C++ API Reference for Intel® Data Analytics Acceleration Library 2019 Update 4

dt_cls_traverse_model.cpp

/* file: dt_cls_traverse_model.cpp */
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* Copyright 2014-2019 Intel Corporation.
*
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/*
! Content:
! C++ example of decision tree classification model traversal.
!
! The program trains the decision tree classification model on a training
! datasetFileName and prints the trained model by its depth-first traversing.
!******************************************************************************/
#include "daal.h"
#include "service.h"
#include <cstdio>
using namespace std;
using namespace daal;
using namespace daal::algorithms;
/* Input data set parameters */
string trainDatasetFileName = "../data/batch/decision_tree_train.csv";
string pruneDatasetFileName = "../data/batch/decision_tree_prune.csv";
const size_t nFeatures = 5; /* Number of features in training and testing data sets */
const size_t nClasses = 5; /* Number of classes */
decision_tree::classification::training::ResultPtr trainModel();
void printModel(const daal::algorithms::decision_tree::classification::Model& m);
int main(int argc, char *argv[])
{
checkArguments(argc, argv, 2, &trainDatasetFileName, &pruneDatasetFileName);
decision_tree::classification::training::ResultPtr trainingResult = trainModel();
printModel(*trainingResult->get(classifier::training::model));
return 0;
}
decision_tree::classification::training::ResultPtr trainModel()
{
/* Initialize FileDataSource<CSVFeatureManager> to retrieve the input data from a .csv file */
FileDataSource<CSVFeatureManager> trainDataSource(trainDatasetFileName,
DataSource::notAllocateNumericTable,
DataSource::doDictionaryFromContext);
/* Create Numeric Tables for training data and labels */
NumericTablePtr trainData(new HomogenNumericTable<>(nFeatures, 0, NumericTable::notAllocate));
NumericTablePtr trainGroundTruth(new HomogenNumericTable<>(1, 0, NumericTable::notAllocate));
NumericTablePtr mergedData(new MergedNumericTable(trainData, trainGroundTruth));
/* Retrieve the data from the input file */
trainDataSource.loadDataBlock(mergedData.get());
/* Initialize FileDataSource<CSVFeatureManager> to retrieve the pruning input data from a .csv file */
FileDataSource<CSVFeatureManager> pruneDataSource(pruneDatasetFileName,
DataSource::notAllocateNumericTable,
DataSource::doDictionaryFromContext);
/* Create Numeric Tables for pruning data and labels */
NumericTablePtr pruneData(new HomogenNumericTable<>(nFeatures, 0, NumericTable::notAllocate));
NumericTablePtr pruneGroundTruth(new HomogenNumericTable<>(1, 0, NumericTable::notAllocate));
NumericTablePtr pruneMergedData(new MergedNumericTable(pruneData, pruneGroundTruth));
/* Retrieve the data from the pruning input file */
pruneDataSource.loadDataBlock(pruneMergedData.get());
/* Create an algorithm object to train the Decision tree model */
decision_tree::classification::training::Batch<> algorithm(nClasses);
/* Pass the training data set, labels, and pruning dataset with labels to the algorithm */
algorithm.input.set(classifier::training::data, trainData);
algorithm.input.set(classifier::training::labels, trainGroundTruth);
algorithm.input.set(decision_tree::classification::training::dataForPruning, pruneData);
algorithm.input.set(decision_tree::classification::training::labelsForPruning, pruneGroundTruth);
/* Train the Decision tree model */
algorithm.compute();
/* Retrieve the results of the training algorithm */
return algorithm.getResult();
}
class PrintNodeVisitor : public daal::algorithms::tree_utils::classification::TreeNodeVisitor
{
public:
virtual bool onLeafNode(const tree_utils::classification::LeafNodeDescriptor &desc)
{
for(size_t i = 0; i < desc.level; ++i)
std::cout << " ";
std::cout << "Level " << desc.level << ", leaf node. Response value = " << desc.label << ", Impurity = " << desc.impurity <<
", Number of samples = " << desc.nNodeSampleCount << std::endl;
return true;
}
virtual bool onSplitNode(const tree_utils::classification::SplitNodeDescriptor &desc)
{
for(size_t i = 0; i < desc.level; ++i)
std::cout << " ";
std::cout << "Level " << desc.level << ", split node. Feature index = " << desc.featureIndex <<
", feature value = " << desc.featureValue << ", Impurity = " << desc.impurity <<
", Number of samples = " << desc.nNodeSampleCount << std::endl;
return true;
}
};
void printModel(const daal::algorithms::decision_tree::classification::Model& m)
{
PrintNodeVisitor visitor;
m.traverseDFS(visitor);
}

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