m_Splitter.setNodeWidthNormalization(m_NormalizeNodeWidth);
// building tree
m_NumNodes = m_NumLeaves = 1;
m_MaxDepth = 0;
m_Root = new KDTreeNode(m_NumNodes, 0, m_Instances.numInstances() - 1,
universe);
splitNodes(m_Root, universe, m_MaxDepth + 1);
}