@Test
public void testUpdateLabel(){

    DenseVector label = distance.prepareVectorData(Tuple2.of(denseVector1, null)).getLabel();
    Assert.assertEquals(label.size(), 1);
    Assert.assertEquals(label.get(0), denseVector1.normL2Square(), 0.001);
    FastDistanceMatrixData matrixData = initMatrixData();
    Assert.assertEquals(matrixData.label.numCols(), 2);
    Assert.assertEquals(matrixData.label.numRows(), 1);
    for(int i = 0; i< matrixData.getVectors().numCols(); i++){
        double[] data = matrixData.getVectors().getColumn(i);
        Assert.assertEquals(matrixData.label.getData()[i], BLAS.dot(data, data), 0.01);
    }
}