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saveAsTallDatastore

Class: matlab.compiler.mlspark.RDD
Package: matlab.compiler.mlspark

Save RDD as a MATLAB tall array to a binary file that can be read back using the datastore function

Syntax

saveAsMatlabBinaryFile(obj,path)

Description

saveAsMatlabBinaryFile(obj,path) saves obj as a MATLAB® tall array in a binary file that can be read back using the datastore function. path specifies the directory location in which to save the binary file.

Input Arguments

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An input RDD, specified as a RDD object.

Directory location in which to save the binary file, specified as a character vector enclosed in ''.

Data Types: char

Examples

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Save an RDD as a MATLAB tall array to a binary file that can be read back using the datastore function.

%% Connect to Spark
sparkProp = containers.Map({'spark.executor.cores'}, {'1'});
conf = matlab.compiler.mlspark.SparkConf('AppName','myApp', ...
                        'Master','local[1]','SparkProperties',sparkProp);
sc = matlab.compiler.mlspark.SparkContext(conf);

%% saveAsTallDatastore 

% May require setting HADOOP_PREFIX or HADOOP_HOME environment variables to a
% valid Hadoop installation folder even if running locally.
% For example:
% setenv('HADOOP_PREFIX','/share/hadoop/hadoop-2.5.2')

inRDD = sc.parallelize({1,2,3,4,5});
% Store RDD in a file as a tall array that can be read back into MATLAB using datastore
inRDD.saveAsTallDatastore('myDir'); 
ds = datastore(['myDir' '/part*'], 'Type', 'tall');
ds.readall()
Introduced in R2016b