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2026-07-13 13:35:51 +08:00

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2.3 KiB
Python

"""
Graph Attention Networks in DGL using SPMV optimization.
References
----------
Paper: https://arxiv.org/pdf/2105.14491.pdf
Author's code: https://github.com/tech-srl/how_attentive_are_gats
"""
import torch
import torch.nn as nn
from dgl.nn import GATv2Conv
class GATv2(nn.Module):
def __init__(
self,
num_layers,
in_dim,
num_hidden,
num_classes,
heads,
activation,
feat_drop,
attn_drop,
negative_slope,
residual,
):
super(GATv2, self).__init__()
self.num_layers = num_layers
self.gatv2_layers = nn.ModuleList()
self.activation = activation
# input projection (no residual)
self.gatv2_layers.append(
GATv2Conv(
in_dim,
num_hidden,
heads[0],
feat_drop,
attn_drop,
negative_slope,
False,
self.activation,
bias=False,
share_weights=True,
)
)
# hidden layers
for l in range(1, num_layers):
# due to multi-head, the in_dim = num_hidden * num_heads
self.gatv2_layers.append(
GATv2Conv(
num_hidden * heads[l - 1],
num_hidden,
heads[l],
feat_drop,
attn_drop,
negative_slope,
residual,
self.activation,
bias=False,
share_weights=True,
)
)
# output projection
self.gatv2_layers.append(
GATv2Conv(
num_hidden * heads[-2],
num_classes,
heads[-1],
feat_drop,
attn_drop,
negative_slope,
residual,
None,
bias=False,
share_weights=True,
)
)
def forward(self, g, inputs):
h = inputs
for l in range(self.num_layers):
h = self.gatv2_layers[l](g, h).flatten(1)
# output projection
logits = self.gatv2_layers[-1](g, h).mean(1)
return logits