pytorch / 2 / generated / torch.nn.transformerencoder.html

TransformerEncoder

class torch.nn.TransformerEncoder(encoder_layer, num_layers, norm=None, enable_nested_tensor=True, mask_check=True) [source]

TransformerEncoder is a stack of N encoder layers. Users can build the BERT(https://arxiv.org/abs/1810.04805) model with corresponding parameters.

Parameters
  • encoder_layer – an instance of the TransformerEncoderLayer() class (required).
  • num_layers – the number of sub-encoder-layers in the encoder (required).
  • norm – the layer normalization component (optional).
  • enable_nested_tensor – if True, input will automatically convert to nested tensor (and convert back on output). This will improve the overall performance of TransformerEncoder when padding rate is high. Default: True (enabled).
Examples::
>>> encoder_layer = nn.TransformerEncoderLayer(d_model=512, nhead=8)
>>> transformer_encoder = nn.TransformerEncoder(encoder_layer, num_layers=6)
>>> src = torch.rand(10, 32, 512)
>>> out = transformer_encoder(src)
forward(src, mask=None, src_key_padding_mask=None, is_causal=None) [source]

Pass the input through the encoder layers in turn.

Parameters
  • src (Tensor) – the sequence to the encoder (required).
  • mask (Optional[Tensor]) – the mask for the src sequence (optional).
  • src_key_padding_mask (Optional[Tensor]) – the mask for the src keys per batch (optional).
  • is_causal (Optional[bool]) – If specified, applies a causal mask as mask. Default: None; try to detect a causal mask. Warning: is_causal provides a hint that mask is the causal mask. Providing incorrect hints can result in incorrect execution, including forward and backward compatibility.
Return type

Tensor

Shape:

see the docs in Transformer class.

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https://pytorch.org/docs/2.1/generated/torch.nn.TransformerEncoder.html