File size: 7,455 Bytes
2f54ec8
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
import torch
import torch.nn as nn
from torch_geometric.nn.aggr import (
    AttentionalAggregation,
    GraphMultisetTransformer,
    MaxAggregation,
    MeanAggregation,
    SetTransformerAggregation,
)

class CatAggregation(nn.Module):
    def __init__(self):
        super().__init__()
        self.flatten = nn.Flatten(1, 2)

    def forward(self, x, index=None):
        return self.flatten(x)


class HeterogeneousAggregator(nn.Module):
    def __init__(
        self,
        input_dim,
        hidden_dim,
        output_dim,
        pooling_method,
        pooling_layer_idx,
        input_channels,
        num_classes,
    ):
        super().__init__()
        self.pooling_method = pooling_method
        self.pooling_layer_idx = pooling_layer_idx
        self.input_channels = input_channels
        self.num_classes = num_classes

        if pooling_layer_idx == "all":
            self._pool_layer_idx_fn = self.get_all_layer_indices
        elif pooling_layer_idx == "last":
            self._pool_layer_idx_fn = self.get_last_layer_indices
        elif isinstance(pooling_layer_idx, int):
            self._pool_layer_idx_fn = self.get_nth_layer_indices
        else:
            raise ValueError(f"Unknown pooling layer index {pooling_layer_idx}")

        if pooling_method == "mean":
            self.pool = MeanAggregation()
        elif pooling_method == "max":
            self.pool = MaxAggregation()
        elif pooling_method == "cat":
            self.pool = CatAggregation()
        elif pooling_method == "attentional_aggregation":
            self.pool = AttentionalAggregation(
                gate_nn=nn.Sequential(
                    nn.Linear(input_dim, hidden_dim),
                    nn.SiLU(),
                    nn.Linear(hidden_dim, 1),
                ),
                nn=nn.Sequential(
                    nn.Linear(input_dim, hidden_dim),
                    nn.SiLU(),
                    nn.Linear(hidden_dim, output_dim),
                ),
            )
        elif pooling_method == "set_transformer":
            self.pool = SetTransformerAggregation(
                input_dim, heads=8, num_encoder_blocks=4, num_decoder_blocks=4
            )
        elif pooling_method == "graph_multiset_transformer":
            self.pool = GraphMultisetTransformer(input_dim, k=8, heads=8)
        else:
            raise ValueError(f"Unknown pooling method {pooling_method}")

    def get_last_layer_indices(
        self, x, layer_layouts, node_mask=None, return_dense=False
    ):
        batch_size = x.shape[0]
        device = x.device

        # NOTE: node_mask needs to exist in the heterogeneous case only
        if node_mask is None:
            node_mask = torch.ones_like(x[..., 0], dtype=torch.bool, device=device)

        valid_layer_indices = (
            torch.arange(node_mask.shape[1], device=device)[None, :] * node_mask
        )
        last_layer_indices = valid_layer_indices.topk(
            k=self.num_classes, dim=1
        ).values.fliplr()

        if return_dense:
            return torch.arange(batch_size, device=device)[:, None], last_layer_indices

        batch_indices = torch.arange(batch_size, device=device).repeat_interleave(
            self.num_classes
        )
        return batch_indices, last_layer_indices.flatten()

    def get_nth_layer_indices(
        self, x, layer_layouts, node_mask=None, return_dense=False
    ):
        batch_size = x.shape[0]
        device = x.device

        cum_layer_layout = [
            torch.cumsum(torch.tensor([0] + layer_layout), dim=0)
            for layer_layout in layer_layouts
        ]

        layer_sizes = torch.tensor(
            [layer_layout[self.pooling_layer_idx] for layer_layout in layer_layouts],
            dtype=torch.long,
            device=device,
        )
        batch_indices = torch.arange(batch_size, device=device).repeat_interleave(
            layer_sizes
        )
        layer_indices = torch.cat(
            [
                torch.arange(
                    layout[self.pooling_layer_idx],
                    layout[self.pooling_layer_idx + 1],
                    device=device,
                )
                for layout in cum_layer_layout
            ]
        )
        return batch_indices, layer_indices

    def get_all_layer_indices(
        self, x, layer_layouts, node_mask=None, return_dense=False
    ):
        """Imitate flattening with indexing"""
        batch_size, num_nodes = x.shape[:2]
        device = x.device
        batch_indices = torch.arange(batch_size, device=device).repeat_interleave(
            num_nodes
        )
        layer_indices = torch.arange(num_nodes, device=device).repeat(batch_size)
        return batch_indices, layer_indices

    def forward(self, x, layer_layouts, node_mask=None):
        # NOTE: `cat` only works with `pooling_layer_idx == "last"`
        return_dense = self.pooling_method == "cat" and self.pooling_layer_idx == "last"
        batch_indices, layer_indices = self._pool_layer_idx_fn(
            x, layer_layouts, node_mask=node_mask, return_dense=return_dense
        )

        flat_x = x[batch_indices, layer_indices]
        return self.pool(flat_x, index=batch_indices)


class HomogeneousAggregator(nn.Module):
    def __init__(
        self,
        pooling_method,
        pooling_layer_idx,
        layer_layout,
    ):
        super().__init__()
        self.pooling_method = pooling_method
        self.pooling_layer_idx = pooling_layer_idx
        self.layer_layout = layer_layout

    def forward(self, node_features, edge_features):
        if self.pooling_method == "mean" and self.pooling_layer_idx == "all":
            graph_features = node_features.mean(dim=1)
        elif self.pooling_method == "max" and self.pooling_layer_idx == "all":
            graph_features = node_features.max(dim=1).values
        elif self.pooling_method == "mean" and self.pooling_layer_idx == "last":
            graph_features = node_features[:, -self.layer_layout[-1] :].mean(dim=1)
        elif self.pooling_method == "cat" and self.pooling_layer_idx == "last":
            graph_features = node_features[:, -self.layer_layout[-1] :].flatten(1, 2)
        elif self.pooling_method == "mean" and isinstance(self.pooling_layer_idx, int):
            graph_features = node_features[
                :,
                self.layer_idx[self.pooling_layer_idx] : self.layer_idx[
                    self.pooling_layer_idx + 1
                ],
            ].mean(dim=1)
        elif self.pooling_method == "cat_mean" and self.pooling_layer_idx == "all":
            graph_features = torch.cat(
                [
                    node_features[:, self.layer_idx[i] : self.layer_idx[i + 1]].mean(
                        dim=1
                    )
                    for i in range(len(self.layer_layout))
                ],
                dim=1,
            )
        elif self.pooling_method == "mean_edge" and self.pooling_layer_idx == "all":
            graph_features = edge_features.mean(dim=(1, 2))
        elif self.pooling_method == "max_edge" and self.pooling_layer_idx == "all":
            graph_features = edge_features.flatten(1, 2).max(dim=1).values
        elif self.pooling_method == "mean_edge" and self.pooling_layer_idx == "last":
            graph_features = edge_features[:, :, -self.layer_layout[-1] :].mean(
                dim=(1, 2)
            )
        return graph_features