Get current mapreducer configuration
mr = gcmr returns an object representing
the current global execution environment for
If no global execution environment exists, then
mapreducerto set the global execution environment to be the default.
If a global execution environment currently exists, then
gcmrreturns the last visible MapReducer object created.
When you create a MapReducer object using
mapreducer, the object sets the global execution environment. The global execution environment persists even if the object representing it is later deleted.
If the global execution environment is deleted or invalid, then
gcmrreturns the next visible MapReducer object available. For example,
delete(gcmr)deletes the current global execution environment.
gcmr function defines the global execution
mapreduce, and is most likely
used with Parallel Computing Toolbox™, MATLAB®
If you do not specify a configuration to use in your call to
then by default
mapreduce uses the configuration
returned (or generated) by
mr = gcmr('nocreate') returns the current
global execution environment for
one already exists. If no global execution environment exists, then
If you have Parallel Computing Toolbox, see the
mapreducer(Parallel Computing Toolbox) function reference page for related information.
If you have MATLAB Compiler, see the
mapreducer(MATLAB Compiler) function reference page for related information.
Automatic Parallel Support
Accelerate code by automatically running computation in parallel using Parallel Computing Toolbox™.
If you have Parallel Computing Toolbox installed, when you use
gcmr, MATLAB automatically opens a parallel pool of workers on your local machine.
Control parallel behavior with the parallel preferences, including scaling up to a
For details, see Run mapreduce on a Parallel Pool (Parallel Computing Toolbox) or Use Tall Arrays on a Parallel Pool (Parallel Computing Toolbox). For more general information about parallel computing, see Run MATLAB Functions with Automatic Parallel Support (Parallel Computing Toolbox).
Introduced in R2014b