Index of this worker
id = labindex
id = labindex returns the
index of the worker currently executing the function. labindex is
assigned to each worker when a job begins execution, and applies only
for the duration of that job. The value of labindex spans
from 1 to n, where n is
the number of workers running the current job, defined by numlabs.
View labindex in spmd blocks
and parfor-loops.
p = parpool('local',2); spmd labindex end
Lab 1:
1
Lab 2:
2Using the same two-worker pool, p:
parfor a=1:4 [a,labindex] end
ans =
3 1
ans =
2 1
ans =
1 1
ans =1
4 1
In an spmd block, because you have access
to all workers individually and control what gets executed on them,
each worker has a unique labindex.
However, inside a parfor-loop, labindex always
returns a value of 1 on all workers in all iterations.