parfor - Parallel for-loop - MATLAB (original) (raw)
Main Content
Syntax
Description
parfor _`loopvar`_ = _`initval`_:_`endval`_; _`statements`_; end executes a series of MATLAB® statements for values of loopvar betweeninitval and endval, inclusive, which specify a vector of increasing integer values. The loop runs in parallel when you have Parallel Computing Toolbox™ or when you create a MEX function or standalone code with MATLAB Coder™. Unlike a traditional for-loop, iterations are not executed in a guaranteed order. You cannot call scripts directly in aparfor-loop. However, you can call functions that call scripts.
parfor (_`loopvar`_ = _`initval`_:_`endval`_, M); _`statements`_; end executes statements in a loop using a maximum of M workers or threads, where M is a nonnegative integer.
Examples
Perform three large eigenvalue computations using three workers or cores with Parallel Computing Toolbox:
parpool(3) parfor i=1:3, c(:,i) = eig(rand(1000)); end
Tips
- If you have Parallel Computing Toolbox, see for parfor (Parallel Computing Toolbox) and parpool (Parallel Computing Toolbox) for additional information.
- If you have MATLAB Coder, see parfor (MATLAB Coder) for additional information.
Extended Capabilities
If you have Parallel Computing Toolbox installed, then when you use parfor, MATLAB automatically opens a parallel pool of workers on your local machine. MATLAB runs the loop across the available workers. Control parallel behavior with the parallel preferences, including scaling up to a cluster.
For details, see Parallel for-Loops (parfor) (Parallel Computing Toolbox).
Version History
Introduced in R2008a