Validate Grid State for Isolated Pixels — validate_no_isolated

Checks that no black pixel is completely isolated (has no black neighbors). An isolated pixel indicates a bug in the simulation logic. Also validates that the grid has at least one black pixel, as the number of black pixels should increase monotonically from the initial center pixel.

Usage

validate_no_isolated_pixels(
  grid,
  neighborhood = "4-hood",
  boundary = "terminate",
  strict = FALSE,
  last_black_positions = NULL,
  walkers = NULL,
  step_count = NULL
)

Arguments

grid: Numeric matrix representing the grid.
neighborhood: Character, "4-hood" or "8-hood" for neighbor checking. Default is "4-hood".
boundary: Character. "terminate" or "wrap". Default "terminate".
strict: Logical, if TRUE throws error on isolation, if FALSE logs warning. Default FALSE.
last_black_positions: Matrix of previously validated black pixel positions (optional). Used for optimization - only checks NEW pixels since last validation. Default NULL (checks all pixels).
walkers: List of walker objects (optional). Used for detailed debugging output when isolation detected. Default NULL.
step_count: Integer simulation step count (optional). Used for detailed debugging output when isolation detected. Default NULL.

Value

Logical, TRUE if valid (no isolated pixels), FALSE otherwise.

Examples

grid <- initialize_grid(10)
#> INFO [2026-02-03 16:36:09] Initializing grid of size 10x10
validate_no_isolated_pixels(grid)  # TRUE for single center pixel initially
#> [1] TRUE

# Create invalid grid with isolated pixel
bad_grid <- initialize_grid(10, center_black = FALSE)
#> INFO [2026-02-03 16:36:09] Initializing grid of size 10x10
bad_grid[3, 3] <- 1
validate_no_isolated_pixels(bad_grid)  # FALSE - isolated pixel
#> [1] TRUE