C++ API Reference for Intel® Data Analytics Acceleration Library 2019 Update 5

set_number_of_threads.cpp

/* file: set_number_of_threads.cpp */
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/*
! Content:
! C++ example of setting the maximum number of threads
!******************************************************************************/
#include "daal.h"
#include "service.h"
using namespace std;
using namespace daal;
using namespace daal::algorithms;
/* Input data set parameters */
string datasetFileName = "../data/batch/kmeans_dense.csv";
/* K-Means algorithm parameters */
const size_t nClusters = 20;
const size_t nIterations = 5;
const size_t nThreads = 2;
size_t nThreadsInit;
size_t nThreadsNew;
int main(int argc, char *argv[])
{
checkArguments(argc, argv, 1, &datasetFileName);
/* Get the number of threads that is used by the library by default */
nThreadsInit = services::Environment::getInstance()->getNumberOfThreads();
/* Set the maximum number of threads to be used by the library */
services::Environment::getInstance()->setNumberOfThreads(nThreads);
/* Get the number of threads that is used by the library after changing */
nThreadsNew = services::Environment::getInstance()->getNumberOfThreads();
/* Initialize FileDataSource to retrieve the input data from a .csv file */
FileDataSource<CSVFeatureManager> dataSource(datasetFileName, DataSource::doAllocateNumericTable,
DataSource::doDictionaryFromContext);
/* Retrieve the data from the input file */
dataSource.loadDataBlock();
/* Get initial clusters for the K-Means algorithm */
kmeans::init::Batch<float, kmeans::init::randomDense> init(nClusters);
init.input.set(kmeans::init::data, dataSource.getNumericTable());
init.compute();
NumericTablePtr centroids = init.getResult()->get(kmeans::init::centroids);
/* Create an algorithm object for the K-Means algorithm */
kmeans::Batch<> algorithm(nClusters, nIterations);
algorithm.input.set(kmeans::data, dataSource.getNumericTable());
algorithm.input.set(kmeans::inputCentroids, centroids);
/* Run computations */
algorithm.compute();
cout << "Initial number of threads: " << nThreadsInit << endl;
cout << "Number of threads to set: " << nThreads << endl;
cout << "Number of threads after setting: " << nThreadsNew << endl;
return 0;
}

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