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Estimate Tile Processing Needs

Source: R/utils.R
geomorphon_chunks_needed.Rd

geomorphon_chunks_needed() is a heuristic for number of tiles needed to calculate geomorphons on larger-than-memory rasters. Allows for scaling by number of parallel workers, a multiplicative factor for the memory needs, and a multiplicative factor for worker needs.

Usage

geomorphon_chunks_needed(
  x,
  workers = Sys.getenv("R_RGEOMORPHON_N_WORKERS", unset = 1),
  scl_need = Sys.getenv("R_RGEOMORPHON_MEM_SCALE_NEED", unset = 10),
  scl_workers = Sys.getenv("R_RGEOMORPHON_MEM_SCALE_WORKERS", unset = 1),
  pow_total = Sys.getenv("R_RGEOMORPHON_MEM_POWER", unset = 0.5)
)

Arguments

x

A SpatRaster object.

workers

integer. Number of parallel workers. Default uses value of environment variable R_RGEOMORPHON_N_WORKERS. If unset, 1

scl_need

numeric. Scaling factor for memory needs. Default uses value of environment variable R_RGEOMORPHON_MEM_SCALE_NEED. If unset, 10.

scl_workers

numeric. Scaling factor for each worker. Default uses value of environment variable R_RGEOMORPHON_MEM_SCALE_WORKERS. If unset, 1.

pow_total

numeric. Exponent for scaling total number of chunks. Default uses value of environment variable R_RGEOMORPHON_MEM_POWER. If unset, 1.

Value

integer. Number of tile chunks to divide x into.

Examples


data("salton", package = "rgeomorphon")

x <- terra::rast(salton)
terra::ext(x) <- attr(salton, "extent")
terra::crs(x) <- attr(salton, "crs")

geomorphon_chunks_needed(x)
#> [1] 1