shard_lapply_shared: Apply a Function Over a List with Optional Auto-Sharing

In shard: Deterministic, Zero-Copy Parallel Execution for R

Apply a Function Over a List with Optional Auto-Sharing

Description

A convenience wrapper for list workloads that need supervision and shared inputs. Large atomic list elements are auto-shared based on policy.

Usage

shard_lapply_shared(
  x,
  FUN,
  VARS = NULL,
  workers = NULL,
  ...,
  policy = shard_apply_policy()
)

Arguments

x	A list.
FUN	Function of the form ⁠function(el, ...)⁠.
VARS	Optional named list of extra variables (auto-shared when large).
workers	Number of workers (passed to shard_map()).
...	Additional arguments forwarded to FUN.
policy	A shard_apply_policy() object.

Details

This wrapper enforces guardrails to avoid accidental huge gathers: it estimates the total gathered result size from a probe call and refuses to run if it exceeds policy$max_gather_bytes.

Value

A list of results, one per element of x.

Examples

res <- shard_lapply_shared(as.list(1:4), function(x) x^2)
pool_stop()
res

shard documentation built on April 3, 2026, 9:08 a.m.