Worker Array

The worker array W contains information about each worker’s state. Used within allocation functions to determine which workers are eligible to receive work.

W: numpy structured array
    "worker_id" [int]:
        The worker ID
    "active" [int]:
        Is the worker active or not
    "persis_state" [int]:
        Is the worker in a persis_state
    "active_recv" [int]:
        Is the worker in an active receive state
    "blocked" [int]:
        Is the worker's resources blocked by another calculation

We use the following convention:

Worker state	active	persis_state	blocked
idle worker	0	0	0
active, nonpersistent sim	1	0	0
active, nonpersistent gen	2	0	0
active, persistent sim	1	1	0
active, persistent gen	2	2	0
waiting, persistent sim	0	1	0
waiting, persistent gen	0	2	0
worker blocked by some other calculation	1	0	1

Note

libEnsemble’s manager receives only from workers with a nonzero "active" state
libEnsemble’s manager calls the alloc_f only if some worker has an "active" state of zero, or is in an active receive state.