Total number of workers operating in parallel on current
n = numlabs
n = numlabs returns the total
number of workers currently operating on the current job. This value
is the maximum value that can be used with labSend and labReceive.
In an spmd block, numlabs on
each worker returns the parallel pool size.
However, inside a parfor-loop, numlabs always
returns a value of 1.
labindex | labSendReceive