We study the challenging problem for inference tasks on large-scale graph datasets of Graph Neural Networks: huge time and memory consumption, and try to overcome it by reducing reliance on graph structure. Even though distilling graph knowledge to student MLP is an excellent idea, it faces two major problems of positional information loss and low generalization. To solve the problems, we propose a new three-stage multitask distillation framework. In detail, we use Positional Encoding to capture positional information. Also, we introduce Neural Heat Kernels responsible for graph data processing in GNN and utilize hidden layer outputs matching for better performance of student MLP's hidden layers. To the best of our knowledge, it is the first work to include hidden layer distillation for student MLP on graphs and to combine graph Positional Encoding with MLP. We test its performance and robustness with several settings and draw the conclusion that our work can outperform well with good stability. Code implementation is in https://github.com/lijunxian111/KMP.
Figures & tables
Figure 1: Overall structure of our framework. It consists of three stages: GNN pretraining, distillation and inference. We transfer knowledge to student MLP during stage II. Best viewed in color.
Dataset
Models
SAGE
GCN
GAT
MLP
GLNN(SAGE)
KMP(SAGE)
GLNN(GCN)
KMP(GCN)
GLNN(GAT)
KMP(GAT)
Cora
79.70 ± 1.90
79.58 ± 1.01
81.41 ± 1.15
58.66 ± 2.34
78.99 ± 1.90
79.48 ± 1.48
79.43 ± 0.82
80.03 ± 1.19
79.89 ± 1.44
80.44 ± 1.13
Citeseer
70.53 ± 2.16
70.09 ± 2.23
71.76 ± 1.54
58.01 ± 0.96
71.23 ± 2.13
71.96 ± 2.25
71.24 ± 2.98
72.18 ± 2.23
72.44 ± 1.63
72.72 ± 1.18
Pubmed
75.53 ± 2.39
77.96 ± 2.96
78.30 ± 2.44
67.72 ± 3.34
76.32 ± 2.67
76.80 ± 2.01
77.94 ± 2.95
78.48 ± 1.90
76.44 ± 2.28
76.86 ± 2.40
Amazon Photo
90.26 ± 1.14
87.18 ± 4.05
91.61 ± 0.94
78.39 ± 1.71
92.04 ± 0.91
92.23 ± 0.85
89.97 ± 3.08
90.48 ± 2.55
93.01 ± 0.94
93.19 ± 0.78
Amazon Computer
83.23 ± 1.49
80.19 ± 5.18
83.03 ± 2.30
69.01 ± 3.27
84.41 ± 1.51
84.75 ± 1.10
78.42 ± 4.26
78.96 ± 4.27
83.52 ± 2.17
82.94 ± 2.00
Table 1: Results of teachers, baseline models and KMP for trans setting. The best performance of student model is highlighted.
Dataset
Models
SAGE
GCN
GAT
MLP
GLNN(SAGE)
KMP(SAGE)
GLNN(GCN)
KMP(GCN)
GLNN(GAT)
KMP(GAT)
Cora
78.64 ± 2.06
78.90 ± 1.69
81.10 ± 2.46
58.02 ± 2.72
71.94 ± 2.85
71.85 ± 2.40
72.39 ± 2.30
72.86 ± 2.37
72.41 ± 1.48
72.53 ± 1.38
Citeseer
70.83 ± 2.83
68.26 ± 3.65
70.75 ± 3.29
59.46 ± 4.55
70.80 ± 2.63
71.22 ± 2.04
67.15 ± 2.33
68.04 ± 2.52
68.92 ± 2.94
69.17 ± 3.01
Pubmed
74.86 ± 2.97
74.40 ± 2.94
76.64 ± 2.97
66.14 ± 5.03
74.76 ± 2.69
74.92 ± 3.03
74.89 ± 2.81
75.44 ± 2.75
74.63 ± 2.81
74.53 ± 3.06
Amazon Photo
91.33 ± 1.56
89.28 ± 2.12
92.27 ± 1.50
79.01 ± 1.80
89.75 ± 1.58
90.26 ± 2.43
88.54 ± 1.94
89.10 ± 1.69
90.02 ± 2.48
90.54 ± 1.37
Amazon Computer
82.73 ± 1.54
75.21 ± 3.56
83.38 ± 2.50
67.95 ± 3.88
81.18 ± 2.53
80.94 ± 2.33
74.01 ± 3.26
74.05 ± 4.01
81.08 ± 2.54
81.56 ± 2.57
Table 2: Results of teachers, baseline models and KMP for induc setting. The best performance of student model is highlighted.
Dataset
Models
SAGE
GCN
GAT
MLP
GLNN(SAGE)
KMP(SAGE)
GLNN(GCN)
KMP(GCN)
GLNN(GAT)
KMP(GAT)
OGBN-Arxiv
71.54 ± 0.47
69.84 ± 0.41
73.45 ± 0.29
54.12 ± 2.97
64.48 ± 1.29
64.31 ± 0.50
60.07 ± 0.18
60.96 ± 1.11
63.45 ± 4.06
65.02 ± 2.23
OGBN-Products
78.07 ± 0.06
75.02 ± 0.23
78.35 ± 0.14
60.88 ± 0.17
67.44 ± 0.60
68.01 ± 0.52
66.92 ± 0.41
66.07 ± 0.64
67.53 ± 0.33
68.20 ± 0.69
Table 3: Results of teachers, baseline models and KMP for trans setting on large-scale graph datasets. The best performance of student model is highlighted.
Dataset
Models
SAGE
GCN
GAT
MLP
GLNN(SAGE)
KMP(SAGE)
GLNN(GCN)
KMP(GCN)
GLNN(GAT)
KMP(GAT)
OGBN-Arxiv
70.53 ± 0.58
69.79 ± 0.41
—
54.46 ± 2.75
58.83 ± 0.33
59.31 ± 0.22
58.94 ± 0.71
60.01 ± 1.02
—
—
OGBN-Products
77.25 ± 0.22
74.93 ± 0.15
—
61.05 ± 0.36
65.24 ± 0.39
65.93 ± 0.53
64.37 ± 0.13
63.95 ± 0.17
—
—
Table 4: Results of teachers, baseline models and KMP for induc setting on large-scale graph datasets. The best performance of student model is highlighted. (’—’ means that the GNN shows poor performance and we do not use it as teacher.)
Dataset
Models(SAGE teacher, trans)
Models(SAGE teacher, induc)
KMP(ours)
KMP+PE(ours)
SA−MLP
KMP(ours)
KMP+PE(ours)
SA−MLP
Cora
79.48 ± 1.48
80.97 ± 1.03
79.33 ± 1.55
71.85 ± 2.40
71.90 ± 1.81
71.54 ± 2.26
Citeseer
71.96 ± 2.25
72.07 ± 2.51
71.25 ± 1.57
71.22 ± 2.04
71.46 ± 2.65
70.95 ± 2.49
Pubmed
76.80 ± 2.01
76.58 ± 2.84
76.45 ± 2.50
74.92 ± 3.03
74.71 ± 2.09
74.99 ± 3.74
Amazon Photo
92.27 ± 1.50
92.38 ± 0.82
90.67 ± 0.93
90.26 ± 2.43
90.77 ± 0.84
90.27 ± 1.44
Amazon Computer
84.75 ± 1.10
85.10 ± 1.66
83.38 ± 2.50
80.94 ± 2.33
81.50 ± 2.58
81.01 ± 2.89
Table 5: Results of KMP+PE, KMP and SA-MLP for both trans and inductive setting. The best performance of the student model is highlighted.
Figure 2: Results of Robustness study with different teachers on three datasets. The x-axis shows percentage of feature noise and y-axis means test accuracy(%).
Figure 3: Results of sensitiveness study with different teachers on three datasets. Mean and variance of test accuracy reported. We study if changes of γ can influence student MLP’s performance greatly. The x-axis shows different γ s and y-axis means test accuracy(%) with them.
Dataset
Models
Teacher
MLP
GLNN
KMP
MiniGC
91.90 ± 3.47
66.35 ± 5.36
75.44 ± 4.69
78.95 ± 5.01
Table 6: Results for graph classification on MiniGC dataset. The best performance of student model is highlighted.
Appendix figures & tables5 assets
Supplementary material from the paper’s appendix.
Appendix
Dataset
Nodes
Edges
Feature dim
Classes
Cora
2708
5429
1433
7
Citeseer
3327
4732
3703
6
Pubmed
19717
44324
500
3
Amazon Photo
7487
119043
745
8
Amazon Computer
13381
245778
767
10
OGBN-Arxiv
169343
1166243
128
40
Appendix
Table 7: Details of the seven used datasets
GCN
SAGE
GAT
number of layers
2
2
2
hidden layer dim
64
128
128
weight decay
0.001
5e-4
0.01
dropout ratio
0.8
0
0.6
attention dropout ratio
—
—
0.6
fan_out
—
5,5
—
Appendix
Table 8: Experiment settings for the 5 datasets.
γ
0.1,0.3,0.5,0.7,0.9,1,3,10,30
temperature( t )
0.25,0.5,1,2,4,10
θ (percentage of hard labels)
0,0.2,0.4,0.6,0.8,1
learning rate
0.01,5e-3,1e-3,5e-4,1e-4
Appendix
Table 9: Grid Search of hyperparameters.
Figure 4: Results of trainable kernel on three benchmark datasets, compared to kernels without self training
School of Computer Science and Technology, Xidian University · School of Computing and Artificial Intelligence, Southwest Jiaotong University · School of Information Science and Engineering, Chongqing Jiaotong University