Tutorials/MachineLearning101/MachineLearning101.cpp

The GestureRecognitionPipeline is the core module of the Gesture Recognition Toolkit. You can use the GestureRecognitionPipeline to link the various GRT modules together, for instace you can link a PreProcessing module to a FeatureExtraction module to a Classification module and then to a PostProcessing module.

/*
 GRT MIT License
 Copyright (c) <2012> <Nicholas Gillian, Media Lab, MIT>
 
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/*
 MachineLearning101 Example
 
 This example shows you how to:
 - load a dataset from a file
 - partition the dataset into a training dataset and a test dataset
 - setup a gesture recognition pipeline
 - train a KNN classification algorithm using the training dataset
 - test the classification abilities of the KNN algorithm using the test dataset
 - get some test metrics (accuracy, precision, recall, confusion matrix) about how successful the classification was
 */

//You might need to set the specific path of the GRT header relative to your project
#include <GRT/GRT.h>
using namespace GRT;
using namespace std;

int main (int argc, const char * argv[])
{
    //Parse the data filename from the argument list, you should pass in the data path to the iris data set in the GRT data folder
    if( argc != 2 ){
        cout << "Error: failed to parse data filename from command line. You should run this example with one argument pointing to the data filename!\n";
        return EXIT_FAILURE;
    }
    const string filename = argv[1];

    //We are going to use the Iris dataset, you can find more about the orginal dataset at: http://en.wikipedia.org/wiki/Iris_flower_data_set
    
    //Create a new instance of ClassificationData to hold the training data
    ClassificationData trainingData;
    
    //Load the training dataset from a file, the file should be in the same directory as this program
    if( !trainingData.load( filename ) ){
        cout << "Failed to load Iris data from file!\n";
        return EXIT_FAILURE;
    }
    
    //Print some basic stats about the dataset we have loaded
    trainingData.printStats();
    
    //Partition the training dataset into a training dataset and test dataset
    //We will use 60% of the data to train the algorithm and 40% of the data to test it
    //The true parameter flags that we want to use stratified sampling, which means there 
    //should be an equal class distribution between the training and test datasets
    ClassificationData testData = trainingData.split( 60, true );
    
    //Setup the gesture recognition pipeline
    GestureRecognitionPipeline pipeline;
    
    //Add a KNN classification algorithm as the main classifier with a K value of 10
    pipeline << KNN(10);
    
    //Train the KNN algorithm using the training dataset
    if( !pipeline.train( trainingData ) ){
        cout << "Failed to train the pipeline!\n";
        return EXIT_FAILURE;
    }
    
    //Test the KNN model using the test dataset
    if( !pipeline.test( testData ) ){
        cout << "Failed to test the pipeline!\n";
        return EXIT_FAILURE;
    }
    
    //Print some metrics about how successful the classification was
    //Print the accuracy
    cout << "The classification accuracy was: " << pipeline.getTestAccuracy() << "%\n" << endl;
    
    //Print the precision for each class
    for(UINT k=0; k<pipeline.getNumClassesInModel(); k++){
        UINT classLabel = pipeline.getClassLabels()[k];
        double classPrecision = pipeline.getTestPrecision( classLabel );
        cout << "The precision for class " << classLabel << " was " << classPrecision << endl;
    }
    cout << endl;
    
    //Print the recall for each class
    for(UINT k=0; k<pipeline.getNumClassesInModel(); k++){
        UINT classLabel = pipeline.getClassLabels()[k];
        double classRecall = pipeline.getTestRecall( classLabel );
        cout << "The recall for class " << classLabel << " was " << classRecall << endl;
    }
    cout << endl;
    
    //Print the confusion matrix
    MatrixFloat confusionMatrix = pipeline.getTestConfusionMatrix();
    cout << "Confusion Matrix: \n";
    for(UINT i=0; i<confusionMatrix.getNumRows(); i++){
        for(UINT j=0; j<confusionMatrix.getNumCols(); j++){
            cout << confusionMatrix[i][j] << "\t";
        }
        cout << endl;
        
    }
    cout << endl;

    return EXIT_SUCCESS;
}