Parallel Computing Toolbox™ 3.3

Parallel Programming in MATLAB®

Interactive Environment

matlabpool Command

The matlabpool command sets up an interactive environment for executing parallel for-loops using parfor. Within this environment, parfor can set up data and MATLAB® code exchange between a MATLAB client session and MATLAB workers. These operations happen automatically and, therefore, you as a user do not have to construct and submit jobs to the cluster.

The code that is executed in the environment set up using the matlabpool command can be set up for off-line execution using the batch command (for MATLAB scripts) or createMatlabpoolJob function (for MATLAB functions).

For more details, see Setting up MATLAB Resources and matlabpool sections in the documentation.

Parallel Command Window

The Parallel Command Window provides an interactive interface for executing MATLAB code directly on workers participating in the interactive parallel session. Commands issued at the pmode prompt are executed immediately on all the labs and results are returned immediately to the client session.

You can use distributed arrays, associated parallel functions, as well as message-passing functions in this mode. In fact, the commands you issue at the pmode prompt can be wrapped up into an MATLAB function and submitted as a job for offline execution.

This mode is very useful tool that facilitates the debugging process as it allows you to watch the results and the interaction between labs at each step. Through mpiprofile you can easily profile your parallel code from the Parallel Command Window.

For more details see Interactive Parallel Mode and Using the Parallel Profiler sections in the documentation.

An interactive parallel mode (pmode) session demonstrating pi estimation using parallel numerical quadrature on four workers. The output from each worker is shown. Click on image to see enlarged view.