buffer: Shared Memory Buffers

Description

Create typed writable output buffers backed by shared memory for cross-process writes during parallel execution.

Creates a typed output buffer backed by shared memory that can be written to by parallel workers using slice assignment.

Usage

buffer(
  type = c("double", "integer", "logical", "raw"),
  dim,
  init = NULL,
  backing = c("auto", "mmap", "shm")
)

Value

An S3 object of class "shard_buffer" that supports:

Slice assignment: buf[idx] <- values
Slice reading: buf[idx]
Full extraction: buf[]
Conversion to R vector: as.vector(buf), as.double(buf), etc.

Arguments

type: Character. Data type: "double" (default), "integer", "logical", or "raw".
dim: Integer vector. Dimensions of the buffer. For a vector, specify the length. For a matrix, specify c(nrow, ncol). For arrays, specify all dimensions.
init: Initial value to fill the buffer. Default is type-appropriate zero (0, 0L, FALSE, or raw(0)).
backing: Backing type for shared memory: "auto" (default), "mmap", or "shm".

Details

Buffers provide an explicit output mechanism for shard_map. Instead of returning results from workers (which requires serialization and memory copying), workers write directly to shared buffers.

Supported types:

"double": 8-byte floating point (default)
"integer": 4-byte signed integer
"logical": 4-byte logical (stored as integer)
"raw": 1-byte raw data

Buffers support slice assignment using standard R indexing: buf[1:100] <- values

Examples

Run this code

# \donttest{
out <- buffer("double", dim = 100)
out[1:10] <- rnorm(10)
result <- out[]
# }