pmode

(To be removed) Interactive Parallel Command Window

pmode will be removed in a future release. Use spmd instead. For more information, see pmode will be removed.

Syntax

pmode start
pmode start numworkers
pmode start prof numworkers
pmode quit
pmode exit
pmode client2lab clientvar workers workervar
pmode lab2client workervar worker clientvar
pmode cleanup prof


Description

pmode allows the interactive parallel execution of MATLAB^® commands. pmode achieves this by defining and submitting a communicating job, and opening a Parallel Command Window connected to the workers running the job. The workers then receive commands entered in the Parallel Command Window, process them, and send the command output back to the Parallel Command Window. Variables can be transferred between the MATLAB client and the workers.

pmode start starts pmode, using the default profile to define the cluster and number of workers. (The initial default profile is local; you can change it by using the function parallel.defaultClusterProfile.) You can also specify the number of workers using pmode start numworkers.

pmode start prof numworkers starts pmode using the Parallel Computing Toolbox™ profile prof to locate the cluster, submits a communicating job with the number of workers identified by numworkers, and connects the Parallel Command Window with the workers. If the number of workers is specified, it overrides the minimum and maximum number of workers specified in the profile.

pmode quit or pmode exit stops the pmode job, deletes it, and closes the Parallel Command Window. You can enter this command at the MATLAB prompt or the pmode prompt.

pmode client2lab clientvar workers workervar copies the variable clientvar from the MATLAB client to the variable workervar on the workers identified by workers. If workervar is omitted, the copy is named clientvar. workers can be either a single index or a vector of indices. You can enter this command at the MATLAB prompt or the pmode prompt.

pmode lab2client workervar worker clientvar copies the variable workervar from the worker identified by worker, to the variable clientvar on the MATLAB client. If clientvar is omitted, the copy is named workervar. You can enter this command at the MATLAB prompt or the pmode prompt. Note: If you use this command in an attempt to transfer a codistributed array to the client, you get a warning, and only the local portion of the array on the specified worker is transferred. To transfer an entire codistributed array, first use the gather function to assemble the whole array into the worker workspaces.

pmode cleanup prof deletes all communicating jobs created by pmode for the current user running on the cluster specified in the profile prof, including jobs that are currently running. The profile is optional; the default profile is used if none is specified. You can enter this command at the MATLAB prompt or the pmode prompt.

You can invoke pmode as either a command or a function, so the following are equivalent.

pmode start prof 4
pmode('start','prof',4)

Examples

In the following examples, the pmode prompt (P>>) indicates commands entered in the Parallel Command Window. Other commands are entered in the MATLAB Command Window.

Start pmode using the default profile to identify the cluster and number of workers.

pmode start

Start pmode using the local profile with four local workers.

pmode start local 4

Start pmode using the profile myProfile and eight workers on the cluster.

pmode start myProfile 8

Execute a command on all workers.

P>> x = 2*labindex;

Copy the variable x from worker 7 to the MATLAB client.

pmode lab2client x 7

Copy the variable y from the MATLAB client to workers 1 through 8.

pmode client2lab y 1:8

Display the current working directory of each worker.

P>> pwd

Compatibility Considerations

pmode will be removed

Warns starting in R2020a

In a future release, the pmode function will be removed. To execute commands interactively on multiple workers, use spmd instead.