daisuke.kikuta
first commit
719d0db
import math
import torch
import torch.nn as nn
class MaxReadout(nn.Module):
def __init__(self, state_dim, emb_dim, dropout):
super().__init__()
self.state_dim = state_dim
self.emb_dim = emb_dim
# initial embedding for state
if state_dim > 0:
self.init_linear_state = nn.Linear(state_dim, emb_dim)
# out linear layer
self.out_linear = nn.Linear((1 + int(state_dim > 0))*emb_dim, emb_dim)
# Dropout
self.dropout = nn.Dropout(dropout)
self.reset_parameters()
def reset_parameters(self):
for param in self.parameters():
stdv = 1. / math.sqrt(param.size(-1))
param.data.uniform_(-stdv, stdv)
def forward(self, inputs, node_emb):
"""
Paramters
---------
inputs: dict
mask: torch.LongTensor [batch_size x num_nodes]
state: torch.FloatTensor [batch_size x state_dim]
node_emb: torch.tensor [batch_size x num_nodes x emb_dim]
node embeddings obtained from the node encoder
Returns
-------
h: torch.tensor [batch_size x emb_dim]
graph embeddings
"""
mask = inputs["mask"]
state = inputs["state"]
node_emb = self.dropout(node_emb)
# pooling with a mask
mask = mask.unsqueeze(-1).expand_as(node_emb)
node_emb = node_emb * mask
h, _ = torch.max(node_emb, dim=1) # [batch_size x emb_dim]
# out linear layer
if state is not None and self.state_dim > 0:
state_emb = self.init_linear_state(state) # [batch_size x emb_dim]
h = torch.cat((h, state_emb), -1) # [batch_size x (2*emb_dim)]
return self.out_linear(h)