Simultaneously send data to and receive data from another worker
dataReceived = labSendReceive(rcvWkrIdx,srcWkrIdx,dataSent)
dataReceived = labSendReceive(rcvWkrIdx,srcWkrIdx,dataSent,tag)
| Data on the sending worker that is sent to the receiving worker; any MATLAB® data type. |
| Data accepted on the receiving worker. |
|
|
|
|
| Nonnegative integer to identify data. |
dataReceived = labSendReceive(rcvWkrIdx,srcWkrIdx,dataSent)
sends dataSent to the worker whose labindex is
rcvWkrIdx, and receives dataReceived from
the worker whose labindex is srcWkrIdx. The
values for arguments rcvWkrIdx and srcWkrIdx
must be scalars. This function is conceptually equivalent to the following sequence
of calls:
labSend(dataSent,rcvWkrIdx); dataReceived = labReceive(srcWkrIdx);
with the important exception that both the sending and receiving of data happens
concurrently. This can eliminate deadlocks that might otherwise occur if the
equivalent call to labSend would block.
If rcvWkrIdx is an empty array,
labSendReceive does not send data, but only receives. If
srcWkrIdx is an empty array,
labSendReceive does not receive data, but only sends.
dataReceived = labSendReceive(rcvWkrIdx,srcWkrIdx,dataSent,tag)
uses the specified tag for the communication. tag can be any
integer from 0 to 32767.
Create a unique set of data on each worker, and transfer each worker’s data one
worker to the right (to the next higher labindex).
First use the magic function to create a unique
value for the variant array mydata on each worker.
mydata = magic(labindex)
Lab 1:
mydata =
1
Lab 2:
mydata =
1 3
4 2
Lab 3:
mydata =
8 1 6
3 5 7
4 9 2Define the worker on either side, so that each worker will receive data from the worker on its “left,” while sending data to the worker on its “right,” cycling data from the end worker back to the beginning worker.
rcvWkrIdx = mod(labindex, numlabs) + 1; % one worker to the right srcWkrIdx = mod(labindex - 2, numlabs) + 1; % one worker to the left
Transfer the data, sending each worker’s mydata into the next
worker’s otherdata variable, wrapping the third worker’s data
back to the first worker.
otherdata = labSendReceive(rcvWkrIdx,srcWkrIdx,mydata)
Lab 1:
otherdata =
8 1 6
3 5 7
4 9 2
Lab 2:
otherdata =
1
Lab 3:
otherdata =
1 3
4 2Transfer data to the next worker without wrapping data from the last worker to the first worker.
if labindex < numlabs; rcvWkrIdx = labindex + 1; else rcvWkrIdx = []; end; if labindex > 1; srcWkrIdx = labindex - 1; else srcWkrIdx = []; end; otherdata = labSendReceive(rcvWkrIdx,srcWkrIdx,mydata)
Lab 1:
otherdata =
[]
Lab 2:
otherdata =
1
Lab 3:
otherdata =
1 3
4 2labBarrier | labindex | labProbe | labReceive | labSend | numlabs