AAAI 2023

PC-Conv: Unifying Homophily and Heterophily with Two-fold Filtering

Bingheng Li, Erlin Pan, Zhao Kang

Main figure for PC-Conv: Unifying Homophily and Heterophily with Two-fold Filtering

Abstract

Recently, many carefully crafted graph representation learning methods have achieved impressive performance on either strong heterophilic or homophilic graphs, but not both. Therefore, they are incapable of generalizing well across real-world graphs with different levels of homophily. This is attributed to their neglect of homophily in heterophilic graphs, and vice versa. In this paper, we propose a two-fold filtering mechanism to extract homophily in heterophilic graphs and vice versa. In particular, we extend the graph heat equation to perform heterophilic aggregation of global information from a long distance. The resultant filter can be exactly approximated by the Possion-Charlier (PC) polynomials. To further exploit information at multiple orders, we introduce a powerful graph convolution PC-Conv and its instantiation PCNet for the node classification task. Compared with state-of-the-art GNNs, PCNet shows competitive performance on well-known homophilic and heterophilic graphs. Our implementation is available at https://github.com/uestclbh/PC-Conv.

Proposed method: PCNet

Benchmark Results

Tested on 4 datasets 9 baseline values reported too low

Tables show presented results in global context (best 3 papers + GCN + MLP).

Heterophilic Graphs

#ModelAccuracy ↑Paper
1
P^2GNN
0.9672 ±0.0147
2
DoG
0.9660 ±0.0210
3
GPF-plus
0.9583 ±0.0419
5
ACM-GCN
actual #5 vs paper #91 86 places worse
0.9557 ±0.0360
best reported
actual #5 vs paper #91 86 places worse
paper 0.8784 ±0.0440
34
MLP
0.9230 ±0.0070
39
GGCN
actual #39 vs paper #148 109 places worse
0.9213 ±0.0305
best reported
actual #39 vs paper #148 109 places worse
paper 0.8486 ±0.0455
best today: Graph Wave Networks (WWW 2025)
paper 0.8486 ±0.0455 Δ today 0.0727
40
H2GCN
actual #40 vs paper #148 108 places worse
0.9189 ±0.0393
best reported
actual #40 vs paper #148 108 places worse
paper 0.8486 ±0.0723

Difference within reported uncertainty; not counted as underperformance.

paper 0.8486 ±0.0723 Δ at pub 0.0104 Δ today 0.0703
53
GraphSAGE
0.9000 ±0.0365
104
WRGAT
actual #104 vs paper #173 69 places worse
0.8698
best reported
actual #104 vs paper #173 69 places worse
paper 0.8362 ±0.0550

Difference within reported uncertainty; not counted as underperformance.

paper 0.8362 ±0.0550 Δ today 0.0336
141
GloGNN
actual #141 vs paper #167 26 places worse
0.8524 ±0.0490
best reported
actual #141 vs paper #167 26 places worse
paper 0.8405 ±0.0490

Difference within reported uncertainty; not counted as underperformance.

paper 0.8405 ±0.0490 Δ at pub 0.0027 Δ today 0.0119
211
GAT
actual #211 vs paper #576 365 places worse
0.8162 ±0.0645
best reported
actual #211 vs paper #576 365 places worse
paper 0.5216 ±0.0663
paper 0.5216 ±0.0663 Δ at pub 0.2784 Δ today 0.2946
276
MixHop
0.7784 ±0.0773
This paper
325
LINKX
0.7460 ±0.0837
This paper
#ModelAccuracy ↑Paper
1
P^2GNN
0.9541 ±0.0272
2
ACM-GCN
actual #2 vs paper #87 85 places worse
0.9480 ±0.0380
best reported
actual #2 vs paper #87 85 places worse
paper 0.8514 ±0.0607
3
RF-GCN
0.9429
15
GGCN
actual #15 vs paper #79 64 places worse
0.9230 ±0.0367
best reported
actual #15 vs paper #79 64 places worse
paper 0.8568 ±0.0663

Difference within reported uncertainty; not counted as underperformance.

paper 0.8568 ±0.0663 Δ today 0.0662
24
MLP
0.9136 ±0.0070
68
H2GCN
actual #68 vs paper #136 68 places worse
0.8623 ±0.0471
best reported
actual #68 vs paper #136 68 places worse
paper 0.8270 ±0.0528
best at pub: Graph-Coupled Oscillator Networks (ICML 2022)

Difference within reported uncertainty; not counted as underperformance.

paper 0.8270 ±0.0528 Δ today 0.0353
74
GloGNN
0.8595 ±0.0510
This paper
123
LINKX
actual #123 vs paper #203 80 places worse
0.8346 ±0.0061
best reported
actual #123 vs paper #203 80 places worse
paper 0.7784 ±0.0581

Difference within reported uncertainty; not counted as underperformance.

paper 0.7784 ±0.0581 Δ today 0.0562
138
SAGE
0.8269
158
GAT
actual #158 vs paper #358 200 places worse
0.8190 ±0.0540
best reported
actual #158 vs paper #358 200 places worse
paper 0.6189 ±0.0505
paper 0.6189 ±0.0505 Δ at pub 0.2001
160
WRGAT
0.8162 ±0.0390
This paper
183
MixHop
actual #183 vs paper #249 66 places worse
0.7950 ±0.0630
best reported
actual #183 vs paper #249 66 places worse
paper 0.7351 ±0.0634

Difference within reported uncertainty; not counted as underperformance.

paper 0.7351 ±0.0634 Δ at pub 0.0599
#ModelAccuracy ↑Paper
1
DiGGR
0.4535 ±0.0353
2
TRIGON
0.4402 ±0.0028
3
DoG
0.4320 ±0.0120
16
ACM-GCN
actual #16 vs paper #173 157 places worse
0.4198 ±0.0089
best reported
actual #16 vs paper #173 157 places worse
paper 0.3628 ±0.0109
paper 0.3628 ±0.0109 Δ at pub 0.0032 Δ today 0.0570
38
GCNII
actual #38 vs paper #114 76 places worse
0.4082 ±0.0179
best reported
actual #38 vs paper #114 76 places worse
paper 0.3744 ±0.0130
paper 0.3744 ±0.0130 Δ at pub 0.0117 Δ today 0.0338
42
MLP
0.4026 ±0.0108
58
GloGNN
actual #58 vs paper #106 48 places worse
0.3959 ±0.0029
best reported
actual #58 vs paper #106 48 places worse
paper 0.3770 ±0.0140

Difference within reported uncertainty; not counted as underperformance.

paper 0.3770 ±0.0140 Δ at pub 0.0189
62
GGCN
actual #62 vs paper #113 51 places worse
0.3929 ±0.0048
best reported
actual #62 vs paper #113 51 places worse
paper 0.3754 ±0.0156

Difference within reported uncertainty; not counted as underperformance.

paper 0.3754 ±0.0156 Δ at pub 0.0027 Δ today 0.0175
68
GraphSAGE
0.3899 ±0.0085
71
H2GCN
actual #71 vs paper #198 127 places worse
0.3885 ±0.0117
best reported
actual #71 vs paper #198 127 places worse
paper 0.3570 ±0.0100
paper 0.3570 ±0.0100 Δ at pub 0.0270 Δ today 0.0315
75
WRGAT
actual #75 vs paper #158 83 places worse
0.3860 ±0.0110
best reported
actual #75 vs paper #158 83 places worse
paper 0.3653 ±0.0077
paper 0.3653 ±0.0077 Δ at pub 0.0207
162
MixHop
actual #162 vs paper #297 135 places worse
0.3648 ±0.0120
best reported
actual #162 vs paper #297 135 places worse
paper 0.3222 ±0.0234
paper 0.3222 ±0.0234 Δ at pub 0.0426
180
LINKX
0.3610 ±0.0155
This paper
182
GAT
actual #182 vs paper #406 224 places worse
0.3605 ±0.0035
best reported
actual #182 vs paper #406 224 places worse
paper 0.2744 ±0.0089
paper 0.2744 ±0.0089 Δ at pub 0.0861

LINKX Benchmarks

#ModelAccuracy ↑Paper
1
DC-GNN
0.8669 ±0.0022
2
M2M-GNN
0.8594 ±0.0040
3
GloGNN
actual #3 vs paper #3
0.8574 ±0.0042
actual #3 vs paper #3
paper 0.8574 ±0.0042

Improvement within reported uncertainty; not highlighted.

paper 0.8574 ±0.0042 Δ at pub 0.0014
9
PCNet
0.8475 ±0.0051
This paper
11
LINKX
0.8471 ±0.0052
This paper
13
GPRGNN
actual #13 vs paper #37 24 places worse
0.8455 ±0.0054
best reported
actual #13 vs paper #37 24 places worse
paper 0.8138 ±0.0016
paper 0.8138 ±0.0016 Δ at pub 0.0317
17
MixHop
actual #17 vs paper #20 3 places worse
0.8363 ±0.0054
best reported
actual #17 vs paper #20 3 places worse
paper 0.8347 ±0.0071

Difference within reported uncertainty; not counted as underperformance.

paper 0.8347 ±0.0071 Δ at pub 0.0016
24
H2GCN
actual #24 vs paper #37 13 places worse
0.8320 ±0.0055
best reported
actual #24 vs paper #37 13 places worse
paper 0.8131 ±0.0060
paper 0.8131 ±0.0060 Δ at pub 0.0189
26
ACM-GCN
actual #26 vs paper #30 4 places worse
0.8298 ±0.0063
best reported
actual #26 vs paper #30 4 places worse
paper 0.8252 ±0.0096

Difference within reported uncertainty; not counted as underperformance.

paper 0.8252 ±0.0096 Δ at pub 0.0046
27
GCNII
0.8292 ±0.0059
This paper
29
GIN
0.8268 ±0.0032
31
GCN
0.8247 ±0.0027
This paper
36
GAT
0.8153 ±0.0055
This paper
51
MLP
actual #51 vs paper #57 6 places worse
0.7534 ±0.0064
best reported
actual #51 vs paper #57 6 places worse
paper 0.7361 ±0.0040
paper 0.7361 ±0.0040 Δ at pub 0.0173
54
WRGAT
0.7432 ±0.0053
This paper
SOTA performance (not significantly different from the best) Proposed method (this paper) Baseline / comparison (this paper) Global context (other papers) Best at pub — reported result worse than the best known when published (best reported in green) Best today — OK at publication; today's leaderboard best is elsewhere