Pool.map_prepare()

Stage a map once for repeated runs; return a

Usage

Source

Pool.map_prepare(
    fn,
    x,
    *,
    args=(),
    kwargs=None,
    n_chunks=None,
    seed=None,
    template=None,
    collect=None,
    stream=False,
)

PreparedMap.

Takes the same arguments as map() (minus timeout, which is per-run and moves to PreparedMap.run). The descriptor pickle, the region create, and the worker-side attach are paid once here; each pm.run() re-arms in O(1), reuses the workers’ cached contexts, and returns the run’s map handle (the collect happens on it). A run collected with collect="view" hands its region to the view, so the next run restages into a fresh one. With stream=True the staged x stays submitter-side, so a replacement x of any shape simply re-slices — only a length change under template restages (the output area is sized for the staged length). Close the handle (or use it as a context manager) to unlink the region.