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Execute Walker Step (Worker)

worker_step_walker.Rd

Executes one step of a walker using cached grid state. This is the main work function executed by crew workers.

Usage

worker_step_walker(
  walker,
  grid_state,
  worker_state,
  neighborhood = "4-hood",
  boundary = "terminate",
  max_steps = 10000L
)

Arguments

walker

List. Walker object (from create_walker()).

grid_state

List. Contains grid matrix and black_pixels set.

worker_state

List. Worker state from worker_init().

neighborhood

Character. "4-hood" or "8-hood" (default: "4-hood").

boundary

Character. "terminate" or "wrap" (default: "terminate").

max_steps

Integer. Maximum steps before forced termination (default: 10000).

Value

Modified walker object after one step.

Details

Performs one iteration of the random walk:

  1. Check for grid updates (refresh cache)

  2. Move walker one step using step_walker()

  3. Check termination using cached black pixels

The worker uses its local cache of black pixels to check termination conditions. This avoids querying the main process on every step, significantly reducing synchronization overhead.

Cache staleness is acceptable because:

  • Random walks are stochastic (small delays don't affect statistical properties)

  • Updates are broadcast immediately when walkers terminate

  • Worker checks for updates before each step

See also

step_walker, check_termination

Examples

if (FALSE) { # \dontrun{
# Step a walker in a worker process
walker <- worker_step_walker(
  walker = walker,
  grid_state = grid_state,
  worker_state = worker_state,
  neighborhood = "4-hood",
  boundary = "terminate"
)
} # }