Materialise a delayed matrix

Streams column chunks from the backing seed, applying deferred operations and optional reductions on the fly. By default the result is returned as a base matrix or vector; alternatively, supply a writer via into to stream the output elsewhere (e.g., hdf5_writer()).

Usage

collect(
  x,
  into = NULL,
  chunk_size = NULL,
  chunk_margin = c("cols", "rows"),
  target_bytes = NULL,
  parallel = FALSE,
  workers = NULL,
  optimize = TRUE
)

Arguments

x

A delarr object.

into

Optional writer or callback used to receive streamed chunks.

chunk_size

Optional chunk size along chunk_margin.

chunk_margin

Chunking axis for non-reduction collection.

target_bytes

Optional memory budget (bytes) used to adapt chunk size.

parallel

Logical; attempt parallel chunk execution when safe.

workers

Number of worker processes when parallel = TRUE.

optimize

Logical; run lightweight DAG optimizations before evaluation.

Value

A realised matrix/vector, or NULL invisibly when writing to into.

Examples

# Basic materialization
mat <- matrix(1:12, nrow = 3, ncol = 4)
darr <- delarr(mat)
collect(darr)
#>      [,1] [,2] [,3] [,4]
#> [1,]    1    4    7   10
#> [2,]    2    5    8   11
#> [3,]    3    6    9   12

# Collect after lazy operations
result <- darr |>
  d_map(~ .x^2) |>
  collect()
result
#>      [,1] [,2] [,3] [,4]
#> [1,]    1   16   49  100
#> [2,]    4   25   64  121
#> [3,]    9   36   81  144