reduce

AGGREGATIONS

1 Description

Generic function for reducing (accumulating) all datasets in the same HDF5 group as x into a single dataset using a binary operation.

2 Usage

reduce(x, ...)

3 Arguments

Parameter	Description
`x`	An .

4 Value

A new containing the accumulated result.

5 Examples

\donttest{
fn <- tempfile(fileext = ".h5")

# Create three matrices in the same group
hdf5_create_matrix(fn, "partials/chunk_0", data = matrix(1:100, 10, 10))
hdf5_create_matrix(fn, "partials/chunk_1", data = matrix(1:100, 10, 10))
hdf5_create_matrix(fn, "partials/chunk_2", data = matrix(1:100, 10, 10))

# Open one as entry point — reduce() operates on its whole group
partial <- hdf5_matrix(fn, "partials/chunk_0")
total   <- reduce(partial, func = "+")
dim(total)

hdf5_close_all()
unlink(fn)
}

6 See Also

hdf5_reduce for the standalone group-level version.

---
title: "reduce"
subtitle: "reduce"
---

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

## Description

Generic function for reducing (accumulating) all datasets in the same HDF5
group as `x` into a single dataset using a binary operation.

## Usage

```r
reduce(x, ...)
```
## Arguments

::: {.param-table}
| Parameter | Description |
|-----------|-------------|
| `x` | An \code{HDF5Matrix}. |
:::

## Value

::: {.return-value}
A new \code{HDF5Matrix} containing the accumulated result.

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

\donttest{
fn <- tempfile(fileext = ".h5")

# Create three matrices in the same group
hdf5_create_matrix(fn, "partials/chunk_0", data = matrix(1:100, 10, 10))
hdf5_create_matrix(fn, "partials/chunk_1", data = matrix(1:100, 10, 10))
hdf5_create_matrix(fn, "partials/chunk_2", data = matrix(1:100, 10, 10))

# Open one as entry point — reduce() operates on its whole group
partial <- hdf5_matrix(fn, "partials/chunk_0")
total   <- reduce(partial, func = "+")
dim(total)

hdf5_close_all()
unlink(fn)
}

```
## See Also

::: {.see-also}
[hdf5_reduce](hdf5_reduce.html) for the standalone group-level version.

:::