delarr_seed_nd: Construct an N-dimensional seed backend for 'delarr'

In delarr: Lazy Delayed Arrays with Fused Execution

Construct an N-dimensional seed backend for delarr

Description

Creates a seed for arrays with 2 or more dimensions. The pull function receives a list of per-dimension index vectors and returns the corresponding sub-array.

Usage

delarr_seed_nd(
  dims,
  pull,
  chunk_hint = NULL,
  dimnames = NULL,
  begin = NULL,
  end = NULL
)

Arguments

dims	Integer vector of dimension extents (length >= 2).
pull	A function accepting a single argument indices — a named or positional list of integer vectors (one per dimension, or NULL for "all") — and returning an array with the requested sub-dimensions.
chunk_hint	Optional list describing preferred chunk sizes.
dimnames	Optional list of dimnames (one element per dimension).
begin	Optional function invoked before streaming begins.
end	Optional function invoked after streaming completes.

Value

An object of class delarr_seed.

Examples

arr <- array(seq_len(24), dim = c(3, 4, 2))
seed <- delarr_seed_nd(
  dims = c(3, 4, 2),
  pull = function(indices) {
    idx <- lapply(seq_along(dim(arr)), function(k) indices[[k]] %||% seq_len(dim(arr)[k]))
    do.call("[", c(list(arr), idx, list(drop = FALSE)))
  }
)
dim(seed)

delarr documentation built on July 1, 2026, 1:06 a.m.