LoadGpuHist Node1 LoadGpuHist + LoadGpuHist() + ~LoadGpuHist() + set_hf1d() + set_d_hf1d() + hf1d() + hf1d_d() + hf1d_h() + LD1D() Node2 struct Node2->Node1 -m_hf1d -m_hf1d_d -m_hf1d_h