GBTree Returns Same Value for any sample

edit

Hello,

I am attempting to use the machine learning tool GBTrees in OpenCV. My data wasn't working, so i have generated a simple linear sequence to train the classifier with, this returns the same value on output each time.

    std::string dataFileName = "NZ-SQL-Corpus.csv";
    TrainingData tData;// = ReadDataSource(dataFileName);

    tData.samples = cv::Mat(100,1,CV_32FC1);
    tData.samplesMask = cv::Mat::zeros(100,1,CV_8UC1);
    tData.responses = cv::Mat::zeros(100,1,CV_32FC1);

    for(int i=0;i<tData.samples.rows;i++)
    {
        tData.samples.at<float>(i,0)=i;
        tData.responses.at<float>(i,0)=i;
    }

    cv::Mat train_data = tData.samples.clone();
    cv::Mat mask = tData.samplesMask.clone();
    cv::Mat train_resp = tData.responses.clone();

    cv::GradientBoostingTreeParams params(CvGBTrees::SQUARED_LOSS, 200, 0.8f, 0.01f, 3, true);

    cv::Mat varIdx, sampleIdx, varType;
    varType = cv::Mat( train_data.cols+1, 1, CV_8U );
    varType.setTo(CV_VAR_CATEGORICAL);
    sampleIdx = cv::Mat();

    bool trained = gbTree.train(train_data,CV_ROW_SAMPLE,train_resp,varIdx,sampleIdx,varType,mask,params);
    TestClassifier(tData);

Results....

The red line is the samples, green line is the responses.

The response value is 18.526666641235352 for any value between 1-100 as a sample.

Any tips?