}. Output dataset name   (default: same as \code{group}). |
| `overwrite` | Logical. Overwrite existing output dataset. |
| `remove` | Logical. Remove input datasets after reduction. |
:::

## Value

::: {.return-value}
An \code{HDF5Matrix} pointing to the result dataset.

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

\donttest{
fn <- tempfile(fileext = ".h5")
hdf5_create_matrix(fn, "blocks/A", data = matrix(1:6, 2, 3))
hdf5_create_matrix(fn, "blocks/B", data = matrix(1:6, 2, 3))
hdf5_create_matrix(fn, "blocks/C", data = matrix(1:6, 2, 3))
result <- hdf5_reduce(fn, group = "blocks", func = "+")
as.matrix(result)
hdf5_close_all()
unlink(fn)
}

```
## See Also

::: {.see-also}
[hdf5_apply](hdf5_apply.html), [cbind.HDF5Matrix](cbind.HDF5Matrix.html)
:::