Added encoder argument to BYOL constructor (#637)

* Added base_encoder argument to BYOL constructor

* Added encoder and MLP dimension args to BYOL

* Update changelog

* Updated docstring

* Update CHANGELOG.md

Co-authored-by: O'Donnell, Garry (DLSLtd,RAL,LSCI) <garry.o'donnell@diamond.ac.uk>
Co-authored-by: Jirka Borovec <Borda@users.noreply.github.com>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

CHANGELOG.md

@@ -15,6 +15,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Replaced `load_boston` with `load_diabetes` in the docs and tests ([#629](https://github.com/PyTorchLightning/lightning-bolts/pull/629))
 
 
+- Added base encoder and MLP dimension arguments to BYOL constructor ([#637](https://github.com/PyTorchLightning/lightning-bolts/pull/637))
+
+
 ### Deprecated
 
 

pl_bolts/models/self_supervised/byol/byol_module.py

@@ -1,6 +1,6 @@
 from argparse import ArgumentParser
 from copy import deepcopy
-from typing import Any
+from typing import Any, Union
 
 import pytorch_lightning as pl
 import torch
@@ -72,6 +72,10 @@ def __init__(
  num_workers: int = 0,
  warmup_epochs: int = 10,
  max_epochs: int = 1000,
+ base_encoder: Union[str, torch.nn.Module] = 'resnet50',
+ encoder_out_dim: int = 2048,
+ projector_hidden_size: int = 4096,
+ projector_out_dim: int = 256,
  **kwargs
  ):
  """
@@ -84,11 +88,15 @@ def __init__(
  num_workers: number of workers
  warmup_epochs: num of epochs for scheduler warm up
  max_epochs: max epochs for scheduler
+ base_encoder: the base encoder module or resnet name
+ encoder_out_dim: output dimension of base_encoder
+ projector_hidden_size: hidden layer size of projector MLP
+ projector_out_dim: output size of projector MLP
  """
  super().__init__()
- self.save_hyperparameters()
+ self.save_hyperparameters(ignore='base_encoder')
 
- self.online_network = SiameseArm()
+ self.online_network = SiameseArm(base_encoder, encoder_out_dim, projector_hidden_size, projector_out_dim)
  self.target_network = deepcopy(self.online_network)
  self.weight_callback = BYOLMAWeightUpdate()
 

pl_bolts/models/self_supervised/byol/models.py

@@ -23,17 +23,17 @@ def forward(self, x):
 
 class SiameseArm(nn.Module):
 
- def __init__(self, encoder=None):
+ def __init__(self, encoder='resnet50', encoder_out_dim=2048, projector_hidden_size=4096, projector_out_dim=256):
  super().__init__()
 
- if encoder is None:
- encoder = torchvision_ssl_encoder('resnet50')
+ if isinstance(encoder, str):
+ encoder = torchvision_ssl_encoder(encoder)
  # Encoder
  self.encoder = encoder
  # Projector
- self.projector = MLP()
+ self.projector = MLP(encoder_out_dim, projector_hidden_size, projector_out_dim)
  # Predictor
- self.predictor = MLP(input_dim=256)
+ self.predictor = MLP(projector_out_dim, projector_hidden_size, projector_out_dim)
 
  def forward(self, x):
  y = self.encoder(x)[0]