hdf5_reduce: Reduce all datasets in an HDF5 group by a binary operation

In BigDataStatMeth: Title: Scalable Statistical Computing with HDF5-Backed Matrices

Reduce all datasets in an HDF5 group by a binary operation

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

hdf5_reduce(
  filename,
  group,
  func = "+",
  outgroup = NULL,
  outdataset = NULL,
  overwrite = FALSE,
  remove = FALSE
)

Arguments

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

Value

An HDF5Matrix pointing to the result dataset.

See Also

hdf5_apply, cbind.HDF5Matrix

Examples

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)

BigDataStatMeth documentation built on May 15, 2026, 1:07 a.m.