@Test
public void visit() {

    DenseVectorSummarizer summarizer = summarizer();
    assertEquals(5, summarizer.count);
    assertArrayEquals(new double[]{15.0, -15.0, 15.0}, summarizer.sum.getData(), 10e-6);
    assertArrayEquals(new double[]{55.0, 55.0, 45.0}, summarizer.squareSum.getData(), 10e-6);
    assertArrayEquals(new double[]{1.0, -5.0, 3.0}, summarizer.min.getData(), 10e-6);
    assertArrayEquals(new double[]{5.0, -1.0, 3.0}, summarizer.max.getData(), 10e-6);
    assertArrayEquals(new double[]{15.0, 15.0, 15.0}, summarizer.normL1.getData(), 10e-6);
}