User`s guide

6 Programming Overview
6-58
Create two MapReducer objects for specifying the different execution environments for
mapreduce.
inMatlab = mapreducer(0);
inPool = mapreducer(p);
Create and preview the datastore. The data set used in this example is available in
matlabroot/toolbox/matlab/demos.
ds = datastore('airlinesmall.csv','TreatAsMissing','NA',...
'SelectedVariableNames','ArrDelay','ReadSize',1000);
preview(ds)
ArrDelay
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Next, run the mapreduce calculation in the MATLAB client session. The map and reduce
functions are available in matlabroot/toolbox/matlab/demos.
meanDelay = mapreduce(ds,@meanArrivalDelayMapper,@meanArrivalDelayReducer,inMatlab);
********************************
* MAPREDUCE PROGRESS *
********************************
Map 0% Reduce 0%
Map 10% Reduce 0%
Map 20% Reduce 0%
Map 30% Reduce 0%
Map 40% Reduce 0%
Map 50% Reduce 0%
Map 60% Reduce 0%
Map 70% Reduce 0%
Map 80% Reduce 0%
Map 90% Reduce 0%
Map 100% Reduce 100%