gill / gill /layers.py
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Initial commit.
b6f5818
import torch
from torch import nn
class TextFcLayer(nn.Module):
"""Layers used in mapping text embeddings to visual outputs."""
def __init__(self, in_dim: int, out_dim: int, num_input_tokens: int = 1, num_output_tokens: int = 1, mode: str = 'linear'):
super().__init__()
self.num_input_tokens = num_input_tokens
self.num_output_tokens = num_output_tokens
self.mode = mode
if mode == 'linear':
self.model = nn.Linear(in_dim, out_dim)
elif mode == 'gill_mapper': # TODO(jykoh): Rename to GILLMapper
hidden_dim = 512
self.fc = nn.Linear(in_dim, hidden_dim)
self.tfm = nn.Transformer(batch_first=True, norm_first=True,
d_model=hidden_dim, num_encoder_layers=4, num_decoder_layers=4,
dim_feedforward=hidden_dim * 4, dropout=0.0, nhead=4)
self.model = nn.Linear(hidden_dim, out_dim)
self.query_embs = nn.Parameter(torch.randn(1, num_output_tokens, hidden_dim))
else:
raise NotImplementedError(mode)
def forward(self, x: torch.Tensor, input_embs: torch.Tensor) -> torch.Tensor:
outputs = None
if self.mode == 'gill_mapper':
x = x + input_embs
if isinstance(self.model, nn.ModuleList):
assert len(self.model) == x.shape[1] == self.num_input_tokens, (len(self.model), x.shape, self.num_input_tokens)
outputs = []
for i in range(self.num_input_tokens):
outputs.append(self.model[i](x[:, i, :])) # (N, D)
outputs = torch.stack(outputs, dim=1) # (N, T, D)
else:
if self.mode == 'gill_mapper':
x = self.fc(x)
x = self.tfm(x, self.query_embs.repeat(x.shape[0], 1, 1))
outputs = self.model(x)
if outputs.shape[1] != self.num_output_tokens and self.mode == 'linear':
if self.mode == 'linear':
outputs = outputs[:, :self.num_output_tokens, :]
else:
raise NotImplementedError
assert outputs.shape[1] == 1 or (outputs.shape[1] * outputs.shape[2] == self.num_output_tokens * 768), (outputs.shape, self.num_output_tokens)
return outputs # (N, T, D)