Changes

string dataFileName = "/path/to/file/datafile.csv";

const int nRows = 1000; // number of rows to be read

// Create the data source

FileDataSource<CSVFeatureManager> dataSource(dataFileName,

DataSource::doAllocateNumericTable,

DataSource::doDictionaryFromContext);

// Load data from the CSV file

dataSource.loadDataBlock(nRows);